Leaf Me Alone Labbook[1]

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Holt Science and Technology 72 The World of Life Science

When performing an experiment, you usually need to collect data. To understandthe data, you can often organize them into a graph. Graphs can show trends andpatterns that you might not notice in a table or list. In this exercise, you will prac-tice collecting data and organizing the data into a graph.

MATERIALS

SAFETY INFORMATION

PROCEDURE

1. Pour 200 mL of water into a 400 mL beaker. Add ice to the beaker until thewaterline is at the 400 mL mark.

2. Place a Celsius thermometer into the beaker. Use a thermometer clip toprevent the thermometer from touching the bottom of the beaker. Record thetemperature of the ice water.

3. Place the beaker and thermometer on a hot plate. Turn the hot plate onmedium heat, and record the temperature every minute until the water tem-perature reaches 100°C.

4. Using heat-resistant gloves, remove the beaker from the hot plate. Continue torecord the temperature of the water each minute for 10 more minutes.Caution: Don’t forget to turn off the hot plate.

5. On a piece of graph paper, create a graph similar to the one on the next page.Label the horizontal axis (the x-axis) “Time (min),” and mark the axis inincrements of 1 min as shown. Label the vertical axis (the y-axis)“Temperature (°C),” and mark the axis in increments of 10° as shown.

Name Class Date

Graphing DataSkills Practice Lab DATASHEET FOR LABBOOK

• beaker, 400 mL

• clock (or watch) with a second hand

• gloves, heat-resistant

• hot plate

• ice

• paper, graph

• thermometer, Celsius, with a clip

• water, 200 mL



6. Find the 1 min mark on the x-axis, and move up the graph to the temperatureyou recorded at 1 min. Place a dot on the graph at that point. Plot each tem-perature in the same way. When you have plotted all of your data, connect thedots with a smooth line.

ANALYZE THE RESULTS

1. Examine your graph. Do you think the water heated faster than it cooled?Explain.

2. Estimate what the temperature of the water was 2.5 min after you placed thebeaker on the hot plate. Explain how you can make a good estimate of tem-perature between those you recorded.

DRAW CONCLUSIONS

3. Explain how a graph may give more information than the same data in a table.

Name Class Date

Graphing Data continued

0

1 2 3 4 5 6 7 8 9 10

10

20

30

40

50

60

70

80

90

100

11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

Time (min)

Tem

pera

ture

(°C

)


Holt Science and Technology 62 It’s Alive!! Or Is It?

The chief baker at the Best-Bread Bakery thinks that the yeast the bakeryreceived may be dead. Yeast is a central ingredient in bread. Yeast is a livingorganism, a member of the kingdom Fungi, and it undergoes the same lifeprocesses as other living organisms. When yeast grows in the presence of oxygenand other nutrients, yeast produces carbon dioxide. The gas forms bubbles thatcause bread dough to rise. Thousands of dollars may be lost if the yeast is dead.

The Best-Bread Bakery has requested that you test the yeast. The bakery hasfurnished samples of live yeast and some samples of the yeast in question.

MATERIALS

SAFETY INFORMATION

PROCEDURE

1. Use the table below to record your data.

Name Class Date

The Best-Bread Bakery DilemmaSkills Practice Lab DATASHEET FOR LABBOOK

• beaker, 250 mL

• flour


• graduated cylinder

• hot plate

• magnifying lens

• scoopula (or small spoon)

• stirring sticks, wooden (3)

• sugar

• test-tube rack

• test tubes (3) (or clear plastic cups)

• thermometer, Celsius, with clip

• water, 125 mL

• yeast samples (live, A, and B)

DeadYeast 0 5 10 15 20 25 orSample Observations min min min min min min alive?

Live

Sample A

Sample B



2. Examine each yeast sample with a magnifying lens. You may want to sniff thesamples to determine the presence of an odor. (Your teacher will demonstratethe appropriate way to detect odors in this lab.) Record your observations inthe data table.

3. Label three test tubes or plastic cups “Live Yeast,” “Sample A Yeast,” and“Sample B Yeast.”

4. Fill a beaker with 125 mL of water, and place the beaker on a hot plate. Use athermometer to be sure the water does not get warmer than 32°C. Attach thethermometer to the side of the beaker with a clip so the thermometer doesn’ttouch the bottom of the beaker. Turn off the hot plate when the water temperature reaches 32°C.

5. Add a small scoop (about 1/2 tsp) of each yeast sample to the correctlylabeled container. Add a small scoop of sugar to each container.

6. Add 10 mL of the warm water to each container, and stir.

7. Add a small scoop of flour to each container, and stir again. The flour willhelp make the process more visible but is not necessary as food for the yeast.

8. Observe the samples carefully. Look for bubbles. Make observations at 5 min intervals. Write your observations in the data table.

9. In the last column of the data table, write “alive” or “dead” based on yourobservations during the experiment.

ANALYZE THE RESULTS

1. Describe any differences in the yeast samples before the experiment.

2. Describe the appearance of the yeast samples at the conclusion of the experiment.

3. Why was a sample of live yeast included in the experiment?

Name Class Date

The Best-Bread Bakery Dilemma continued



4. Why was sugar added to the samples?

5. Based on your observations, is either Sample A or Sample B alive?

DRAW CONCLUSIONS

6. Write a letter to the Best-Bread Bakery stating your recommendation to use ornot use the yeast samples. Give reasons for your recommendation.

APPLYING YOUR DATA

Based on your observations of the nutrient requirements of yeast, design anexperiment to determine the ideal combination of nutrients. Vary the amount ofnutrients, or examine different energy sources.

Name Class Date



Holt Science and Technology 67 Cells: The Basic Units of Life

You have probably used a microscope to look at single-celled organisms. Theycan be found in pond water. In the following exercise, you will look atProtococcus—algae that form a greenish stain on tree trunks, wooden fences,flowerpots, and buildings.

MATERIALS

• eyedropper

• microscope

• microscope slide and coverslip

• Protococcus (or other algae)

• water

SAFETY INFORMATION

PROCEDURE

1. Locate some Protococcus. Scrape a small sample into a container. Bring thesample to the classroom, and make a wet mount of it as directed by yourteacher. If you can’t find Protococcus outdoors, look for algae on the glass inan aquarium. Such algae may not be Protococcus, but it will be a very goodsubstitute.

2. Set the microscope on low power to examine the algae. On a separate sheetof paper, draw the cells that you see.

3. Switch to high power to examine a single cell. Draw the cell.

4. You will probably notice that each cell contains several chloroplasts. Label achloroplast on your drawing. What is the function of the chloroplast?

5. Another structure that should be clearly visible in all the algae cells is thenucleus. Find the nucleus in one of your cells, and label it on your drawing.What is the function of the nucleus?

6. What does the cytoplasm look like? Describe any movement you see insidethe cells.

Name Class Date

Cells Alive!Skills Practice Lab DATASHEET FOR LABBOOK



ANALYZE THE RESULTS

1. Are Protococcus single-celled organisms or multicellular organisms?

2. How are Protococcus different from amoebas?

Name Class Date

Cells Alive! continued


Holt Science and Technology 71 The Cell in Action

Every second of your life, your body’s trillions of cells take in, use, and storeenergy. They repair themselves, reproduce, and get rid of waste. Together, theseprocesses are called metabolism. Your cells use the food that you eat to providethe energy you need to stay alive.

Your Basal Metabolic Rate (BMR) is a measurement of the energy that yourbody needs to carry out all the basic life processes while you are at rest. Theseprocesses include breathing, keeping your heart beating, and keeping your body’stemperature stable. Your BMR is influenced by your gender, your age, and manyother things. Your BMR may be different from everyone else’s, but it is normal foryou. In this activity, you will find the amount of energy, measured in Calories, youneed every day in order to stay alive

MATERIALS

• bathroom scale

• tape measure

PROCEDURE

1. Find your weight on a bathroom scale. If the scale measures in pounds, youmust convert your weight in pounds to your mass in kilograms. To convertyour weight in pounds (lb) to mass in kilograms (kg), multiply the number ofpounds by 0.454.

Example: If Carlos 125 lbweighs 125 lb, his � 0.454mass in kilograms is: 56.75 kg

2. Use a tape measure to find your height. If the tape measures in inches, con-vert your height in inches to height in centimeters. To convert your height ininches (in.) to your height in centimeters (cm), multiply the number of inchesby 2.54

If Carlos is 62 in. 62 in. tall, his height in � 2.54centimeters is: 157.48 cm

3. Now that you know your height and mass, use the appropriate formula belowto get a close estimate of your BMR. Your answer will give you an estimate ofthe number of Calories your body needs each day just to stay alive.

Name Class Date

Stayin’ Alive!Skills Practice Lab DATASHEET FOR LABBOOK



4. Your metabolism is also influenced by how active you are. Talking, walking,and playing games all take more energy than being at rest. To get an idea ofhow many Calories your body needs each day to stay healthy, select thelifestyle that best describes yours from the table below. Then multiply yourBMR by the activity factor.

ANALYZE THE RESULTS

1. In what way could you compare your whole body to a single cell? Explain.

2. Does an increase in activity increase your BMR? Does an increase in activityincrease your need for Calories? Explain your answers.

Name Class Date

Stayin’ Alive! continued

Females

65�(10 � your mass in kilograms)

�(1.8 � your height in centimeters)

� (4.7 � your age in years)

Males

66� (13.5 � your mass in kilograms)

� (5 � your height in centimeters)


ACTIVITY FACTORS

ActivityActivity lifestyle factor

Moderately inactive(normal, everyday activities) 1.3

Moderately active(exercise 3 to 4 times a week) 1.4

Very active (exercise 4 to 6 times a week) 1.6

Extremely active(exercise 6 to 7 times a week) 1.8

CALCULATING YOUR BMR



DRAW CONCLUSIONS

3. If you are moderately inactive, how many more Calories would you need ifyou began to exercise every day?

APPLYING YOUR DATA

The best energy sources are those that supply the correct amount of Calories foryour lifestyle and also provide the nutrients you need. Research in the library oron the Internet to find out which kinds of foods are the best energy sources foryou. How does your list of best energy sources compare with your diet?

List everything you eat and drink in 1 day. Find out how many Calories are ineach item, and find the total number of Calories you have consumed. How doesthis number of Calories compare with the number of Calories you need each dayfor all your activities?

Name Class Date



Holt Science and Technology 70 Heredity

Have you ever wondered about the traits you inherited from your parents? Doyou have a trait that neither of your parents has? In this project, you will developa family tree, or pedigree, similar to the one shown in the diagram below. You willtrace an inherited trait through a family to determine how it has passed from generation to generation.

PROCEDURE

1. The diagram at rightshows a family history.On a separate piece ofpaper, draw a similardiagram of the familyyou have chosen.Include as many familymembers as possible,such as grandparents,parents, children, andgrandchildren. Usecircles to representfemales and squares torepresent males. Youmay include otherinformation, such as thefamily member’s name,birth date, or picture.

2. Use table below to record data about your family. Survey each of the familymembers shown in your family tree. Ask them if they have hair on the middlesegment of their fingers. Write each person’s name in the appropriate square.Explain to each person that it is normal to have either trait. The presence ofhair on the middle segment is the dominant form of this trait.

Name Class Date

Tracing TraitsInquiry Lab DATASHEET FOR LABBOOK

Pedigree

Tom1

Jane2

Fran1

Harry2

Mary3

Bob4

Luke1

Mary2

Dylan3

Rosa4

Nathan1

Alicia2

Tara3

IGrandparents

IIParents

IIIChildren

IVGrandchildren

Family members with Family members withDominant trait Recessive trait the dominant trait the recessive trait

Hair present on the Hair absent on themiddle segment of middle segment offingers (H) fingers (h)



3. Trace this trait throughout the family tree you diagrammed in step 1. Shade orcolor the symbols of the family members who demonstrate the dominant formof this trait.

ANALYZE THE RESULTS

1. What percentage of the family members demonstrate the dominant form ofthe trait? Calculate this by counting the number of people who have thedominant trait and dividing this number by the total number of people yousurveyed. Multiply your answer by 100. An example has been done below.

Example: Calculating percentage

10 people with trait � 120 people surveyed 2

1 � 0.50 � 100 � 50% 2

2. What percentage of the family members demonstrate the recessive form ofthe trait? Why doesn’t every family member have the dominant form of thetrait?

3. Choose one of the family members who demonstrates the recessive form ofthe chosen trait. What is this person’s genotype? What are the possible genotypes for the parents of this individual? Does this person have any brothers or sisters? Do they show the dominant or recessive trait?

Name Class Date

Tracing Traits continued



DRAW CONCLUSIONS

4. In the space below, draw a Punnett squarelike the one at right. Use this to determinethe genotypes of the parents of the personyou chose in step 3. Write this person’sgenotype in the bottom right-hand corner of your Punnett square. Hint: There may be more than one possible genotype for the parents. Don’t forget to consider the genotypes of the person’s brothers and sisters.

Name Class Date


? ?

?

?

Father

Mother


Holt Science and Technology 66 The History of Life on Earth

Carbon-14 is a special unstable element used in the absolute dating of materialthat was once alive, such as fossil bones. Every 5,730 years, half of the carbon-14in a fossil specimen decays or breaks down into a more stable element. In the fol-lowing experiment you will see how pennies can show the same kind of “decay.”

MATERIALS

• container with a cover, large

• pennies (100)

PROCEDURE

1. Place 100 pennies in a large, covered container. Shake the container severaltimes, and remove the cover. Carefully empty the container on a flat surfacemaking sure the pennies don’t roll away.

2. Remove all the coins that have the “head” side of the coin turned upward.Record the number of pennies removed and the number of pennies remainingin the data table below.

3. Repeat the process until no pennies are left in the container. Remember toremove only the coins showing “heads.”

Name Class Date

The Half-life of PenniesSkills Practice Lab DATASHEET FOR LABBOOK

Number NumberShake of coins of coins

number remaining removed

1

2

3

4

5

6

7

8

9



4. On the graph below, label the x-axis “Number of shakes,” and label the y-axis“Pennies remaining.” Using data from your data table, plot the number ofcoins remaining at each shake on your graph. Add squares for number ofshakes, if necessary.

ANALYZE THE RESULTS

1. Examine the Half-life of Carbon-14 graph above. Compare the graph you havemade for pennies with the one for carbon-14. Explain any similarities that you see.

Name Class Date

The Half-life of Pennies continued

0 1 2 3 4 5

6.2512.5

25

50

100

Half-life of Pennies100

75

50

25

0 1 2 3 4 5

Half-life of Carbon = 14

Grams ofcarbon=14

Number of half-lives (5,730)



2. Recall that the probability of landing “heads” in a coin toss is 1/2. Use thisinformation to explain why the remaining number of pennies is reduced byabout half each time they are shaken and tossed.

Name Class Date



Holt Science and Technology 61 Classification

You are a crew member on the USS Adventure. TheAdventure has been on a 5-year mission to collectlife-forms from outside the solar system. On the voyage back to Earth, your ship went through ameteor shower, which ruined several of thecompartments containing the extraterrestrial life-forms. Now it is necessary to put more than onelife-form in the same compartment.

You have only three undamagedcompartments in your starship. You and your crewmates must stay in one compartment, and thatcompartment should be used for extraterrestrial life-forms only if absolutely necessary. You and yourcrewmates must decide which of the life-forms couldbe placed together. It is thought that similar life-formswill have similar needs. You can use only observablecharacteristics to group the life-forms.

PROCEDURE

1. Use the data table below to make observations about the charac-teristics of the various life-forms pictured on this page.Look at the images in yourtextbook to observe color.

LIFE-FORM CHARACTERISTICS

Name Class Date

Voyage of the USS AdventureSkills Practice Lab DATASHEET FOR LABBOOK

Color Shape Legs Eyes

Life-form 1

Life-form 2

Life-form 3

Life-form 4

Life-form 5

Life-form 6

Life-form 7

Life-form 1

Life-form 2

Life-form 3

Life-form 4

Life-form 5

Life-form 7

Life-form 6



2. Describe each characteristic as completely as you can. Based on your obser-vations, determine which of the life-forms are most alike.

3. Look at the data table below. Fill in the table according to the decisions youmade in step 2. State your reasons for the way you have grouped your life-forms.

Life-form Room AssignmentCompartment Life-forms Reasons

1

2

3

4. The USS Adventure has to make one more stop before returning home.On planet X437 you discover the most interesting life-form ever foundoutside of Earth—the CC9, shown at right. Make adecision, based on your previous grouping oflife-forms, about whether you can safely includeCC9 in one of the compartments for the trip to Earth.

ANALYZE THE RESULTS

1. Describe the life-forms in compartment 1. How are they similar? How are theydifferent?

2. Describe the life-forms in compartment 2. How are they similar? How do theydiffer from the life-forms in compartment 1?

Name Class Date

Voyage of the USS Adventure continued



3. Are there any life-forms in compartment 3? If so, describe their similarities. Inwhich compartment will you and your crewmates remain for the journey home?

DRAW CONCLUSIONS

4. Are you able to transport life-form CC9 safely back to Earth? If so, in whichcompartment will it be placed? How did you decide?

APPLYING YOUR DATA

In 1831, Charles Darwin sailed from England on a ship called the HMS Beagle.You have studied the finches that Darwin observed on the Galápagos Islands.What were some of the other unusual organisms he found there? For example,find out about the Galápagos tortoise.

Name Class Date



Holt Science and Technology 66 Bacteria and Viruses

Although viruses are made of only protein and nucleic acids, their structures havemany different shapes that help them attach to and invade living cells. One viralshape can be constructed from the template provided by your teacher. In thisactivity, you will construct and modify a model of a virus.

MATERIALS

SAFETY INFORMATION

PROCEDURE

1. Obtain a virus model template from your teacher. Carefullycopy the template on a piece of construction paper. You maymake the virus model as large as your teacher allows.

2. Plan how you will modify your virus. For example, youmight want to add the tail and tail fibers of a bacteriophageor wrap the model in plastic to represent the envelope thatsurrounds the protein coat in HIV.

3. Color your virus model, and cut it out by cutting on thesolid black lines. Then, fold the virus model along thedotted lines.

4. Glue or tape each lettered tab under the correspondinglettered triangle. For example, glue or tape the large Ztab under the Z-shaded triangle. When you are fin-ished, you should have a closed box with 20 sides.

5. Apply the modifications that you planned. Give your virus a name, and write iton the model. Decorate your classroom with your virus and those of yourclassmates.

ANALYZE THE RESULTS

1. Describe the modifications you made to your virus model, and explain howthe virus might use them.

Name Class Date

Viral DecorationsModel-Making Lab DATASHEET FOR LABBOOK

• glue (or tape)

• markers, colored

• paper, construction

• pipe cleaners, twist ties, buttons, string,plastic wrap, and other scrap materialsfor making variations of the virus

• scissors

• virus model template



2. If your virus causes disease, explain what disease it causes, how itreproduces, and how the virus is spread.

COMMUNICATING YOUR DATA

Research in the library or on the Internet an unusual virus that causes an illness,such as the influenza virus, HIV, or Ebola virus. Write a paragraph explainingwhat is unusual about the virus, what illness it causes, and how it might beavoided.

Name Class Date

Viral Decorations continued


Holt Science and Technology 72 Protists and Fungi

You have studied many of the diverse species of organisms within the kingdomProtista. This may be the first time you have ever seen many of these single-celled eukaryotes. In this activity, you will have an opportunity to express a bit ofcreativity by using what you have learned about these interesting organisms.

MATERIALS

• clothes hanger, wire


• paper (heavyweight construction paper or poster board)

• recycled material of your choice

• scissors

• string, yarn, lightweight wire, or fishing line

• tape, transparent (or glue)

SAFETY INFORMATION

PROCEDURE

1. Research the different kinds of protists you have studied. You may cut outpictures of them from magazines, or you may find examples of protists on theInternet. You may want to investigate Plasmodium, Euglena, amoebas, slimemolds, Radiolaria, Paramecium, Foraminifera, various other protozoans, oreven algae.

2. Using the paper and recycled materials, make a model of each protist youwant to include on your mobile. Be sure to include the special features ofeach protist, such as vacuoles, pseudopods, shells, cilia, or flagella.

3. Use tape or glue to attach special features to give your protists a three-dimensional look.

4. Provide labels for your protist models. For each protist, provide its name,classification, method of movement (if any), method for obtaining food, andany other interesting facts you have learned about it.

5. Attach your protist models to the wire hanger with wire or string. Use tape orglue to attach your labels to each model.

Name Class Date

Making a Protist MobileModel-Making Lab DATASHEET FOR LABBOOK



ANALYZE THE RESULTS

1. What have you learned about the diversity of protists? Include at least threehabitats where protists may be found.


Choose a disease-causing protist. Write a report describing the disease, its effecton people or the environment, and the efforts being made to control it.

Name Class Date

Making a Protist Mobile continued


Holt Science and Technology 86 Introduction to Plants

Imagine you are a naturalist all alone on an expedition in a rain forest. You havefound several plants that you think have never been seen before. You must con-tact a botanist, a scientist who studies plants, to confirm your suspicion. Becausethere is no mail service in the rain forest, you must describe these species com-pletely and accurately by radio. The botanist must be able to draw the leaves ofthe plants from your description. In this activity, you will carefully describe fiveplant specimens by using the examples and vocabulary lists in this lab.

MATERIALS

• gloves, protective • plant guidebook (optional)

• leaf specimens (5)

SAFETY INFORMATION

PROCEDURE

1. Examine the leaf characteristics illustrated on the pages for this lab in yourtextbook. You will notice that more than one term is needed to completelydescribe a leaf. The first leaf shown in the textbook has been labeled for youusing the examples and vocabulary lists found in this lab.

2. On a sheet of paper, draw a diagram of a leaf from each plant specimen.

3. Next to each drawing, carefully describe the leaf. Include general characteris-tics, such as relative size and color. For each plant, identify the following: leafshape, stem type, leaf arrangement, leaf edge, vein arrangement, and leaf-baseshape. Use the terms and vocabulary lists provided to describe each leaf asaccurately as possible and to label your drawings.

ANALYZE THE RESULTS

1. What is the difference between a simple leaf and a compound leaf?

2. Describe two different vein arrangements in leaves.

Name Class Date

Leaf Me Alone!Skills Practice Lab DATASHEET FOR LABBOOK



3. Based on what you know about adaptation, explain why there are so manydifferent leaf variations.


Choose a partner. Using the keys and vocabulary in this lab, describe a leaf, andsee if your partner can draw the leaf from your description. Switch roles, and seeif you can draw a leaf from your partner’s description.

Name Class Date

Leaf Me Alone! continued

LEAF SHAPES VOCABULARY LIST

cordate—heart shaped

lanceolate—sword shaped

lobate—lobed

oblong—rounded at the tip

orbicular—disk shaped

ovate—oval shaped, widest at base ofleaf

peltate—shield shaped

reniform—kidney shaped

sagittate—arrow shaped

STEMS VOCABULARY LIST

herbaceous—green, nonwoody stems

woody—bark or barklike covering onstem

LEAF ARRANGEMENTS VOCABULARY LIST

alternate—alternating leaves orleaflets along stem or petiole

compound—leaf divided into seg-ments, or several leaflets on a petiole

opposite—compound leaf with severalleaflets arranged oppositely along apetiole

palmate—single leaf with veinsarranged around a center point

palmate compound—several leafletsarranged around a center point

petiole—leaf stalk

pinnate—single leaf with veinsarranged along a center vein

pinnate compound—several leafletson either side of a petiole

simple—single leaf attached to stemby a petiole


Holt Science and Technology 62 Plant Processes

You are trying to find a way to drain an area that is flooded with water pollutedwith fertilizer. You know that a plant releases water through the stomata in itsleaves. As water evaporates from the leaves, more water is pulled up from theroots through the stem and into the leaves. By this process, called transpiration,

water and nutrients are pulled into the plant from the soil. About 90% of thewater a plant takes up through its roots is released into the atmosphere as watervapor through transpiration. Your idea is to add plants to the flooded area thatwill transpire the water and take up the fertilizer in their roots.

How much water can a plant take up and release in a certain period of time?In this activity, you will observe transpiration and determine one stem’s rate oftranspiration.

MATERIALS

SAFETY INFORMATION

PROCEDURE

1. Use the data table below for recording your measurements.

Height of Water in Test Tubes

2. Fill each test tube approximately three-fourths full of water. Place both testtubes in a test-tube rack.

3. Place the plant stem so that it stands upright in one of the test tubes.

Name Class Date

Weepy WeedsSkills Practice Lab DATASHEET FOR LABBOOK

• clock

• coleus or other plant stem cutting

• glass-marking pen

• metric ruler

• paper, graph

• test tube (2)

• test-tube rack

• water

Test tube Test tubeTime with plant without plant

Initial

After 10 min

After 20 min

After 30 min

After 40 min

Overnight



4. Use the glass-marking pen to mark the water level in each of the test tubes.Be sure you have the plant stem in place in its test tube before you mark thewater level. Why is this necessary?

5. Measure the height of the water in each test tube. Be sure to hold the testtube level, and measure from the waterline to the bottom of the curve at thebottom of the test tube. Record these measurements on the row labeled“Initial.”

6. Wait 10 min, and measure the height of the water in each test tube again.Record these measurements in your data table.

7. Repeat step 6 three more times. Record your measurements each time.

8. Wait 24 hours, and measure the height of the water in each test tube. Recordthese measurements in your data table.

9. Use the graph tothe right to plotthe data fromyour data table.Draw a line foreach test tube.Use a differentcolor for eachline.

10. Calculate the rateof transpirationfor your plant byusing the follow-ing operations:

Name Class Date

Weepy Weeds continued

0 10 20 30 40

102030405060708090100

Time (min)

Hei

ght

of w

ater

in

test

tub

e (m

m)

Test tube with plant:

Initial height– Overnight height

Difference in height of water (A)

Test tube without plant:


Difference in height of water (B)

Water height differencedue to transpiration:

Difference A– Difference B

Water lost due totranspiration (in millimeters) in 24 hours

Rate of Transpiration

red—test tube without plantblue—test tube with plant



ANALYZE THE RESULTS

1. What was the purpose of the test tube that held only water?

2. What caused the water to go down in the test tube containing the plant stem?Did the same thing happen in the test tube with water only? Explain youranswer.

3. What was the calculated rate of transpiration per day?

4. Using your graph, compare the rate of transpiration with the rate ofevaporation alone.

5. Prepare a presentation of your experiment for your class. Use your datatables, graphs, and calculations as visual aids.

APPLYING YOUR DATA

How many leaves did your plant sprigs have? Use this number to estimate whatthe rate of transpiration might be for a plant with 200 leaves. When you have youranswer in millimeters of height in a test tube, pour this amount into a graduatedcylinder to measure it in milliliters.

Name Class Date



Holt Science and Technology 70 Animals and Behavior

Earthworms have been digging in the Earth for more than 100 million years!Earthworms fertilize the soil with their waste and loosen the soil when they tun-nel through the moist dirt of a garden or lawn. Worms are food for many animals,such as birds, frogs, snakes, rodents, and fish. Some say they are good food forpeople, too!

In this activity, you will observe the behavior of a live earthworm. Rememberthat earthworms are living animals that deserve to be handled gently. Be sure tokeep your earthworm moist during this activity. The skin of the earthworm muststay moist so that the worm can get oxygen. If the earthworm’s skin dries out, theworm will suffocate and die. Use a spray bottle to moisten the earthworm withwater.

MATERIALS

SAFETY INFORMATION

PROCEDURE

1. Place a wet paper towel in the bottom of a dissecting pan. Put a live earth-worm on the paper towel, and observe how the earthworm moves. Recordyour observations.

2. Use the probe to carefully touch the anterior end (head) of the worm. Gentlytouch other areas of the worm’s body with the probe. Record the kinds ofresponses you observe.

3. Place celery leaves at one end of the pan. Record how the earthwormresponds to the presence of food.

4. Shine a flashlight on the anterior end of the earthworm. Record the earth-worm’s reaction to the light.

5. Line the bottom of the shoe box with a damp paper towel. Cover half of theshoe box with the box top.

6. Place the worm on the uncovered side of the shoe box in the light. Recordyour observations of the worm’s behavior for 3 min.

7. Place the worm in the covered side of the box. Record your observations for3 min.

Name Class Date

Wet, Wiggly Worms!Skills Practice Lab DATASHEET FOR LABBOOK

• celery leaves

• clock

• dissecting pan

• earthworm, live

• flashlight

• paper towels

• probe

• ruler, metric

• shoe box, with lid

• soil

• spray bottle

• water



8. Repeat steps 6–7 three times.

9. Spread some loose soil evenly in the bottom of the shoe box so that the soil isabout 4 cm deep. Place the earthworm on top of the soil. Observe and recordthe earthworm’s behavior for 3 min.

10. Dampen the soil on one side of the box, and leave the other side dry. Placethe earthworm in the center of the box between the wet and dry soil. Coverthe box, and wait 3 min. Uncover the box, and record your observations.Repeat this procedure three times. (You may need to search for the worm!)

ANALYZE THE RESULTS

1. How did the earthworm respond to being touched? Were some areas moresensitive than others?

2. How did the earthworm respond to the presence of food?

DRAW CONCLUSIONS

3. How is the earthworm’s behavior influenced by light? Based on your observations, describe how an animal’s response to a stimulus might provideprotection for the animal.

4. When the worm was given a choice of wet or dry soil, which did it choose?Explain this result.

Name Class Date

Wet, Wiggly Worms! continued




Based on your observations of an earthworm’s behavior, prepare a poster showing where you might expect to find earthworms. Draw a picture with col-ored markers, or cut out pictures from magazines. Include all the variables thatyou used in your experiment, such as soil or no soil, wet or dry soil, light or dark,and food. Write a caption at the bottom of your poster describing where earth-worms might be found in nature.

Name Class Date



Holt Science and Technology 76 Invertebrates

Insects are a special class of invertebrates with more than 750,000 knownspecies. Insects may be the most successful group of animals on Earth. In thisactivity you will observe a cricket’s structure and the simple adaptive behaviorsthat help make it so successful. Remember, you will be handling a living animalthat deserves to be treated with care.

MATERIALS

SAFETY INFORMATION

PROCEDURE

1. Place a cricket in a clean 600 mL beaker, and quickly cover the beaker withplastic wrap. The supply of oxygen in the container is enough for the cricketto breathe while you complete your work.

2. While the cricket is getting used to the container, look at the data table below.

CRICKET BODY STRUCTURES

3. Without making much movement, begin to examine the cricket. Fill in yourdata table with your observations of the cricket’s structure.

4. Place a small piece of apple in the beaker. Set the beaker on a table. Sitquietly for several minutes and observe the cricket. Any movement may causethe cricket to stop what it is doing. Record your observations.

5. Remove the plastic wrap from the beaker, remove the apple, and quicklyattach a second beaker. Join the two beakers together at the mouths withmasking tape. Handle the beakers carefully. Remember, there is a livinganimal inside.

Name Class Date

The Cricket CaperSkills Practice Lab DATASHEET FOR LABBOOK

• aluminum foil

• apple

• bags, plastic, sealable (2)

• beaker, 600 mL (2)

• cricket (2)

• hand lens (optional)

• ice, crushed

• lamp

• plastic wrap

• tape, masking

• water, tap, hot

Number Description

Body segments

Antennae

Eyes

Wings



6. Wrap one of the joined beakers with aluminum foil.

7. If the cricket is hiding under the aluminum foil, gently tap the sides of thebeaker until the cricket is exposed. Lay the joined beakers on their sides, andshine a lamp on the uncovered side. Record the cricket’s location.

8. Record the cricket’s location after 5 min. Without disturbing the cricket,carefully move the aluminum foil to the other beaker. After 5 min, record thecricket’s location. Repeat this process one more time to see if you get thesame result.

9. Fill a sealable plastic bag halfway with crushed ice. Fill another bag halfwaywith hot tap water. Seal each bag, and arrange them side by side on the table.

10. Remove the aluminum foil from the beakers. Gently rock the joined beakersfrom side to side until the cricket is in the center. Place the beakers on theplastic bags, as shown in the LabBook in the textbook.

11. Observe the cricket’s behavior for 5 min. Record your observations.

12. Set the beakers on one end for several minutes to allow them to return toroom temperature. Repeat steps 10–12 three times. (Why do you think it isnecessary to allow the beakers to return to room temperature each time?)

13. Set the beakers on one end. Carefully remove the masking tape, and separatethe beakers. Quickly replace the plastic wrap over the beaker containing thecricket. Allow your cricket to rest while you read through the two data tableson the following page.

14. Observe the cricket’s movement in the beaker every 15 seconds for 3 min. Fillin the Cricket (alone) data table using the following codes: 0 � no movement,1 � slight movement, and 2 � rapid movement.

15. Obtain a second cricket from your teacher, and place this cricket in thecontainer with the first cricket. Every 15 seconds, record the movement ofeach cricket in the Cricket A and Cricket B data table using the codes given instep 14.

ANALYZE THE RESULTS

1. Describe crickets’ feeding behavior. Are they lappers, suckers, or chewers?

Name Class Date

The Cricket Caper continued



CRICKET (alone) CRICKET A AND CRICKET B

2. Do crickets prefer light or darkness? Explain.

3. From your observations, what can you infer about a cricket’s temperaturepreferences?

DRAW CONCLUSIONS

4. Based on your observations of Cricket A and Cricket B, what generalstatements can you make about the social behavior of crickets?

Name Class Date


15 s

30 s

45 s

60 s

75 s

90 s

105 s

120 s

135 s

150 s

165 s

180 s

A B

15 s

30 s

45 s

60 s

75 s

90 s

105 s

120 s

135 s

150 s

165 s

180 s



APPLYING YOUR DATA

Make a third data table titled “Cricket and Another Species of Insect.” Introduceanother insect, such as a grasshopper, into the beaker. Record your observationsfor 3 min. Write a short summary of the cricket’s reaction to another species.

Name Class Date



Holt Science and Technology 65 Fishes, Amphibians, and Reptiles

Imagine that you are a scientist interested in amphibians. You have heard in thenews about amphibians disappearing all over the world. What a great loss it willbe to the environment if all amphibians become extinct! Your job is to learn asmuch as possible about how frogs normally behave so that you can act as aresource for other scientists who are studying the problem. In this activity, youwill observe a normal frog in a dry container and in water.

MATERIALS

SAFETY INFORMATION

PROCEDURE

1. In the following table, note all of your observations of the frog in thisinvestigation.

Name Class Date

A Prince of a FrogSkills Practice Lab DATASHEET FOR LABBOOK

• beaker, 600 mL

• container half-filled withdechlorinated water

• crickets, live

• frog, live, in a dry container

• gloves, protective

• rock, large (optional)

Characteristic Observation

Breathing

Eyes

Legs

Response to food

Skin texture

Swimming behavior

Skin coloration



OBSERVATIONS OF A LIVE FROG

2. Observe a live frog in a dry container. Draw a picture of the frog. Label theeyes, nostrils, front legs, and hind legs.

3. Watch the frog’s movements as it breathes air with its lungs. Write a descrip-tion of the frog’s breathing.

4. Look closely at the frog’s eyes, and note their location. Examine the upperand lower eyelids as well as the transparent third eyelid. Which of these threeeyelids actually moves over the eye?

5. Study the frog’s legs. Note in your data table the difference between the frontand hind legs.

6. Place a live insect, such as a cricket, in the container. Observe and recordhow the frog reacts.

7. Carefully pick up the frog, and examine its skin. How does it feel? Caution:

Remember that a frog is a living thing and deserves to be handled gently andwith respect.

8. Place a 600 mL beaker in the container. Place the frog in the beaker. Coverthe beaker with your hand, and carry it to a container of dechlorinated water.Tilt the beaker and gently submerge it in the water until the frog swims out ofthe beaker.

9. Watch the frog float and swim in the water. How does the frog use its legs toswim? Notice the position of the frog’s head.

10. As the frog swims, bend down and look up into the water so that you can seethe underside of the frog. Then look down on the frog from above. Comparethe color on the top and the underneath sides of the frog. Record your observations in your data table.

ANALYZE THE RESULTS

1. From the position of the frog’s eyes, what can you infer about the frog’s fieldof vision? How might the position of the frog’s eyes benefit the frog while it isswimming?

2. How can a frog “breathe” while it is swimming in water?

Name Class Date

A Prince of a Frog continued



3. How are the hind legs of a frog adapted for life on land and in water?

4. What differences did you notice in coloration on the frog’s top side and itsunderneath side? What advantage might these color differences provide?

5. How does the frog eat? What senses are involved in helping the frog catch itsprey?

APPLYING YOUR DATA

Observe another type of amphibian, such as a salamander. How do theadaptations of other types of amphibians compare with those of the frog youobserved in this investigation?

Name Class Date



Holt Science and Technology 69 Interactions of Living Things

Since the beginning of life on Earth, species have had special characteristicscalled adaptations that have helped them survive changes in environmental con-ditions. Changes in a species’ environment include climate changes, habitatdestruction, or the extinction of prey. These things can cause a species to die outunless the species has a characteristic that helps it survive. For example, aspecies of bird may have an adaptation for eating sunflower seeds and ants. If theant population dies out, the bird can still eat seeds and can therefore survive. Inthis activity, you will explore several adaptations and design an organism withadaptations you choose. Then, you will describe how these adaptations help theorganism survive.

MATERIALS

SAFETY INFORMATION

PROCEDURE

1. Study the chart below. Choose one adaptation from each column. Forexample, an organism might be a scavenger that burrows undergroundand has spikes on its tail!

Adaptations

Name Class Date

Adaptation: It’s a Way of LifeModel-Making Lab DATASHEET FOR LABBOOK

Diet Type of transportation Special adaptation

carnivore flies uses sensors to detect heat

herbivore glides through the air is active only at night and has excellent night vision

omnivore burrows underground changes colors to match its surroundings

scavenger runs fast has armor

decomposer swims has horns

hops can withstand extreme temperature changes

walks secretes a terrible and sickening scent

climbs has poison glands

floats has specialized front teeth

slithers has tail spikes

stores oxygen in its cells so it does not have tobreathe continuously

one of your own invention

• arts-and-crafts materials, various


• magazines for cutouts

• poster board

• scissors



2. Design an organism that has the three adaptations you have chosen. Useposter board, colored markers, picture cutouts, or craft materials of yourchoosing to create your organism.

3. Write a caption on your poster describing your organism. Describe its appear-ance, its habitat, its niche, and the way its adaptations help it survive. Giveyour organism a two-part “scientific” name that is based on its characteristics.

4. Display your creation in your classroom. Share with classmates how youchose the adaptations for your organism.

ANALYZE THE RESULTS

1. What does your imaginary organism eat?

2. In what environment or habitat would your organism be most likely to sur-vive—in the desert, tropical rain forest, plains, icecaps, mountains, or ocean?Explain your answer.

3. Is your creature a mammal, a reptile, an amphibian, a bird, or a fish? Whatmodern organism (on Earth today) or ancient organism (extinct) is yourimaginary organism most like? Explain the similarities between the twoorganisms. Do some research outside the lab, if necessary, to find out about areal organism that may be similar to your imaginary organism.

DRAW CONCLUSIONS

4. If there were a sudden climate change, such as daily downpours of rain in adesert, would your imaginary organism survive? What adaptations for surviv-ing such a change does it have?

Name Class Date

Adaptation: It’s a Way of Life continued



APPLYING YOUR DATA

Call or write to an agency such as the U.S. Fish and Wildlife Service to get a listof endangered species in your area. Choose an organism on that list.Describe the organism’s niche and any special adaptations it has that help it survive. Find out whyit is endangered and what is being done toprotect it. Examine the illustration of theanimal at right. Based on its physicalcharacteristics, describe its habitat andniche. Is this a real animal?

Name Class Date



Holt Science and Technology 52 Cycles in Nature

Succession is the natural process of the introduction and development of livingthings in an area. The area could be one that has never supported life before andhas no soil, such as a recently cooled lava flow from a volcano. In an area wherethere is no soil, the process is called primary succession. In an area where soilalready exists, such as an abandoned field or a forest after a fire, the process iscalled secondary succession. In this investigation, you will build a model of sec-ondary succession using natural soil.

MATERIALS

SAFETY INFORMATION

PROCEDURE

1. Place the natural soil you brought from home or the schoolyard into thefishbowl, and dampen the soil with 250 mL of water. Cover the top of thefishbowl with plastic wrap, and place the fishbowl in a sunny window.Caution: Do not touch your face, eyes, or mouth during this activity. Washyour hands thoroughly when you are finished.

2. For 2 weeks, observe the fishbowl for any new growth. Describe and drawany new organisms you observe. Record these and all other observations.

3. Identify and record the names of as many of these new organisms as you can.

ANALYZE THE RESULTS

1. What kinds of plants sprouted in your model of secondary succession? Werethey tree seedlings, grasses, or weeds?

Name Class Date

A Passel o’ PioneersModel-Making Lab DATASHEET FOR LABBOOK

• balance

• graduated cylinder, 250 mL

• large fishbowl

• plastic wrap

• protective gloves

• soil from home or schoolyard, 500 g

• water, 250 mL



2. Were the plants that sprouted in the fishbowl unusual or common for yourarea?

DRAW CONCLUSIONS

3. Explain how the plants that grew in your model of secondary succession canbe called pioneer species.

APPLYING YOUR DATA

Examine each of the photographs from the pages for this lab in your textbook.Determine whether each area, if abandoned forever, would undergo primary orsecondary succession. You may decide that an area will not undergo successionat all. Explain your reasoning.

Name Class Date

A Passel o’ Pioneers continued


Holt Science and Technology 67 The Earth’s Ecosystems

Organisms that live in the desert have some unusual methods for conservingwater. Conserving water is a special challenge for animals that live in the desert.In this activity you will invent a water-conserving “adaptation” for a desert animal, represented by a piece of sponge. You will protect your wet desertsponge so it will dry out as little as possible over a 24 h period.

MATERIALS

ASK A QUESTION

1. How can an animal conserve water in the desert?

FORM A HYPOTHESIS

2. Plan a method for keeping your “desert animal” from drying out. Your “animal” must be in the open for at least 4 h during the 24 h period. Realdesert animals expose themselves to the dry desert heat to search for food.Write your plan and predictions about the outcome of your experiment.

3. Design and draw data tables, if necessary. Have your teacher approve yourplan before you begin.

TEST THE HYPOTHESIS

4. Soak two pieces of sponge in water until they begin to drip. Place each pieceon a balance, and record its mass.

5. Immediately protect one sponge according to your plan. Place both pieces inan area where they will not be disturbed. You should take your protected“animal” out for feeding for a total of at least 4 h.

6. At the end of 24 h, place each piece of sponge on the balance again, andrecord its mass.

Name Class Date

Life in the DesertInquiry Lab DATASHEET FOR LABBOOK

• balance

• sponge, dry, 8 cm � 8 cm � 2 cm (2 pieces)

• water

• other materials as needed

Using Scientific Methods



ANALYZE THE RESULTS

1. Describe the adaptation you used to help your “animal” survive. Was it effective? Explain.

2. What was the purpose of leaving one of the sponges unprotected? How didthe water loss in each of your sponges compare?


Conduct a class discussion about other adaptations and results. How can yourelate these invented adaptations to adaptations for desert survival among realorganisms?

Name Class Date

Life in the Desert continued



In your study of ecosystems, you learned that a biome is a very large ecosystemthat includes a set of smaller, related ecosystems. For example, a coniferous forest biome may include a river ecosystem, a wetland ecosystem, and a lakeecosystem. Each of those ecosystems may include several other smaller, relatedecosystems. Even cities have mini-ecosystems! You may find a mini-ecosystem ona patch of sidewalk, in a puddle of rainwater, under a leaky faucet, in a shadyarea, or under a rock. In this activity, you will design a method for comparing twodifferent mini-ecosystems found near your school.

MATERIALS

• items to be determined by the students and approved by the teacher

SAFETY INFORMATION

ASK A QUESTION

1. Examine the grounds around your school, and select two different areas youwish to investigate. Decide what you want to learn about your mini-ecosystems.For example, you may want to know what kind of living things each areacontains. Be sure to get your teacher’s approval before you begin.

FORM A HYPOTHESIS

2. For each mini-ecosystem, make data tables for recording your observations.

Name Class Date

Discovering Mini-EcosystemsInquiry Lab DATASHEET FOR LABBOOK




TEST THE HYPOTHESIS

3. Observe your mini-ecosystem according to your plan at several different timepoints throughout the day. Record your observations.

4. Wait 24 h and observe your mini-ecosystem again at the same times that youobserved it the day before. Record your observations.

5. Wait 1 week, and observe your mini-ecosystem again at the same times.Record your observations.

ANALYZE THE RESULTS

1. What factors determine the differences between your mini-ecosystems? Identifythe factors that set each mini-ecosystem apart from its surrounding area.

2. How do the populations of your mini-ecosystems compare?

3. Identify some of the adaptations that the organisms living in your two mini-ecosystems have. Describe how the adaptations help the organisms survive intheir environment.

DRAW CONCLUSIONS

4. Write a report describing and comparing your mini-ecosystems with those ofyour classmates.

Name Class Date

Discovering Mini-Ecosystems continued


Holt Science and Technology 62 Environmental Problems and Solutions

You make hundreds of decisions every day. Some of them are complicated, butmany of them are very simple, such as what to wear or what to eat for lunch.Deciding what to do about an environmental issue can be very difficult. There aremany different factors that must be considered. How will a certain solution affectpeople’s lives? How much will it cost? Is it ethically right?

In this activity, you will analyze an issue in four steps to help you make a decision about it. Find out about environmental issues that are being discussed inyour area. Examine newspapers, magazines, and other publications to find outwhat the issues are. Choose one local issue to evaluate. For example, you couldevaluate whether the city should spend the money to provide recycling bins andspecial trucks for picking up recyclable trash.

MATERIALS

• newspapers, magazines, and other publicationscontaining information about environmental issues

PROCEDURE

1. Write a statement about an environmental issue.

2. Read about your issue in several publications. Ona separate sheet of paper, summarize importantfacts.

3. The values of an issue are the things that youconsider important. Examine the diagram below.Several values are given. Which values do you think apply most to the envi-ronmental issue you are considering? Are there other values that you believewill help you make a decision about the issue? Consider at least four values inmaking your decision.

Name Class Date

Deciding About Environmental IssuesSkills Practice Lab DATASHEET FOR LABBOOK

Environmentaldecisions

What is beautifulor pleasing

Provides funactivities

Knowledge gainedby research

Respects traditionsof a community

Affects people'shealth

What is rightor wrong

Protects naturalresources

Gain or loss ofmoney or jobs

A Four-StepDecision-Making Model

Gather Information

▼Consider Values

▼Explore Consequences

▼Make a Decision



4. Consequences are the things that result from a certain course of action. Createa table similar to the one below. Use the data table below to organize yourthoughts about consequences related to your environmental issue. List yourvalues at the top. Fill in each space with the consequences for each value.

Consequences TableValues

Consequences

Positive short-termconsequences

Negative short-termconsequences

Positive long-termconsequences

Negative long-termconsequences

5. Thoroughly consider all of the consequences you have recorded in your table.Evaluate how important each consequence is. Make a decision about whatcourse of action you would choose on the issue.

ANALYZE THE RESULTS

1. In your evaluation, did you consider short-term consequences or long-termconsequences to be more important? Why?

2. Which value or values had the greatest influence on your final decision?Explain your reasoning.


Compare your table with your classmates’ tables. Did you all make the same deci-sion about a similar issue? If not, form teams, and organize a formal classroomdebate of a specific environmental issue.

Name Class Date

Deciding About Environmental Issues continued


Holt Science and Technology 73 Body Organization and Structure

Have you ever exercised outside on a cold fall day wearing only a thin warm-upsuit or shorts? How did you stay warm? The answer is that your muscle cells contracted, and when contraction takes place, some energy is used to do work,and the rest is converted to thermal energy. This process helps your bodymaintain a constant temperature in cold conditions. In this activity, you will learnhow the release of energy can cause a change in your body temperature.

MATERIALS


• thermometer, small, hand held

• other materials as approved by your teacher

ASK A QUESTION

1. Write a question that you can test about how activity affects body temperature.

FORM A HYPOTHESIS

2. Form a group of four students. In your group, discuss several exercises thatcan produce a change in body temperature. Write a hypothesis that couldanswer the question you asked.

TEST THE HYPOTHESIS

3. Develop an experimental procedure that includes the steps necessary to testyour hypothesis. Be sure to get your teacher’s approval before you begin.

4. Assign tasks to individuals in the group, such as note taking, data recording,and timing. What observations and data will you be recording? Design yourdata tables accordingly.

5. Perform your experiment as planned by your group. Be sure to record allobservations in your data tables.

Name Class Date

Muscles at WorkInquiry Lab DATASHEET FOR LABBOOK




ANALYZE THE RESULTS

1. How did you determine if muscle contractions cause the release of thermalenergy? Was your hypothesis supported by your data? Explain your results ina written report. Describe how you could improve your experimental method.

APPLYING YOUR DATA

Why do humans shiver in the cold? Do all animals shiver? Find out why shiveringis one of the first signs that your body is becoming too cold.

Name Class Date

Muscles at Work continued


Holt Science and Technology 77 Circulation and Respiration

When you breathe, you actually pull air into your lungs because your diaphragmmuscle causes your chest to expand. You can see this is true by placing yourhands on your ribs and inhaling slowly. Did you feel your chest expand? In thisactivity, you will build a model of a lung by using some common materials. Youwill see how the diaphragm muscle works to inflate your lungs. Refer to the diagrams in the textbook as you construct your model.

MATERIALS

PROCEDURE

1. Attach the balloon to the end of the straw with a rubber band. Make a holethrough the clay, and insert the other end of the straw through the hole. Besure at least 8 cm of the straw extends beyond the clay. Squeeze the ball ofclay gently to seal the clay around the straw.

2. Insert the balloon end of the straw into the neck of the bottle. Use the ball ofclay to seal the straw and balloon into the bottle.

3. Turn the bottle gently on its side. Place the trash bag over the cut end of thebottle. Expand a rubber band around the bottom of the bottle to secure thebag. You may wish to reinforce the seal with tape. Before the plastic is completely sealed, gather the excess material of the bag into your hand, andpress toward the inside of the bottle slightly. (You may need to tie a knotabout halfway up from the bottom of the bag to take up excess material.) Usetape to finish sealing the bag to the bottle with the bag in this position. Theexcess air will be pushed out of the bottle.

ANALYZE THE RESULTS

1. What can you do with your model to make the “lung” inflate?

2. What do the balloon, the plastic wrap, and the straw represent in your model?

Name Class Date

Build a LungModel-Making Lab DATASHEET FOR LABBOOK

• bag, trash, small plastic

• balloon, small

• bottle, top half, 2 L

• clay, golf-ball-sized piece

• rubber bands (2)

• ruler, metric

• straw, plastic

• tape, transparent



3. Using your model, demonstrate to the class how air enters the lung and howair exits the lung.

APPLYING YOUR DATA

Do some research to find out what an “iron lung” is and why it was used in thepast. Research and write a report about what is used today to help people whohave difficulty breathing.

Name Class Date

Build a Lung continued

You know how important enzymes are in the process of digestion. This lab willhelp you see enzymes at work. Hydrogen peroxide is continuously produced byyour cells. If it is not quickly broken down, hydrogen peroxide will kill your cells.Luckily, your cells contain an enzyme that converts hydrogen peroxide into twononpoisonous substances. This enzyme is also present in the cells of beef liver. Inthis lab, you will observe the action of this enzyme on hydrogen peroxide.

MATERIALS

SAFETY INFORMATION

PROCEDURE

1. Use the data table below to record your observations.

Data Table

Size andcondition

ExperimentalObservations

of liver liquid

1 cm cubebeef liver 2 mL water

1 cm cube 2 mL hydrogenbeef liver peroxide

1 cm cube2 mL hydrogenbeef liver

peroxide(mashed)

2. Get three equal-sized pieces of beef liver from your teacher, and use yourforceps to place them on your plate.

3. Pour 2 mL of water into a test tube labeled “Water and liver.”

4. Using the tweezers, carefully place one piece of liver in the test tube. Recordyour observations in your data table.


Holt Science and Technology 56 The Digestive and Urinary Systems

Name Class Date

Enzymes in ActionSkills Practice Lab DATASHEET FOR LABBOOK

• beef liver, 1 cm cubes (3)



• hydrogen peroxide, fresh (4 mL)

• mortar and pestle (or fork and watchglass)

• plate, small

• spatula

• test tube (3)

• test-tube rack

• tweezers

• water



5. Pour 2 mL of hydrogen peroxide into a second test tube labeled “Liver andhydrogen peroxide.”

Caution: Do not splash hydrogen peroxide on your skin. If you do get hydro-gen peroxide on your skin, rinse the affected area with running water immedi-ately, and tell your teacher.

6. Using the tweezers, carefully place one piece of liver in the test tube. Recordyour observations of the second test tube in your data table.

7. Pour another 2 mL of hydrogen peroxide into a third test tube labeled“Ground liver and hydrogen peroxide.”

8. Using a mortar and pestle (or fork and watch glass), carefully grind the thirdpiece of liver.

9. Using the spatula, scrape the ground liver into the third test tube. Record yourobservations of the third test tube in your data table.

ANALYZE THE RESULTS

1. What was the purpose of putting the first piece of liver in water? Why wasthis a necessary step?

2. Describe the difference you observed between the liver and the ground liverwhen each was placed in the hydrogen peroxide. How can you account forthis difference?

Name Class Date

Enzymes in Action continued



APPLYING YOUR DATA

Do plant cells contain enzymes that break down hydrogen peroxide? Try thisexperiment using potato cubes instead of liver to find out.

Name Class Date



Holt Science and Technology 66 Reproduction and Development

In humans, the process of development that takes place between fertilization andbirth lasts about 266 days. In 4 weeks, the new individual grows from a single fer-tilized cell to an embryo whose heart is beating and pumping blood. All of theorgan systems and body parts are completely formed by the end of the seventhmonth. During the last 2 months before birth, the baby grows, and its organ sys-tems mature. At birth, the average mass of a baby is about 33,000 times as muchas that of an embryo at 2 weeks of development! In this activity, you will discoverjust how fast a fetus grows.

MATERIALS

• paper, graph

• pencils, colored

PROCEDURE

1. Using graph paper, make two graphs—one entitled “Length” and one entitled“Mass.”On the length graph, use intervals of 25 mm on the y-axis. Extend they-axis to 500 mm. On the mass graph, use intervals of 100 g on the y-axis.Extend this y-axis to 3,300 g. Use 2-week intervals for time on the x-axes forboth graphs. Both x-axes should extend to 40 weeks.

2. Examine the data table on the next page. Plot the data in the table on yourgraphs. Use a colored pencil to draw the curved line that joins the points oneach graph.

ANALYZE THE RESULTS

1. Describe the change in mass of a developing fetus. How can you explain thischange?

2. Describe the change in length of a developing fetus. How does the change inmass compare to the change in length?

Name Class Date

My, How You’ve Grown!Skills Practice Lab DATASHEET FOR LABBOOK



INCREASE OF MASS AND LENGTH OF AVERAGE HUMAN FETUS

Time (weeks) Mass (g) Length (mm)2 0.1 1.53 0.3 2.34 0.5 5.05 0.6 10.06 0.8 15.08 1.0 30.013 15.0 90.017 115.0 140.021 300.0 250.026 950.0 320.030 1,500.0 400.035 2,300.0 450.040 3,300.0 500.0

APPLYING YOUR DATA

Using the information in your graphs, estimate how tall a child would be at age 3if he or she continued to grow at the same average rate that a fetus grows.

Name Class Date

My, How You’ve Grown! continued


Holt Science and Technology 56 Body Defenses and Disease

Some cells of the immune system, called B cells, make antibodies that attack andkill invading viruses and microorganisms. These antibodies help make youimmune to disease. Have you ever had chickenpox? If you have, your body hasbuilt up antibodies that can recognize that particular virus. Antibodies will attachthemselves to the virus, tagging it for destruction. If you are exposed to the samedisease again, the antibodies remember that virus. They will attack the virus evenquicker and in greater number than they did the first time. This is the reason thatyou will probably never have chickenpox more than once. In this activity, youwill construct simple models of viruses and their antibodies. You will see howantibodies are specific for a particular virus.

MATERIALS

PROCEDURE

1. Draw the virus patterns shown on this page on a separate piece of paper, ordesign your own virus models from the craft supplies. Remember to designdifferent receptors on each of your virus models.

Name Class Date

Antibodies to the RescueModel-Making Lab DATASHEET FOR LABBOOK

• craft materials, such as buttons,fabric scraps, pipe cleaners, andrecycled materials

• paper, colored

• scissors

• tape (or glue)

B

C

Viruses

A Virus

Virus

Virus

Receptor

Receptor

Receptor



2. Write a few sentences describing how your viruses are different.

3. Cut out the viruses, and attach them to a piece of colored paper with tapeor glue.

4. Select the antibodies drawn below, or design your own antibodies that willexactly fit on the receptors on your virus models. Draw or create eachantibody enough times to attach one to each receptor site on the virus.

ANTIBODIES

5. Cut out the antibodies you have drawn. Arrange the antibodies so that theybind to the virus at the appropriate receptor. Attach them to the virus withtape or glue.

ANALYZE THE RESULTS

1. Explain how an antibody “recognizes” a particular virus.

Name Class Date

Antibodies to the Rescue continued



2. After the attachment of antibodies to the receptors, what would be the nextstep in the immune response?

3. Many vaccines use weakened copies of the virus to protect the body. Use themodel of a virus and its specific antibody to explain how vaccines work.

DRAW CONCLUSIONS

4. Use your model of a virus to demonstrate to the class how a receptor mightchange or mutate so that a vaccine would no longer be effective.

Name Class Date




APPLYING YOUR DATA

Research in the library or on the Internet to find information about the dis-covery of the Salk vaccine for polio. Include information on how polio affectspeople today.

Research in the library or on the Internet to find information and write areport about filoviruses. What do they look like? What diseases do they cause?Why are they especially dangerous? Is there an effective vaccine against anyfilovirus? Explain.

Name Class Date



Holt Science and Technology 73 Staying Healthy

There are six main classes of foods that we need in order to keep our bodiesfunctioning properly: water, vitamins, minerals, carbohydrates, fats, and proteins.In this activity you will investigate the importance of a well-balanced diet inmaintaining a healthy body. Then you will create a poster or picture that illus-trates the importance of one of the three energy-producing nutrients—carbohy-drates, fats, and proteins.

MATERIALS

PROCEDURE

1. Look at the table below. Research in the library, on nutrition labels, in nutri-tion or diet books, or on the Internet to find the information you need to fillout the chart.

NUTRITION DATA TABLE

Fats Carbohydrates Proteins

Found in which foods

Functions in the body

Consequences of deficiency

Name Class Date

To Diet or Not to DietSkills Practice Lab DATASHEET FOR LABBOOK

• crayons (or markers), assortedcolors

• diet books

• menus, fast-food (optional)

• nutrition reference books

• paper, white unlined



2. Choose one of the foods you have learned about in your research, and createa poster or picture that describes its importance in a well-balanced diet.

ANALYZE THE RESULTS

1. Based on what you have learned in this lab, how might you change youreating habits to have a well-balanced diet? Does the nutritional value of foodsconcern you? Why or why not? Write down your answers, and explain yourreasoning.


Write a paragraph explaining why water is a nutrient. Analyze a typical fast-foodmeal, and determine its overall nutritional value.

Name Class Date

To Diet or Not to Diet continued



Teacher Notes and Answer KeyTIME REQUIRED

One 45-minute class period

LAB RATINGSTeacher Prep–2Student Set-Up–1Concept Level–1Clean Up–1

SAFETY CAUTION

Caution students to exercise proper care when handling the beaker of hot water.Also, caution students to be careful when they are moving around an electricalcord. A clip that will hold the thermometer to the side of the beaker and off thebottom of the beaker while it is heating or cooling is safer and more accuratethan a thermometer simply propped up inside the beaker.


ANSWER KEY



Edith C. McAlanisSocorro Middle School

El Paso, Texas

1 2 3 4Easy Hard


Holt Science and Technology 72 The World of Life ScienceCopyright © by Holt, Rinehart and Winston. All rights reserved.


ANSWER KEY

When performing an experiment, you usually need to collect data. To understandthe data, you can often organize them into a graph. Graphs can show trends andpatterns that you might not notice in a table or list. In this exercise, you will prac-tice collecting data and organizing the data into a graph.

MATERIALS

SAFETY INFORMATION

PROCEDURE

1. Pour 200 mL of water into a 400 mL beaker. Add ice to the beaker until thewaterline is at the 400 mL mark.

2. Place a Celsius thermometer into the beaker. Use a thermometer clip toprevent the thermometer from touching the bottom of the beaker. Record thetemperature of the ice water.

3. Place the beaker and thermometer on a hot plate. Turn the hot plate onmedium heat, and record the temperature every minute until the water tem-perature reaches 100°C.

4. Using heat-resistant gloves, remove the beaker from the hot plate. Continue torecord the temperature of the water each minute for 10 more minutes.Caution: Don’t forget to turn off the hot plate.

5. On a piece of graph paper, create a graph similar to the one on the next page.Label the horizontal axis (the x-axis) “Time (min),” and mark the axis inincrements of 1 min as shown. Label the vertical axis (the y-axis)“Temperature (°C),” and mark the axis in increments of 10° as shown.

Name Class Date


• beaker, 400 mL



• hot plate

• ice

• paper, graph

• thermometer, Celsius, with a clip

• water, 200 mL



6. Find the 1 min mark on the x-axis, and move up the graph to the temperatureyou recorded at 1 min. Place a dot on the graph at that point. Plot each tem-perature in the same way. When you have plotted all of your data, connect thedots with a smooth line.

ANALYZE THE RESULTS

1. Examine your graph. Do you think the water heated faster than it cooled?Explain.

2. Estimate what the temperature of the water was 2.5 min after you placed thebeaker on the hot plate. Explain how you can make a good estimate of tem-perature between those you recorded.

DRAW CONCLUSIONS

3. Explain how a graph may give more information than the same data in a table.

ANSWER KEY



Name Class Date

Graphing Data continued

Answers may vary according to several factors, including altitude.

Answers may vary.

A list or a chart is organized information, and sometimes it is necessary to

put collected data into one of these forms before graphing. Because a graph

is like a picture, it can often help scientists to see what is happening when

numbers alone would be confusing. A graph can show a trend or a pattern

that may not be readily discernible in a list or chart.

0

1 2 3 4 5 6 7 8 9 10

10

20

30

40

50

60

70

80

90

100

11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

Time (min)

Tem

pera

ture

(°C

)




Two 45-minute class periods


MATERIALS

The materials listed on the student page are enough for a group of 3–4 students.Yeast is easily obtained from the local grocery store. The school cafeteria may bewilling to donate the amount you need. You may wish to add other materials inanticipation of students’ experimental design. For example, some students mayrecognize that they could collect CO2 in a balloon attached to the top of a testtube containing live yeast.

SAFETY CAUTION

Remind students to review all safety cautions and icons before beginning this labactivity. Caution students to be careful of the hot plate and the cord. You shoulddemonstrate the proper laboratory technique for determining the presence of anodor. Hold the container away from your face about 25 cm and just below yournose. Use the other hand to “waft” the odor toward your face. Caution studentsNEVER to put their noses directly in a container and inhale.

PREPARATION NOTES

At least one of the suspect samples should be killed yeast. To kill the yeast, placethe yeast in an oven at 400°F for 10 min or in a microwave oven for a few minutes at high power. Do not allow yeast to become moist before use.Toothpicks, coffee stirrers, and so on, may be used for stirring. The amounts ofeach ingredient used are not definite, and you may wish to vary amounts, depend-ing on the results desired.

LAB NOTES

To help students prepare for this activity, you may wish to review cellular respiration and fermentation. The equation for respiration follows:

C6H12O6 � 6O2 6CO2 � 6H2O � energy


ANSWER KEY



Susan GormanNorth Ridge Middle SchoolNorth Richland Hills, Texas

1 2 3 4Easy Hard


Holt Science and Technology 62 It’s Alive!! Or Is It?Copyright © by Holt, Rinehart and Winston. All rights reserved.


ANSWER KEY

The chief baker at the Best-Bread Bakery thinks that the yeast the bakeryreceived may be dead. Yeast is a central ingredient in bread. Yeast is a livingorganism, a member of the kingdom Fungi, and it undergoes the same lifeprocesses as other living organisms. When yeast grows in the presence of oxygenand other nutrients, yeast produces carbon dioxide. The gas forms bubbles thatcause bread dough to rise. Thousands of dollars may be lost if the yeast is dead.

The Best-Bread Bakery has requested that you test the yeast. The bakery hasfurnished samples of live yeast and some samples of the yeast in question.

MATERIALS

SAFETY INFORMATION

PROCEDURE

1. Use the table below to record your data.

Name Class Date


• beaker, 250 mL

• flour


• graduated cylinder

• hot plate

• magnifying lens

• scoopula (or small spoon)

• stirring sticks, wooden (3)

• sugar

• test-tube rack

• test tubes (3) (or clear plastic cups)

• thermometer, Celsius, with clip

• water, 125 mL

• yeast samples (live, A, and B)

DeadYeast 0 5 10 15 20 25 orSample Observations min min min min min min alive?

Live

Sample A

Sample B

Answers are based on students’ observations and may vary.



2. Examine each yeast sample with a magnifying lens. You may want to sniff thesamples to determine the presence of an odor. (Your teacher will demonstratethe appropriate way to detect odors in this lab.) Record your observations inthe data table.

3. Label three test tubes or plastic cups “Live Yeast,” “Sample A Yeast,” and“Sample B Yeast.”

4. Fill a beaker with 125 mL of water, and place the beaker on a hot plate. Use athermometer to be sure the water does not get warmer than 32°C. Attach thethermometer to the side of the beaker with a clip so the thermometer doesn’ttouch the bottom of the beaker. Turn off the hot plate when the water temperature reaches 32°C.

5. Add a small scoop (about 1/2 tsp) of each yeast sample to the correctlylabeled container. Add a small scoop of sugar to each container.

6. Add 10 mL of the warm water to each container, and stir.

7. Add a small scoop of flour to each container, and stir again. The flour willhelp make the process more visible but is not necessary as food for the yeast.

8. Observe the samples carefully. Look for bubbles. Make observations at 5 min intervals. Write your observations in the data table.

9. In the last column of the data table, write “alive” or “dead” based on yourobservations during the experiment.

ANALYZE THE RESULTS

1. Describe any differences in the yeast samples before the experiment.

2. Describe the appearance of the yeast samples at the conclusion of the experiment.

3. Why was a sample of live yeast included in the experiment?

ANSWER KEY



Name Class Date


Answers are based on students’ observations and may vary.

Sample answer: Live yeast was included so that bubble formation from the

respiration of living organisms could be observed.

Answers may vary.



4. Why was sugar added to the samples?

5. Based on your observations, is either Sample A or Sample B alive?

DRAW CONCLUSIONS

6. Write a letter to the Best-Bread Bakery stating your recommendation to use ornot use the yeast samples. Give reasons for your recommendation.

APPLYING YOUR DATA

Based on your observations of the nutrient requirements of yeast, design anexperiment to determine the ideal combination of nutrients. Vary the amount ofnutrients, or examine different energy sources.

ANSWER KEY



Name Class Date


Sugar was added as a nutrient for the living yeast.

Answers may vary according to students’ experimental protocol.

Student letters may vary but should recommend the optimal samples they

determined in their experiment.



Teacher Notes and Answer Key

TIME REQUIRED


RATING

Teacher Prep–1

Student Set-Up–1

Concept Level–1

Clean Up–1

SAFETY INFORMATION

MATERIALS

The materials listed on the student page are enough for a group of 3–4 students.Be sure to keep the algae in a warm, damp place out of direct sunlight; a closedplastic bag with water sprayed into it is ideal.


ANSWER KEY



Terry RakesElmwood Junior High School

Rogers, Arkansas


Holt Science and Technology 67 Cells: The Basic Units of LifeCopyright © by Holt, Rinehart and Winston. All rights reserved.


ANSWER KEY

You have probably used a microscope to look at single-celled organisms. Theycan be found in pond water. In the following exercise, you will look atProtococcus—algae that form a greenish stain on tree trunks, wooden fences,flowerpots, and buildings.

MATERIALS

• eyedropper

• microscope

• microscope slide and coverslip

• Protococcus (or other algae)

• water

SAFETY INFORMATION

PROCEDURE

1. Locate some Protococcus. Scrape a small sample into a container. Bring thesample to the classroom, and make a wet mount of it as directed by yourteacher. If you can’t find Protococcus outdoors, look for algae on the glass inan aquarium. Such algae may not be Protococcus, but it will be a very goodsubstitute.

2. Set the microscope on low power to examine the algae. On a separate sheetof paper, draw the cells that you see.

3. Switch to high power to examine a single cell. Draw the cell.

4. You will probably notice that each cell contains several chloroplasts. Label achloroplast on your drawing. What is the function of the chloroplast?

5. Another structure that should be clearly visible in all the algae cells is thenucleus. Find the nucleus in one of your cells, and label it on your drawing.What is the function of the nucleus?

6. What does the cytoplasm look like? Describe any movement you see insidethe cells.

Name Class Date


The nucleus of a cell controls most of the activities that take place in that

cell and contains the hereditary information.

The cytoplasm is a clear gel-like substance that fills the cell and surrounds

the organelles. The organelles are floating around in the cytoplasm.

Chloroplasts are the parts of the cell that are responsible for

photosynthesis.



ANALYZE THE RESULTS

1. Are Protococcus single-celled organisms or multicellular organisms?

2. How are Protococcus different from amoebas?

ANSWER KEY



Name Class Date

Cells Alive! continued

Many answers are possible, but the following are most likely: Protococcus

cannot move about as amoebas can; unlike amoebas, they are green and

photosynthesize.

Protococcus is a genus composed of single-celled algae.






MATERIALSThe materials listed on the student page are enough for one group of 5–6 stu-dents. You may wish to have your students use a calculator to complete thisactivity.

PREPARATION NOTESSome students may consider their height and weight to be personal and won’twant to weigh and measure themselves with the others in the class. Give thesestudents the option of using the data of a fictional person, such as one of thefollowing:

Jenny 80 lb 4 ft age 11Ben 65 lb 3 ft age 12Carlos 110 lb 5 ft 2 in. age 11Alexa 120 lb 4 ft 6 in. age 12Tasheika 90 lb 4 ft 6 in. age 13

LAB NOTESSome students will think that their basal metabolic rate, or BMR, is impossiblylow. Emphasize that the BMR is the number of Calories a body needs just to keepthe heart beating, the lungs breathing, and the cells respiring. The BMR is not thenumber of Calories a person needs for an active lifestyle. Of course, a person canconsume fewer than that number of Calories for a day, or even for a few days,without dying. Explain that the Calories required to live during starvation condi-tions are obtained from stored fat. When there is no more fat, then the energycomes from muscle tissue. Under extreme conditions of starvation, the body evenbegins to shut down some organ functions that use energy but that are notrequired for survival, such as the uterine cycle in women. Some students may askwhy the BMR numbers are so much higher in males than in females. Explain thatbefore puberty, the numbers are much closer together. But as boys approachpuberty, they generally develop a higher muscle-to-fat ratio than girls do. Cellularrespiration for muscle tissue requires more energy than for fat tissue.


ANSWER KEY



Kathy LaRoeEast Valley Middle School

East Helena, Montana

1 2 3 4Easy Hard


Holt Science and Technology 71 The Cell in ActionCopyright © by Holt, Rinehart and Winston. All rights reserved.


ANSWER KEY

Every second of your life, your body’s trillions of cells take in, use, and storeenergy. They repair themselves, reproduce, and get rid of waste. Together, theseprocesses are called metabolism. Your cells use the food that you eat to providethe energy you need to stay alive.

Your Basal Metabolic Rate (BMR) is a measurement of the energy that yourbody needs to carry out all the basic life processes while you are at rest. Theseprocesses include breathing, keeping your heart beating, and keeping your body’stemperature stable. Your BMR is influenced by your gender, your age, and manyother things. Your BMR may be different from everyone else’s, but it is normal foryou. In this activity, you will find the amount of energy, measured in Calories, youneed every day in order to stay alive

MATERIALS

• bathroom scale

• tape measure

PROCEDURE

1. Find your weight on a bathroom scale. If the scale measures in pounds, youmust convert your weight in pounds to your mass in kilograms. To convertyour weight in pounds (lb) to mass in kilograms (kg), multiply the number ofpounds by 0.454.

Example: If Carlos 125 lbweighs 125 lb, his � 0.454mass in kilograms is: 56.75 kg

2. Use a tape measure to find your height. If the tape measures in inches, con-vert your height in inches to height in centimeters. To convert your height ininches (in.) to your height in centimeters (cm), multiply the number of inchesby 2.54

If Carlos is 62 in. 62 in. tall, his height in � 2.54centimeters is: 157.48 cm

3. Now that you know your height and mass, use the appropriate formula belowto get a close estimate of your BMR. Your answer will give you an estimate ofthe number of Calories your body needs each day just to stay alive.

Name Class Date




4. Your metabolism is also influenced by how active you are. Talking, walking,and playing games all take more energy than being at rest. To get an idea ofhow many Calories your body needs each day to stay healthy, select thelifestyle that best describes yours from the table below. Then multiply yourBMR by the activity factor.

ANALYZE THE RESULTS

1. In what way could you compare your whole body to a single cell? Explain.

2. Does an increase in activity increase your BMR? Does an increase in activityincrease your need for Calories? Explain your answers.

ANSWER KEY



Name Class Date


Females

65�(10 � your mass in kilograms)

�(1.8 � your height in centimeters)


Males

66� (13.5 � your mass in kilograms)

� (5 � your height in centimeters)


ACTIVITY FACTORS

ActivityActivity lifestyle factor

Moderately inactive(normal, everyday activities) 1.3

Moderately active(exercise 3 to 4 times a week) 1.4

Very active (exercise 4 to 6 times a week) 1.6

Extremely active(exercise 6 to 7 times a week) 1.8

Sample answer: Just as each cell needs energy on a small scale, your body

requires energy on a much larger scale.

Sample answer: Technically, the BMR does not change with activity. The BMR

is the minimum amount of energy a person needs to stay alive. Activity

requires that more energy be added to the BMR, thereby increasing the need

for Calories.

CALCULATING YOUR BMR



DRAW CONCLUSIONS

3. If you are moderately inactive, how many more Calories would you need ifyou began to exercise every day?

APPLYING YOUR DATA

The best energy sources are those that supply the correct amount of Calories foryour lifestyle and also provide the nutrients you need. Research in the library oron the Internet to find out which kinds of foods are the best energy sources foryou. How does your list of best energy sources compare with your diet?

List everything you eat and drink in 1 day. Find out how many Calories are ineach item, and find the total number of Calories you have consumed. How doesthis number of Calories compare with the number of Calories you need each dayfor all your activities?

ANSWER KEY



Name Class Date


Students should multiply their own BMR by 1.3 and then multiply their BMR

by 1.8. Students should subtract the smaller number from the larger number.

This number represents the additional Calories per day the student would

expend shifting from a moderately inactive state to an extremely active one.




Two 45-minute class periods, separated by several days sostudents have time to complete their surveys


LAB NOTES

Family histories will vary. Encourage students to include at least three generations in their histories.

Survey results will vary. Make sure that students actually surveyed each familymember who was available. Responses will vary. You may check family memberswith shaded symbols against the survey results for accuracy.

Percentages will vary. A family member may receive a recessive allele from thefather and a recessive allele from the mother. In such a case, this family memberwill exhibit the recessive form of the trait rather than the dominant form.Because so many children are adopted or live in foster homes or group homes,please emphasize to your students that they may choose any family to study.


ANSWER KEY



Kerry JohnsonIsbell Middle School

Santa Paula, California

1 2 3 4Easy Hard


Holt Science and Technology 70 HeredityCopyright © by Holt, Rinehart and Winston. All rights reserved.


ANSWER KEY

Have you ever wondered about the traits you inherited from your parents? Doyou have a trait that neither of your parents has? In this project, you will developa family tree, or pedigree, similar to the one shown in the diagram below. You willtrace an inherited trait through a family to determine how it has passed from generation to generation.

PROCEDURE

1. The diagram at rightshows a family history.On a separate piece ofpaper, draw a similardiagram of the familyyou have chosen.Include as many familymembers as possible,such as grandparents,parents, children, andgrandchildren. Usecircles to representfemales and squares torepresent males. Youmay include otherinformation, such as thefamily member’s name,birth date, or picture.

2. Use table below to record data about your family. Survey each of the familymembers shown in your family tree. Ask them if they have hair on the middlesegment of their fingers. Write each person’s name in the appropriate square.Explain to each person that it is normal to have either trait. The presence ofhair on the middle segment is the dominant form of this trait.

Name Class Date


Pedigree

Tom1

Jane2

Fran1

Harry2

Mary3

Bob4

Luke1

Mary2

Dylan3

Rosa4

Nathan1

Alicia2

Tara3

IGrandparents

IIParents

IIIChildren

IVGrandchildren

Family members with Family members withDominant trait Recessive trait the dominant trait the recessive trait

Hair present on the Hair absent on themiddle segment of middle segment offingers (H) fingers (h)



3. Trace this trait throughout the family tree you diagrammed in step 1. Shade orcolor the symbols of the family members who demonstrate the dominant formof this trait.

ANALYZE THE RESULTS

1. What percentage of the family members demonstrate the dominant form ofthe trait? Calculate this by counting the number of people who have thedominant trait and dividing this number by the total number of people yousurveyed. Multiply your answer by 100. An example has been done below.

Example: Calculating percentage

10 people with trait � 120 people surveyed 2

1 � 0.50 � 100 � 50% 2

2. What percentage of the family members demonstrate the recessive form ofthe trait? Why doesn’t every family member have the dominant form of thetrait?

3. Choose one of the family members who demonstrates the recessive form ofthe chosen trait. What is this person’s genotype? What are the possible genotypes for the parents of this individual? Does this person have any brothers or sisters? Do they show the dominant or recessive trait?

ANSWER KEY



Name Class Date


Answers may vary.

Answers may vary.

The genotype of the recessive form of the characteristic must be hh

(homozygous recessive). Each allele came from one of the individual’s

parents. Possible genotypes for the parents of the individual expressing the

recessive form are Hh and hh. Does the student know whether either of the

parents expresses the recessive form of the trait? Does the student know if

the individual chosen has brothers or sisters? Are their genotypes known? If

so, have the student decide if each of them has a dominant or recessive

genotype. If a dominant genotype is found among the siblings and one of the

parents is known to have the recessive form, ask the student what the

genotype of the other parent must be (Hh).



DRAW CONCLUSIONS

4. In the space below, draw a Punnett squarelike the one at right. Use this to determinethe genotypes of the parents of the personyou chose in step 3. Write this person’sgenotype in the bottom right-hand corner of your Punnett square. Hint: There may be more than one possible genotype for the parents. Don’t forget to consider the genotypes of the person’s brothers and sisters.

ANSWER KEY



Name Class Date


The Punnett square should show hh in the bottom right-hand corner. One of

the parents must have the genotype hh. The other parent must have either

hh or Hh. If any sibling has the dominant trait, the genotype of the other

parent must be Hh.

? ?

?

?

Father

Mother



Teacher NotesTIME REQUIRED


LAB RATINGTeacher Prep–1Student Set-Up–1Concept Level–2Clean Up–1

LAB NOTES

It is useful to use coin tosses to explain half-life because approximately half thecoins will land heads and half will land tails. Therefore, about half the entirequantity of coins tossed will be eliminated with each successive toss.


ANSWER KEY



1 2 3 4Easy Hard

Karma Houston-HughesKyrene Middle School

Tempe, Arizona

ANSWER KEY


Holt Science and Technology 66 The History of Life on EarthCopyright © by Holt, Rinehart and Winston. All rights reserved.


ANSWER KEY

Carbon-14 is a special unstable element used in the absolute dating of materialthat was once alive, such as fossil bones. Every 5,730 years, half of the carbon-14in a fossil specimen decays or breaks down into a more stable element. In the fol-lowing experiment you will see how pennies can show the same kind of “decay.”

MATERIALS

• container with a cover, large

• pennies (100)

PROCEDURE

1. Place 100 pennies in a large, covered container. Shake the container severaltimes, and remove the cover. Carefully empty the container on a flat surfacemaking sure the pennies don’t roll away.

2. Remove all the coins that have the “head” side of the coin turned upward.Record the number of pennies removed and the number of pennies remainingin the data table below.

3. Repeat the process until no pennies are left in the container. Remember toremove only the coins showing “heads.”

Name Class Date


Number NumberShake of coins of coins

number remaining removed

1

2

3

4

5

6

7

8

9

The graphs should be very similar in shape. With each half-life and each

shake, the number remaining will be reduced by half.



ANSWER KEY



4. On the graph below, label the x-axis “Number of shakes,” and label the y-axis“Pennies remaining.” Using data from your data table, plot the number ofcoins remaining at each shake on your graph. Add squares for number ofshakes, if necessary.

ANALYZE THE RESULTS

1. Examine the Half-life of Carbon-14 graph above. Compare the graph you havemade for pennies with the one for carbon-14. Explain any similarities that you see.



Name Class Date


0 1 2 3 4 5

6.2512.5

25

50

100

Half-life of Pennies100

75

50

25

0 1 2 3 4 5

Half-life of Carbon = 14

Grams ofcarbon=14

Number of half-lives (5,730)





2. Recall that the probability of landing “heads” in a coin toss is 1/2. Use thisinformation to explain why the remaining number of pennies is reduced byabout half each time they are shaken and tossed.

ANSWER KEY



Name Class Date


The remaining number of pennies is reduced by about half each time the

pennies are shaken and tossed because there are only two faces on each

coin. The rules of probability suggest that half will land heads and half will

land tails, and therefore the amount will be reduced by about half with each

shake.



Teacher Notes

TIME REQUIRED



PREPARATION NOTES

Some students will find it easier to make the charts on graph paper, so you maywish to supply graph paper to students.

LAB NOTES

Students should know that travel outside the solar system is not yet possible.This activity should help students categorize organisms or objects by noticingsubtle differences. This activity is a good way to begin a study of classification ofanimals, rocks, or plants. This lab may be useful before introducing dichotomouskeys, for example.


ANSWER KEY



Georgiann DelgadilloEast Valley School DistrictContinuous Curriculum

SchoolSpokane, Washington

1 2 3 4Easy Hard


Holt Science and Technology 61 ClassificationCopyright © by Holt, Rinehart and Winston. All rights reserved.


ANSWER KEY

You are a crew member on the USS Adventure. TheAdventure has been on a 5-year mission to collectlife-forms from outside the solar system. On the voyage back to Earth, your ship went through ameteor shower, which ruined several of thecompartments containing the extraterrestrial life-forms. Now it is necessary to put more than onelife-form in the same compartment.

You have only three undamagedcompartments in your starship. You and your crewmates must stay in one compartment, and thatcompartment should be used for extraterrestrial life-forms only if absolutely necessary. You and yourcrewmates must decide which of the life-forms couldbe placed together. It is thought that similar life-formswill have similar needs. You can use only observablecharacteristics to group the life-forms.

PROCEDURE

1. Use the data table below to make observations about the charac-teristics of the various life-forms pictured on this page.Look at the images in yourtextbook to observe color.

LIFE-FORM CHARACTERISTICS

Name Class Date


Color Shape Legs Eyes

Life-form 1

Life-form 2

Life-form 3

Life-form 4

Life-form 5

Life-form 6

Life-form 7

Life-form 1

Life-form 2

Life-form 3

Life-form 4

Life-form 5

Life-form 7

Life-form 6



2. Describe each characteristic as completely as you can. Based on your obser-vations, determine which of the life-forms are most alike.

3. Look at the data table below. Fill in the table according to the decisions youmade in step 2. State your reasons for the way you have grouped your life-forms.

Life-form Room AssignmentCompartment Life-forms Reasons

1

2

3

4. The USS Adventure has to make one more stop before returning home.On planet X437 you discover the most interesting life-form ever foundoutside of Earth—the CC9, shown at right. Make adecision, based on your previous grouping oflife-forms, about whether you can safely includeCC9 in one of the compartments for the trip to Earth.

ANALYZE THE RESULTS

1. Describe the life-forms in compartment 1. How are they similar? How are theydifferent?

2. Describe the life-forms in compartment 2. How are they similar? How do theydiffer from the life-forms in compartment 1?

ANSWER KEY



Name Class Date




3. Are there any life-forms in compartment 3? If so, describe their similarities. Inwhich compartment will you and your crewmates remain for the journey home?

DRAW CONCLUSIONS

4. Are you able to transport life-form CC9 safely back to Earth? If so, in whichcompartment will it be placed? How did you decide?

APPLYING YOUR DATA

In 1831, Charles Darwin sailed from England on a ship called the HMS Beagle.You have studied the finches that Darwin observed on the Galápagos Islands.What were some of the other unusual organisms he found there? For example,find out about the Galápagos tortoise.

ANSWER KEY



Name Class Date


Answers will depend on how students grouped the life-forms in this lab, and

which characteristics the students used to classify life-form CC9.

The Galápagos tortoise can have a shell length of 1.3 m, a mass of 180 kg, and

live to be 150 years old.

There are no right or wrong answers for this activity. The objective is to allow

students an opportunity to recognize that organisms may be more alike than

they are different. However, you should make sure that students provide good

reasons why they grouped certain life-forms together. There are several ways in

which these seven organisms are similar. For example, four of them are seg-

mented and have no legs. Three of them are geometrically shaped, and three

others have mouths. Have students examine them for less observable character-

istics, such as what kind of body plan or symmetry they have, how they might

obtain food, or whether they might be land dwelling or aquatic.





RATINGTeacher Prep–2Student Set-Up–3Concept Level–4Clean Up–2

MATERIALS

Enlarge the template below to provide students with patterns.

SAFETY INFORMATION

Remind students to review all safety cautions and icons before beginning this labactivity.


ANSWER KEY



Gladys CherniakSt. Paul’s Episcopal School

Mobile, Alabama1 2 3 4Easy Hard

e a a b b c c d d e

f g g h h i i j j f


Holt Science and Technology 66 Bacteria and VirusesCopyright © by Holt, Rinehart and Winston. All rights reserved.


ANSWER KEY

Although viruses are made of only protein and nucleic acids, their structures havemany different shapes that help them attach to and invade living cells. One viralshape can be constructed from the template provided by your teacher. In thisactivity, you will construct and modify a model of a virus.

MATERIALS

SAFETY INFORMATION

PROCEDURE

1. Obtain a virus model template from your teacher. Carefullycopy the template on a piece of construction paper. You maymake the virus model as large as your teacher allows.

2. Plan how you will modify your virus. For example, youmight want to add the tail and tail fibers of a bacteriophageor wrap the model in plastic to represent the envelope thatsurrounds the protein coat in HIV.

3. Color your virus model, and cut it out by cutting on thesolid black lines. Then, fold the virus model along thedotted lines.

4. Glue or tape each lettered tab under the correspondinglettered triangle. For example, glue or tape the large Ztab under the Z-shaded triangle. When you are fin-ished, you should have a closed box with 20 sides.

5. Apply the modifications that you planned. Give your virus a name, and write iton the model. Decorate your classroom with your virus and those of yourclassmates.

ANALYZE THE RESULTS

1. Describe the modifications you made to your virus model, and explain howthe virus might use them.

Name Class Date


• glue (or tape)


• paper, construction

• pipe cleaners, twist ties, buttons, string,plastic wrap, and other scrap materialsfor making variations of the virus

• scissors

• virus model template

Answers may vary.



2. If your virus causes disease, explain what disease it causes, how itreproduces, and how the virus is spread.


Research in the library or on the Internet an unusual virus that causes an illness,such as the influenza virus, HIV, or Ebola virus. Write a paragraph explainingwhat is unusual about the virus, what illness it causes, and how it might beavoided.

ANSWER KEY



Name Class Date

Viral Decorations continued

Answers may vary.

Influenza virus, of course, causes the flu. HIV is the virus that causes AIDS,

and Ebola virus is a rare filovirus that causes a deadly hemorrhagic fever.






MATERIALS

Have students bring materials from home, such as buttons, fringe, pipe cleaners,cotton balls, or anything else that can be used to make a model of a protist.

SAFETY CAUTION



ANSWER KEY



Elizabeth J. RustadScience Department

ChairCoronado Elementary

Gilbert, Arizona1 2 3 4Easy Hard


Holt Science and Technology 72 Protists and FungiCopyright © by Holt, Rinehart and Winston. All rights reserved.


ANSWER KEY

You have studied many of the diverse species of organisms within the kingdomProtista. This may be the first time you have ever seen many of these single-celled eukaryotes. In this activity, you will have an opportunity to express a bit ofcreativity by using what you have learned about these interesting organisms.

MATERIALS

• clothes hanger, wire


• paper (heavyweight construction paper or poster board)

• recycled material of your choice

• scissors

• string, yarn, lightweight wire, or fishing line

• tape, transparent (or glue)

SAFETY INFORMATION

PROCEDURE

1. Research the different kinds of protists you have studied. You may cut outpictures of them from magazines, or you may find examples of protists on theInternet. You may want to investigate Plasmodium, Euglena, amoebas, slimemolds, Radiolaria, Paramecium, Foraminifera, various other protozoans, oreven algae.

2. Using the paper and recycled materials, make a model of each protist youwant to include on your mobile. Be sure to include the special features ofeach protist, such as vacuoles, pseudopods, shells, cilia, or flagella.

3. Use tape or glue to attach special features to give your protists a three-dimensional look.

4. Provide labels for your protist models. For each protist, provide its name,classification, method of movement (if any), method for obtaining food, andany other interesting facts you have learned about it.

5. Attach your protist models to the wire hanger with wire or string. Use tape orglue to attach your labels to each model.

Name Class Date




ANALYZE THE RESULTS

1. What have you learned about the diversity of protists? Include at least threehabitats where protists may be found.


Choose a disease-causing protist. Write a report describing the disease, its effecton people or the environment, and the efforts being made to control it.

ANSWER KEY



Name Class Date

Making a Protist Mobile continued

Sample answer: The kingdom Protista has the greatest diversity of all the

eukaryotes with over 65,000 known species. They can live in many different

environments. They can drift in the ocean, creep across vegetation in fresh-

water rivers and ponds, flourish in deep soil, and even reproduce in the

bodies of other organisms.

Students may choose from any number of disease-causing protists, from

amoeba (amoebic dysentery) to Plasmodium (malaria). Students’ reports

should include some of the symptoms of the disease, how prevalent it is,

and how or if it is controlled.






MATERIALS

The materials listed on the student page are enough for a group of 4–5 students.Collect plant specimens ahead of time or have students bring in five specimensthat they have collected. Students will need to see the leaves as they appear onthe stems, so include as much of the plant as possible.

SAFETY CAUTION


LAB NOTE

This exchange activity can be an effective assessment tool for this lab. Studentswill enjoy challenging their classmates and this is a good way for students tolearn from each other.

LAB NOTES

This activity is designed to help students recognize that leaves have many formsand that the variations of leaf shapes are adaptations for a particular function.This exercise also acquaints students with the identification process used insome field or classification guides. Encourage students to recognize the difference between a stem and a petiole and the difference between a leaf and aleaflet.


ANSWER KEY



Jane LemonsWestern Rockingham

Middle SchoolMadison, North Carolina1 2 3 4Easy Hard


Holt Science and Technology 86 Introduction to PlantsCopyright © by Holt, Rinehart and Winston. All rights reserved.


ANSWER KEY

Imagine you are a naturalist all alone on an expedition in a rain forest. You havefound several plants that you think have never been seen before. You must con-tact a botanist, a scientist who studies plants, to confirm your suspicion. Becausethere is no mail service in the rain forest, you must describe these species com-pletely and accurately by radio. The botanist must be able to draw the leaves ofthe plants from your description. In this activity, you will carefully describe fiveplant specimens by using the examples and vocabulary lists in this lab.

MATERIALS

• gloves, protective • plant guidebook (optional)

• leaf specimens (5)

SAFETY INFORMATION

PROCEDURE

1. Examine the leaf characteristics illustrated on the pages for this lab in yourtextbook. You will notice that more than one term is needed to completelydescribe a leaf. The first leaf shown in the textbook has been labeled for youusing the examples and vocabulary lists found in this lab.

2. On a sheet of paper, draw a diagram of a leaf from each plant specimen.

3. Next to each drawing, carefully describe the leaf. Include general characteris-tics, such as relative size and color. For each plant, identify the following: leafshape, stem type, leaf arrangement, leaf edge, vein arrangement, and leaf-baseshape. Use the terms and vocabulary lists provided to describe each leaf asaccurately as possible and to label your drawings.

ANALYZE THE RESULTS

1. What is the difference between a simple leaf and a compound leaf?

2. Describe two different vein arrangements in leaves.

Name Class Date


Answers should indicate that veins can be arranged in one of three ways:

parallel, extending straight up and down the leaf (which is usually elon-

gated); pinnate, which on a single leaf is a network of veins extending out

from a central vein; or palmate, which is an arrangement of veins originating

from a single point on a leaf that has several lobes.

A simple leaf is a single leaf at the end of a single petiole. A compound leaf

has several leaflets on the end of a petiole in various arrangements.



3. Based on what you know about adaptation, explain why there are so manydifferent leaf variations.


Choose a partner. Using the keys and vocabulary in this lab, describe a leaf, andsee if your partner can draw the leaf from your description. Switch roles, and seeif you can draw a leaf from your partner’s description.

ANSWER KEY



Name Class Date

Leaf Me Alone! continued

Answers may vary but should include adaptations for water conservation,

light reception, and insect resistance. Leaves vary because they serve many

functions. Explain that leaf shape is only one of the adaptations leaves can

have and that the thickness of the leaf and the waxy coating of the leaf are

also adaptations. Have students compare an oak leaf with a conifer leaf.

LEAF SHAPES VOCABULARY LIST

cordate—heart shaped

lanceolate—sword shaped

lobate—lobed

oblong—rounded at the tip

orbicular—disk shaped

ovate—oval shaped, widest at base ofleaf

peltate—shield shaped

reniform—kidney shaped

sagittate—arrow shaped

STEMS VOCABULARY LIST

herbaceous—green, nonwoody stems

woody—bark or barklike covering onstem

LEAF ARRANGEMENTS VOCABULARY LIST

alternate—alternating leaves orleaflets along stem or petiole

compound—leaf divided into seg-ments, or several leaflets on a petiole

opposite—compound leaf with severalleaflets arranged oppositely along apetiole

palmate—single leaf with veinsarranged around a center point

palmate compound—several leafletsarranged around a center point

petiole—leaf stalk

pinnate—single leaf with veinsarranged along a center vein

pinnate compound—several leafletson either side of a petiole

simple—single leaf attached to stemby a petiole

This exchange activity can be an effective assessment tool for this lab. Students

will enjoy challenging their classmates, and this is a good way for students to

learn from each other.




One or two 45-minute class periods


MATERIALS

The materials listed on the student page are enough for 1 student. The plant usedin this lab can be any leafy plant, such as a bean plant or a coleus. The plantshown is a coleus with all but the top four leaves trimmed away.

SAFETY CAUTION


LAB NOTES

If your lab period is short, you may want to eliminate the measurement of theheight of water in the test tube at 40 min.

Although it is not essential to the activity, you may want to begin with an exactamount of water in each test tube. Students would then know that the differencecan be due only to evaporation and transpiration.


ANSWER KEY



David SparksRedwater Junior High School

Redwater, Texas1 2 3 4Easy Hard


Holt Science and Technology 62 Plant ProcessesCopyright © by Holt, Rinehart and Winston. All rights reserved.


ANSWER KEY

You are trying to find a way to drain an area that is flooded with water pollutedwith fertilizer. You know that a plant releases water through the stomata in itsleaves. As water evaporates from the leaves, more water is pulled up from theroots through the stem and into the leaves. By this process, called transpiration,

water and nutrients are pulled into the plant from the soil. About 90% of thewater a plant takes up through its roots is released into the atmosphere as watervapor through transpiration. Your idea is to add plants to the flooded area thatwill transpire the water and take up the fertilizer in their roots.

How much water can a plant take up and release in a certain period of time?In this activity, you will observe transpiration and determine one stem’s rate oftranspiration.

MATERIALS

SAFETY INFORMATION

PROCEDURE

1. Use the data table below for recording your measurements.

Height of Water in Test Tubes

2. Fill each test tube approximately three-fourths full of water. Place both testtubes in a test-tube rack.

3. Place the plant stem so that it stands upright in one of the test tubes.

Name Class Date


• clock

• coleus or other plant stem cutting

• glass-marking pen

• metric ruler

• paper, graph

• test tube (2)

• test-tube rack

• water

Test tube Test tubeTime with plant without plant

Initial

After 10 min

After 20 min

After 30 min

After 40 min

Overnight



4. Use the glass-marking pen to mark the water level in each of the test tubes.Be sure you have the plant stem in place in its test tube before you mark thewater level. Why is this necessary?

5. Measure the height of the water in each test tube. Be sure to hold the testtube level, and measure from the waterline to the bottom of the curve at thebottom of the test tube. Record these measurements on the row labeled“Initial.”

6. Wait 10 min, and measure the height of the water in each test tube again.Record these measurements in your data table.

7. Repeat step 6 three more times. Record your measurements each time.

8. Wait 24 hours, and measure the height of the water in each test tube. Recordthese measurements in your data table.

9. Use the graph tothe right to plotthe data fromyour data table.Draw a line foreach test tube.Use a differentcolor for eachline.

10. Calculate the rateof transpirationfor your plant byusing the follow-ing operations:

ANSWER KEY



Name Class Date


0 10 20 30 40

102030405060708090100

Time (min)

Hei

ght

of w

ater

in

test

tub

e (m

m)

Test tube with plant:


Difference in height of water (A)

Test tube without plant:


Difference in height of water (B)

Water height differencedue to transpiration:

Difference A– Difference B

Water lost due totranspiration (in millimeters) in 24 hours

Rate of Transpiration

red—test tube without plantblue—test tube with plant



ANALYZE THE RESULTS

1. What was the purpose of the test tube that held only water?

2. What caused the water to go down in the test tube containing the plant stem?Did the same thing happen in the test tube with water only? Explain youranswer.

3. What was the calculated rate of transpiration per day?

4. Using your graph, compare the rate of transpiration with the rate ofevaporation alone.

5. Prepare a presentation of your experiment for your class. Use your datatables, graphs, and calculations as visual aids.

APPLYING YOUR DATA

How many leaves did your plant sprigs have? Use this number to estimate whatthe rate of transpiration might be for a plant with 200 leaves. When you have youranswer in millimeters of height in a test tube, pour this amount into a graduatedcylinder to measure it in milliliters.

ANSWER KEY



Name Class Date


Sample answer: Water in the test tube containing the plant stem will be lost

through evaporation and transpiration. Evaporation is the only means of

water loss in the test tube without the plant stem.

Answers may vary according to several variables in the classroom, such as

the amount of light and the temperature.

Answers may vary. Have students compare and contrast the lines on the

graph and explain how the graph is easier to interpret than numbers in a

data list.

Sample answer: The test tube that held only water was a control; it would

lose water only by evaporation.

Answers may vary.






MATERIALS

The materials listed on the student page are enough for a group of 4–5 students.

SAFETY CAUTION

Remind students to review all safety cautions and icons before beginning this labactivity. Students may wish to wear protective gloves while handling the worms.


ANSWER KEY



Gladys CherniakSt. Paul’s Episcopal School

Mobile, Alabama1 2 3 4Easy Hard

LAB NOTES

Earthworms are scientifically classified as animals belonging to the orderOligochaeta, class Chaetopoda, and phylum Annelida. There are about 1,800species of earthworms. Only two of these are grown commercially. Earthwormshave setae, or bristles, located on each segment that help them move. Earthworms have both male and female reproductive organs. They usually do not self-fertilize, but they do exchange sperm as they pass in their burrows. Eggs aredeposited in the burrow in a cocoon. The cocoon is manufactured by the clitel-lum that encircles the body of the worm. Different segments of the earthwormperform different functions, just as each of our body parts do. Earthworms havefrom 95 to 150 segments, depending on the species.


Holt Science and Technology 70 Animals and BehaviorCopyright © by Holt, Rinehart and Winston. All rights reserved.


ANSWER KEY

Earthworms have been digging in the Earth for more than 100 million years!Earthworms fertilize the soil with their waste and loosen the soil when they tun-nel through the moist dirt of a garden or lawn. Worms are food for many animals,such as birds, frogs, snakes, rodents, and fish. Some say they are good food forpeople, too!

In this activity, you will observe the behavior of a live earthworm. Rememberthat earthworms are living animals that deserve to be handled gently. Be sure tokeep your earthworm moist during this activity. The skin of the earthworm muststay moist so that the worm can get oxygen. If the earthworm’s skin dries out, theworm will suffocate and die. Use a spray bottle to moisten the earthworm withwater.

MATERIALS

SAFETY INFORMATION

PROCEDURE

1. Place a wet paper towel in the bottom of a dissecting pan. Put a live earth-worm on the paper towel, and observe how the earthworm moves. Recordyour observations.

2. Use the probe to carefully touch the anterior end (head) of the worm. Gentlytouch other areas of the worm’s body with the probe. Record the kinds ofresponses you observe.

3. Place celery leaves at one end of the pan. Record how the earthwormresponds to the presence of food.

4. Shine a flashlight on the anterior end of the earthworm. Record the earth-worm’s reaction to the light.

5. Line the bottom of the shoe box with a damp paper towel. Cover half of theshoe box with the box top.

6. Place the worm on the uncovered side of the shoe box in the light. Recordyour observations of the worm’s behavior for 3 min.

7. Place the worm in the covered side of the box. Record your observations for3 min.

Name Class Date


• celery leaves

• clock

• dissecting pan

• earthworm, live

• flashlight

• paper towels

• probe

• ruler, metric

• shoe box, with lid

• soil

• spray bottle

• water



8. Repeat steps 6–7 three times.

9. Spread some loose soil evenly in the bottom of the shoe box so that the soil isabout 4 cm deep. Place the earthworm on top of the soil. Observe and recordthe earthworm’s behavior for 3 min.

10. Dampen the soil on one side of the box, and leave the other side dry. Placethe earthworm in the center of the box between the wet and dry soil. Coverthe box, and wait 3 min. Uncover the box, and record your observations.Repeat this procedure three times. (You may need to search for the worm!)

ANALYZE THE RESULTS

1. How did the earthworm respond to being touched? Were some areas moresensitive than others?

2. How did the earthworm respond to the presence of food?

DRAW CONCLUSIONS

3. How is the earthworm’s behavior influenced by light? Based on your observations, describe how an animal’s response to a stimulus might provideprotection for the animal.

4. When the worm was given a choice of wet or dry soil, which did it choose?Explain this result.

ANSWER KEY



Name Class Date


Students’ answers may vary according to their own observations. They will

probably observe that the worm squirms when touched and that some areas

Students’ answers may vary according to their own observations. They will

probably observe that the worm squirms when touched and that some areas

are more sensitive than others, such as the clitellum.

Responses to food may vary.

are more sensitive than others, such as the clitellum.

Responses to food may vary.

Students will probably observe that earthworms avoid light and prefer moist

soil. Students may describe the worm’s behavior as self-protective.

Students will probably observe that earthworms avoid light and prefer moist

soil. Students may describe the worm’s behavior as self-protective.




Based on your observations of an earthworm’s behavior, prepare a poster showing where you might expect to find earthworms. Draw a picture with col-ored markers, or cut out pictures from magazines. Include all the variables thatyou used in your experiment, such as soil or no soil, wet or dry soil, light or dark,and food. Write a caption at the bottom of your poster describing where earth-worms might be found in nature.

ANSWER KEY



Name Class Date


Students’ posters should describe warm, moist soil; darkness; and partially

decayed organic matter for food.




One to two 45-minute class periods

RATINGTeacher Prep–3Student Set-Up–2Concept Level–2Clean Up–2

MATERIALS

The materials listed on the student page are enough for one student or a smallgroup of students. Instead of 600 mL beakers, you may use the bottom halves oftwo clear plastic 2 L bottles. You will need to prepare these ahead of time. Thecut on the bottle should be as even as possible to facilitate taping the open endstogether in step 5.

SAFETY CAUTION


LAB NOTES

Explain to students that they must move slowly so they won’t startle the cricketand alter its behavior. The apple must be removed in step 5 before the containersare taped together. The apple would be an unwanted variable in the tests thatfollow.

If you decide to extend this activity over two class periods, the cricket will befine overnight in a covered 500 mL beaker. The cricket will need a slice of potatoor apple for food and moisture.


ANSWER KEY



Alonda DroegePioneer Middle SchoolSteilacom, Washington

1 2 3 4Easy Hard


Holt Science and Technology 76 InvertebratesCopyright © by Holt, Rinehart and Winston. All rights reserved.


ANSWER KEY

Insects are a special class of invertebrates with more than 750,000 knownspecies. Insects may be the most successful group of animals on Earth. In thisactivity you will observe a cricket’s structure and the simple adaptive behaviorsthat help make it so successful. Remember, you will be handling a living animalthat deserves to be treated with care.

MATERIALS

SAFETY INFORMATION

PROCEDURE

1. Place a cricket in a clean 600 mL beaker, and quickly cover the beaker withplastic wrap. The supply of oxygen in the container is enough for the cricketto breathe while you complete your work.

2. While the cricket is getting used to the container, look at the data table below.

CRICKET BODY STRUCTURES

3. Without making much movement, begin to examine the cricket. Fill in yourdata table with your observations of the cricket’s structure.

4. Place a small piece of apple in the beaker. Set the beaker on a table. Sitquietly for several minutes and observe the cricket. Any movement may causethe cricket to stop what it is doing. Record your observations.

5. Remove the plastic wrap from the beaker, remove the apple, and quicklyattach a second beaker. Join the two beakers together at the mouths withmasking tape. Handle the beakers carefully. Remember, there is a livinganimal inside.

Name Class Date


• aluminum foil

• apple

• bags, plastic, sealable (2)

• beaker, 600 mL (2)

• cricket (2)

• hand lens (optional)

• ice, crushed

• lamp

• plastic wrap

• tape, masking

• water, tap, hot

Number Description

Body segments

Antennae

Eyes

Wings



6. Wrap one of the joined beakers with aluminum foil.

7. If the cricket is hiding under the aluminum foil, gently tap the sides of thebeaker until the cricket is exposed. Lay the joined beakers on their sides, andshine a lamp on the uncovered side. Record the cricket’s location.

8. Record the cricket’s location after 5 min. Without disturbing the cricket,carefully move the aluminum foil to the other beaker. After 5 min, record thecricket’s location. Repeat this process one more time to see if you get thesame result.

9. Fill a sealable plastic bag halfway with crushed ice. Fill another bag halfwaywith hot tap water. Seal each bag, and arrange them side by side on the table.

10. Remove the aluminum foil from the beakers. Gently rock the joined beakersfrom side to side until the cricket is in the center. Place the beakers on theplastic bags, as shown in the LabBook in the textbook.

11. Observe the cricket’s behavior for 5 min. Record your observations.

12. Set the beakers on one end for several minutes to allow them to return toroom temperature. Repeat steps 10–12 three times. (Why do you think it isnecessary to allow the beakers to return to room temperature each time?)

13. Set the beakers on one end. Carefully remove the masking tape, and separatethe beakers. Quickly replace the plastic wrap over the beaker containing thecricket. Allow your cricket to rest while you read through the two data tableson the following page.

14. Observe the cricket’s movement in the beaker every 15 seconds for 3 min. Fillin the Cricket (alone) data table using the following codes: 0 � no movement,1 � slight movement, and 2 � rapid movement.

15. Obtain a second cricket from your teacher, and place this cricket in thecontainer with the first cricket. Every 15 seconds, record the movement ofeach cricket in the Cricket A and Cricket B data table using the codes given instep 14.

ANALYZE THE RESULTS

1. Describe crickets’ feeding behavior. Are they lappers, suckers, or chewers?

ANSWER KEY



Name Class Date


If the beakers are still warm, experimental conditions will not be the same

for each trial.

All answers will depend on the students’ observations. The following

answers are the expected observations: Crickets are chewers.



CRICKET (alone) CRICKET A AND CRICKET B

2. Do crickets prefer light or darkness? Explain.

3. From your observations, what can you infer about a cricket’s temperaturepreferences?

DRAW CONCLUSIONS

4. Based on your observations of Cricket A and Cricket B, what generalstatements can you make about the social behavior of crickets?

ANSWER KEY



Name Class Date


15 s

30 s

45 s

60 s

75 s

90 s

105 s

120 s

135 s

150 s

165 s

180 s

A B

15 s

30 s

45 s

60 s

75 s

90 s

105 s

120 s

135 s

150 s

165 s

180 s

Answers may vary, but should reflect that, if well-fed, crickets generally

tolerate each other very well. However, they will fight and even eat each

other if they are not fed properly.

Crickets will prefer the warmer location.

Crickets generally prefer darkness. They will move from light areas into

dark areas.



APPLYING YOUR DATA

Make a third data table titled “Cricket and Another Species of Insect.” Introduceanother insect, such as a grasshopper, into the beaker. Record your observationsfor 3 min. Write a short summary of the cricket’s reaction to another species.

ANSWER KEY



Name Class Date


Explain to the students that both threatening actions and submissive responses

are agonistic behaviors that often result in producing a “winner.” For example,

wolves that snarl and bare their teeth at a competitor for a mate are displaying

agonistic behavior. Ask students to watch this activity carefully. Ask them to be

attentive so that they will observe the first signs of agonistic behavior if any

arise. If the animals show signs that they are going to fight, tell students to

remove one of them from the container immediately.





LAB RATINGSTeacher Prep–3Student Set-Up–1Concept Level–2Clean Up-1

SAFETY CAUTION


You will need to provide protective gloves for the students. Students’ handsmay make the frog vulnerable to infection. Also, frogs are known to carry salmo-nella. Students should wash their hands thoroughly with soap and warm waterafter handling the frog.

PREPARATION NOTES

Frogs collected in the wild are best for this activity because they are easilyreleased. Frogs from pet stores must NOT be released into the wild.

If you can divide the class into groups with several observations going on atthe same time, you can use a smaller container for each frog. Containers can be alarge glass mixing bowl or something similar. Students may bring containers fromhome as well. Tree frogs are common in pet stores. They are fun to observe, especially if you can find some small crickets to feed them so that students canobserve their feeding behavior.

You may substitute another amphibian, such as water doggies, an immaturestage of salamanders. Water doggies are especially interesting if they can be keptin the classroom so students can observe their development into salamanders.

Frogs and water doggies may be obtained in pet stores, in the wild, and in bait shops.

LAB NOTES

Several years ago, some students who were out collecting frogs for an activitysimilar to this lab found severe birth defects and mutations among the frogs theyfound. A good way to introduce this activity may be to find a news clipping fromthis event or information about frog deformities taken from the Internet.


ANSWER KEY



Kerry A. JohnsonIsbell Middle School


1 2 3 4Easy Hard


Holt Science and Technology 65 Fishes, Amphibians, and ReptilesCopyright © by Holt, Rinehart and Winston. All rights reserved.


ANSWER KEY

Imagine that you are a scientist interested in amphibians. You have heard in thenews about amphibians disappearing all over the world. What a great loss it willbe to the environment if all amphibians become extinct! Your job is to learn asmuch as possible about how frogs normally behave so that you can act as aresource for other scientists who are studying the problem. In this activity, youwill observe a normal frog in a dry container and in water.

MATERIALS

SAFETY INFORMATION

PROCEDURE

1. In the following table, note all of your observations of the frog in thisinvestigation.

Name Class Date


• beaker, 600 mL

• container half-filled withdechlorinated water

• crickets, live

• frog, live, in a dry container


• rock, large (optional)

Characteristic Observation

Breathing

Eyes

Legs

Response to food

Skin texture

Swimming behavior

Skin coloration



OBSERVATIONS OF A LIVE FROG

2. Observe a live frog in a dry container. Draw a picture of the frog. Label theeyes, nostrils, front legs, and hind legs.

3. Watch the frog’s movements as it breathes air with its lungs. Write a descrip-tion of the frog’s breathing.

4. Look closely at the frog’s eyes, and note their location. Examine the upperand lower eyelids as well as the transparent third eyelid. Which of these threeeyelids actually moves over the eye?

5. Study the frog’s legs. Note in your data table the difference between the frontand hind legs.

6. Place a live insect, such as a cricket, in the container. Observe and recordhow the frog reacts.

7. Carefully pick up the frog, and examine its skin. How does it feel? Caution:

Remember that a frog is a living thing and deserves to be handled gently andwith respect.

8. Place a 600 mL beaker in the container. Place the frog in the beaker. Coverthe beaker with your hand, and carry it to a container of dechlorinated water.Tilt the beaker and gently submerge it in the water until the frog swims out ofthe beaker.

9. Watch the frog float and swim in the water. How does the frog use its legs toswim? Notice the position of the frog’s head.

10. As the frog swims, bend down and look up into the water so that you can seethe underside of the frog. Then look down on the frog from above. Comparethe color on the top and the underneath sides of the frog. Record your observations in your data table.

ANALYZE THE RESULTS

1. From the position of the frog’s eyes, what can you infer about the frog’s fieldof vision? How might the position of the frog’s eyes benefit the frog while it isswimming?

2. How can a frog “breathe” while it is swimming in water?

ANSWER KEY



Name Class Date




3. How are the hind legs of a frog adapted for life on land and in water?

4. What differences did you notice in coloration on the frog’s top side and itsunderneath side? What advantage might these color differences provide?

5. How does the frog eat? What senses are involved in helping the frog catch itsprey?

APPLYING YOUR DATA

Observe another type of amphibian, such as a salamander. How do theadaptations of other types of amphibians compare with those of the frog youobserved in this investigation?

ANSWER KEY



Name Class Date


1.–5. Have students speculate about the form and function of the frog’s

structure. Discuss the camouflage coloration of a frog. Ask how the

skin of a frog differs from that of a reptile, and note that the two

different forms have two different functions. Discuss the fact that the

frog’s skin must stay wet in order for gas exchange to occur.

Answers may vary, but students should notice several similar adaptations

among amphibians.



Teacher Notes and Answer KeyTIME REQUIREDOne or two 45-minute class periods


MATERIALSThe materials listed on the student page are enough for a group of 4–5 students.Materials for this activity can include recycled materials, glue, buttons, pipecleaners, poster paints and brushes, and any number of other art or craft sup-plies. Have students bring in as much as they can for their own project and toshare.

LAB NOTESThis lab provides an opportunity for students to exercise a great deal of creativityand to expand their understanding of adaptations. Most students will probablyenjoy choosing the adaptations and inventing a niche where those adaptationsare useful. Help them understand that environments and adaptations usuallyevolve together in the natural world, not one before the other. You may want tomake sets of the adaptations and put them in a container and have studentsselect one from the container. This selection process may lessen duplicationin the classroom. Someone might be challenged to design a flying decomposerwith armor!


ANSWER KEY



Alonda DroegePioneer Middle SchoolSteilacom, Washington

1 2 3 4Easy Hard


Holt Science and Technology 69 Interactions of Living ThingsCopyright © by Holt, Rinehart and Winston. All rights reserved.


ANSWER KEY

Since the beginning of life on Earth, species have had special characteristicscalled adaptations that have helped them survive changes in environmental con-ditions. Changes in a species’ environment include climate changes, habitatdestruction, or the extinction of prey. These things can cause a species to die outunless the species has a characteristic that helps it survive. For example, aspecies of bird may have an adaptation for eating sunflower seeds and ants. If theant population dies out, the bird can still eat seeds and can therefore survive. Inthis activity, you will explore several adaptations and design an organism withadaptations you choose. Then, you will describe how these adaptations help theorganism survive.

MATERIALS

SAFETY INFORMATION

PROCEDURE

1. Study the chart below. Choose one adaptation from each column. Forexample, an organism might be a scavenger that burrows undergroundand has spikes on its tail!

Adaptations

Name Class Date


Diet Type of transportation Special adaptation

carnivore flies uses sensors to detect heat

herbivore glides through the air is active only at night and has excellent night vision

omnivore burrows underground changes colors to match its surroundings

scavenger runs fast has armor

decomposer swims has horns

hops can withstand extreme temperature changes

walks secretes a terrible and sickening scent

climbs has poison glands

floats has specialized front teeth

slithers has tail spikes

stores oxygen in its cells so it does not have tobreathe continuously

one of your own invention

• arts-and-crafts materials, various


• magazines for cutouts

• poster board

• scissors



2. Design an organism that has the three adaptations you have chosen. Useposter board, colored markers, picture cutouts, or craft materials of yourchoosing to create your organism.

3. Write a caption on your poster describing your organism. Describe its appear-ance, its habitat, its niche, and the way its adaptations help it survive. Giveyour organism a two-part “scientific” name that is based on its characteristics.

4. Display your creation in your classroom. Share with classmates how youchose the adaptations for your organism.

ANALYZE THE RESULTS

1. What does your imaginary organism eat?

2. In what environment or habitat would your organism be most likely to sur-vive—in the desert, tropical rain forest, plains, icecaps, mountains, or ocean?Explain your answer.

3. Is your creature a mammal, a reptile, an amphibian, a bird, or a fish? Whatmodern organism (on Earth today) or ancient organism (extinct) is yourimaginary organism most like? Explain the similarities between the twoorganisms. Do some research outside the lab, if necessary, to find out about areal organism that may be similar to your imaginary organism.

DRAW CONCLUSIONS

4. If there were a sudden climate change, such as daily downpours of rain in adesert, would your imaginary organism survive? What adaptations for surviv-ing such a change does it have?

ANSWER KEY



Name Class Date


Answers may vary.

1.–3. All answers will depend on the adaptations that the student chose and

the organism the student invented. Students should relate one or more

adaptations to what kinds of food the organism eats, where the animal lives,

or what kind of animal it is.



APPLYING YOUR DATA

Call or write to an agency such as the U.S. Fish and Wildlife Service to get a listof endangered species in your area. Choose an organism on that list.Describe the organism’s niche and any special adaptations it has that help it survive. Find out whyit is endangered and what is being done toprotect it. Examine the illustration of theanimal at right. Based on its physicalcharacteristics, describe its habitat andniche. Is this a real animal?

ANSWER KEY



Name Class Date


This activity is a good way to expand your study of the environment. Students

can relate problems in the area where they live to adaptations. Often, people

wonder why an organism doesn’t just “adapt” to changes in its environment.

This activity is a good opportunity to learn firsthand why adaptation can’t

happen within the span of a single generation and why organisms become endan-

gered. The animal in the illustration is a duck-billed platypus, an actual mam-

mal. The platypus has webbed feet and a flat tail that help it swim through the

water. It also uses claws to dig and a flat, rubbery bill to search the mud for

worms, crayfish, and other food. The duck-billed platypus lives in the rivers and

ponds of Australia.



Teacher Notes and Answer KeyTIME REQUIREDOne 45-minute class and three 5-minute periodicobservation periods


MATERIALS

The materials listed on the student page are enough for the entire class. You maywant to use a large container, such as a 10 gal aquarium, so each student in theclass can contribute a small amount of soil from different areas. Students mightbe able to bring fishbowls from home. If you have enough fishbowls and sunnywindows, students really might enjoy seeing what comes up in their own con-tainer. If you do not have a sunny window, the containers can be placed wherethey will get the most light in the classroom. They need warmth for germinationto occur, and light is necessary after the seedlings emerge from the soil.

SAFETY CAUTION

Check for any known allergies to molds before having students begin this lab.There may be molds in the soil.


ANSWER KEY



Kerry JohnsonIsbell Middle School


1 2 3 4Easy Hard


Holt Science and Technology 52 Cycles in NatureCopyright © by Holt, Rinehart and Winston. All rights reserved.


ANSWER KEY

Succession is the natural process of the introduction and development of livingthings in an area. The area could be one that has never supported life before andhas no soil, such as a recently cooled lava flow from a volcano. In an area wherethere is no soil, the process is called primary succession. In an area where soilalready exists, such as an abandoned field or a forest after a fire, the process iscalled secondary succession. In this investigation, you will build a model of sec-ondary succession using natural soil.

MATERIALS

SAFETY INFORMATION

PROCEDURE

1. Place the natural soil you brought from home or the schoolyard into thefishbowl, and dampen the soil with 250 mL of water. Cover the top of thefishbowl with plastic wrap, and place the fishbowl in a sunny window.Caution: Do not touch your face, eyes, or mouth during this activity. Washyour hands thoroughly when you are finished.

2. For 2 weeks, observe the fishbowl for any new growth. Describe and drawany new organisms you observe. Record these and all other observations.

3. Identify and record the names of as many of these new organisms as you can.

ANALYZE THE RESULTS

1. What kinds of plants sprouted in your model of secondary succession? Werethey tree seedlings, grasses, or weeds?

Name Class Date


• balance


• large fishbowl

• plastic wrap

• protective gloves

• soil from home or schoolyard, 500 g

• water, 250 mL

Plants that sprout should be plants common to the local area. They can be

identified using a local-area field guide as soon as dicot seedlings have

developed true leaves. Monocots will probably look like grasses.



2. Were the plants that sprouted in the fishbowl unusual or common for yourarea?

DRAW CONCLUSIONS

3. Explain how the plants that grew in your model of secondary succession canbe called pioneer species.

APPLYING YOUR DATA

Examine each of the photographs from the pages for this lab in your textbook.Determine whether each area, if abandoned forever, would undergo primary orsecondary succession. You may decide that an area will not undergo successionat all. Explain your reasoning.

ANSWER KEY



Name Class Date

A Passel o’ Pioneers continued

• Eutrophic pond: A eutrophic pond will eventually fill with sediment. At

first, aquatic plants will grow. Later, when the pond is completely filled, the

area will undergo secondary succession.

• Bulldozed land: Left abandoned, this area will undergo secondary succes-

sion just as abandoned farmland will.

• Shipping port parking lot: If the parking lot is abandoned forever, cracks

will appear, exposing the soil underneath, and secondary succession will

proceed. Some areas of this vast parking lot may even undergo primary

succession, where concrete surfaces can be home to lichens.

• Mount St. Helens volcano: The explosion of Mount St. Helens caused an

enormous mudslide and released tons of ash. Areas smothered by ash

underwent primary succession. The entire region is now in various stages

of secondary succession.

Answers may vary. Students should recognize common plants.

All the plants that come up in students’ models of succession are pioneers

because they are the first plants to grow in an area. Ask students if a tree

can be a pioneer. (A tree can be a pioneer if it is one of the first plants to

grow in an area. However, pioneers are usually plants that grow rapidly and

that produce many seeds that are dispersed over a large area.)






MATERIALS

The sponges used in this lab can be either natural sponges or the synthetic spongesavailable in grocery stores. Use 3 in.� 6 in. sponges, 1 per student, cut in half.


ANSWER KEY



James ChinFrank A. Day Middle SchoolNewtonville, Massachusetts

1 2 3 4Easy Hard


Holt Science and Technology 67 The Earth’s EcosystemsCopyright © by Holt, Rinehart and Winston. All rights reserved.


ANSWER KEY

Organisms that live in the desert have some unusual methods for conservingwater. Conserving water is a special challenge for animals that live in the desert.In this activity you will invent a water-conserving “adaptation” for a desert animal, represented by a piece of sponge. You will protect your wet desertsponge so it will dry out as little as possible over a 24 h period.

MATERIALS

ASK A QUESTION

1. How can an animal conserve water in the desert?

FORM A HYPOTHESIS

2. Plan a method for keeping your “desert animal” from drying out. Your “animal” must be in the open for at least 4 h during the 24 h period. Realdesert animals expose themselves to the dry desert heat to search for food.Write your plan and predictions about the outcome of your experiment.

3. Design and draw data tables, if necessary. Have your teacher approve yourplan before you begin.

TEST THE HYPOTHESIS

4. Soak two pieces of sponge in water until they begin to drip. Place each pieceon a balance, and record its mass.

5. Immediately protect one sponge according to your plan. Place both pieces inan area where they will not be disturbed. You should take your protected“animal” out for feeding for a total of at least 4 h.

6. At the end of 24 h, place each piece of sponge on the balance again, andrecord its mass.

Name Class Date


• balance

• sponge, dry, 8 cm � 8 cm � 2 cm (2 pieces)

• water

• other materials as needed




ANALYZE THE RESULTS

1. Describe the adaptation you used to help your “animal” survive. Was it effective? Explain.

2. What was the purpose of leaving one of the sponges unprotected? How didthe water loss in each of your sponges compare?


Conduct a class discussion about other adaptations and results. How can yourelate these invented adaptations to adaptations for desert survival among realorganisms?

ANSWER KEY



Name Class Date

Life in the Desert continued

Students should describe the kind of covering or protection they provided

for their “adapted” sponge. Effectiveness of the adaptation will be measured

by the amount of water lost over 24 h. Students will want their sponges to

dry out as little as possible.

The unprotected sponge represents the organism that has no adaptation for

conserving water. The unprotected sponge should dry out far more than the

protected sponge.




One to two 45-minute class periods


MATERIALSBecause this is mainly an observation activity, few materials are needed. If binoculars or magnifying lenses are available, however, they may be helpful.

LAB NOTESEven if your school has no area where there is sand, dirt, grass, or trees, ask students to observe puddles, the underside of eaves, the area under drain spouts,and the ground under rocks. Students should observe the areas they have chosenat least twice a day.


ANSWER KEY



Barry BishopSan Rafael Junior High

Ferron, Utah1 2 3 4Easy Hard


Holt Science and Technology 69 The Earth’s EcosystemsCopyright © by Holt, Rinehart and Winston. All rights reserved.


ANSWER KEY

In your study of ecosystems, you learned that a biome is a very large ecosystemthat includes a set of smaller, related ecosystems. For example, a coniferous forest biome may include a river ecosystem, a wetland ecosystem, and a lakeecosystem. Each of those ecosystems may include several other smaller, relatedecosystems. Even cities have mini-ecosystems! You may find a mini-ecosystem ona patch of sidewalk, in a puddle of rainwater, under a leaky faucet, in a shadyarea, or under a rock. In this activity, you will design a method for comparing twodifferent mini-ecosystems found near your school.

MATERIALS

• items to be determined by the students and approved by the teacher

SAFETY INFORMATION

ASK A QUESTION

1. Examine the grounds around your school, and select two different areas youwish to investigate. Decide what you want to learn about your mini-ecosystems.For example, you may want to know what kind of living things each areacontains. Be sure to get your teacher’s approval before you begin.

FORM A HYPOTHESIS

2. For each mini-ecosystem, make data tables for recording your observations.

Name Class Date





TEST THE HYPOTHESIS

3. Observe your mini-ecosystem according to your plan at several different timepoints throughout the day. Record your observations.

4. Wait 24 h and observe your mini-ecosystem again at the same times that youobserved it the day before. Record your observations.

5. Wait 1 week, and observe your mini-ecosystem again at the same times.Record your observations.

ANALYZE THE RESULTS

1. What factors determine the differences between your mini-ecosystems? Identifythe factors that set each mini-ecosystem apart from its surrounding area.

2. How do the populations of your mini-ecosystems compare?

3. Identify some of the adaptations that the organisms living in your two mini-ecosystems have. Describe how the adaptations help the organisms survive intheir environment.

DRAW CONCLUSIONS

4. Write a report describing and comparing your mini-ecosystems with those ofyour classmates.

ANSWER KEY



Name Class Date

Discovering Mini-Ecosystems continued

Students may have many answers, but they should include answers such as

different vegetation, organisms that live there, the soil type, density of

vegetation, and amount of water present.

Students should recognize that the populations present in each area are

adapted for life in that area.

Adaptations that students name will probably include camouflage, deep

roots, and burrowing behavior.

Answers may vary according to student observations.

1 2 3 4Easy Hard






MATERIALS

You may want to have students bring in articles for several days prior to doingthis activity. You might also want to limit students’ choices to those that are age-appropriate.

LAB NOTES

This lab can be repeated as environmental issues appear in the news. You maywish to combine this activity with a video that portrays an international environmental issue. Students can also be encouraged to use the Internet as asource of information.


ANSWER KEY



Debra SampsonBooker T. Washington Middle School

Elgin, Texas


Holt Science and Technology 62 Environmental Problems and SolutionsCopyright © by Holt, Rinehart and Winston. All rights reserved.


ANSWER KEY

You make hundreds of decisions every day. Some of them are complicated, butmany of them are very simple, such as what to wear or what to eat for lunch.Deciding what to do about an environmental issue can be very difficult. There aremany different factors that must be considered. How will a certain solution affectpeople’s lives? How much will it cost? Is it ethically right?

In this activity, you will analyze an issue in four steps to help you make a decision about it. Find out about environmental issues that are being discussed inyour area. Examine newspapers, magazines, and other publications to find outwhat the issues are. Choose one local issue to evaluate. For example, you couldevaluate whether the city should spend the money to provide recycling bins andspecial trucks for picking up recyclable trash.

MATERIALS

• newspapers, magazines, and other publicationscontaining information about environmental issues

PROCEDURE

1. Write a statement about an environmental issue.

2. Read about your issue in several publications. Ona separate sheet of paper, summarize importantfacts.

3. The values of an issue are the things that youconsider important. Examine the diagram below.Several values are given. Which values do you think apply most to the envi-ronmental issue you are considering? Are there other values that you believewill help you make a decision about the issue? Consider at least four values inmaking your decision.

Name Class Date


Environmentaldecisions

What is beautifulor pleasing

Provides funactivities

Knowledge gainedby research

Respects traditionsof a community

Affects people'shealth

What is rightor wrong

Protects naturalresources

Gain or loss ofmoney or jobs

A Four-StepDecision-Making Model

Gather Information

▼Consider Values

▼Explore Consequences

▼Make a Decision



4. Consequences are the things that result from a certain course of action. Createa table similar to the one below. Use the data table below to organize yourthoughts about consequences related to your environmental issue. List yourvalues at the top. Fill in each space with the consequences for each value.

Consequences TableValues

Consequences

Positive short-termconsequences

Negative short-termconsequences

Positive long-termconsequences

Negative long-termconsequences

5. Thoroughly consider all of the consequences you have recorded in your table.Evaluate how important each consequence is. Make a decision about whatcourse of action you would choose on the issue.

ANALYZE THE RESULTS

1. In your evaluation, did you consider short-term consequences or long-termconsequences to be more important? Why?

2. Which value or values had the greatest influence on your final decision?Explain your reasoning.


Compare your table with your classmates’ tables. Did you all make the same deci-sion about a similar issue? If not, form teams, and organize a formal classroomdebate of a specific environmental issue.

ANSWER KEY



Name Class Date

Deciding About Environmental Issues continued

Either short- or long-term consequences can be more relevant, depending on

the issue.

Encourage students to narrow their topic to a single aspect of an issue, such

as the importance of aesthetic value in the preservation of natural areas.

Answers may vary according to students’ perspectives.






SAFETY CAUTIONA digital thermometer that measures temperature from the ear is recommended.

Because of the vigorous nature of the exercise, you may want to ask forvolunteers to do the exercising. Also, you should be aware of any health concernsyour students have.


ANSWER KEY



Kathy LaRoeEast Valley Middle School

East Helena, Montana

1 2 3 4Easy Hard


Holt Science and Technology 73 Body Organization and StructureCopyright © by Holt, Rinehart and Winston. All rights reserved.


ANSWER KEY

Have you ever exercised outside on a cold fall day wearing only a thin warm-upsuit or shorts? How did you stay warm? The answer is that your muscle cells contracted, and when contraction takes place, some energy is used to do work,and the rest is converted to thermal energy. This process helps your bodymaintain a constant temperature in cold conditions. In this activity, you will learnhow the release of energy can cause a change in your body temperature.

MATERIALS


• thermometer, small, hand held

• other materials as approved by your teacher

ASK A QUESTION

1. Write a question that you can test about how activity affects body temperature.

FORM A HYPOTHESIS

2. Form a group of four students. In your group, discuss several exercises thatcan produce a change in body temperature. Write a hypothesis that couldanswer the question you asked.

TEST THE HYPOTHESIS

3. Develop an experimental procedure that includes the steps necessary to testyour hypothesis. Be sure to get your teacher’s approval before you begin.

4. Assign tasks to individuals in the group, such as note taking, data recording,and timing. What observations and data will you be recording? Design yourdata tables accordingly.

5. Perform your experiment as planned by your group. Be sure to record allobservations in your data tables.

Name Class Date





ANALYZE THE RESULTS

1. How did you determine if muscle contractions cause the release of thermalenergy? Was your hypothesis supported by your data? Explain your results ina written report. Describe how you could improve your experimental method.

APPLYING YOUR DATA

Why do humans shiver in the cold? Do all animals shiver? Find out why shiveringis one of the first signs that your body is becoming too cold.

ANSWER KEY



Name Class Date

Muscles at Work continued

Sample answer: In a process known as shivering thermogenesis, muscle tone is

gradually increased. Shivering increases the workload of the muscles and

elevates oxygen and energy consumption. The heat that is produced warms the

deep vessels. Shivering can elevate body temperature effectively. It can increase

the rate of heat generation by as much as 400%. Endothermic animals have the

capacity to shiver. Shivering is an automatic response of the body to cold.

All answers will depend on the students’ observations and their own

hypotheses.


Holt Science and Technology 91 Circulation Circulation and Respiration




MATERIALS

You may want to build a model first to use as a reference for students. If so, youmay want to substitute a bag smaller than the one that students use to model thediaphragm.


ANSWER KEY



Yvonne BrannumHine Junior High School

Washington, D.C.

1 2 3 4Easy Hard


Holt Science and Technology 77 Circulation and RespirationCopyright © by Holt, Rinehart and Winston. All rights reserved.


ANSWER KEY

When you breathe, you actually pull air into your lungs because your diaphragmmuscle causes your chest to expand. You can see this is true by placing yourhands on your ribs and inhaling slowly. Did you feel your chest expand? In thisactivity, you will build a model of a lung by using some common materials. Youwill see how the diaphragm muscle works to inflate your lungs. Refer to the diagrams in the textbook as you construct your model.

MATERIALS

PROCEDURE

1. Attach the balloon to the end of the straw with a rubber band. Make a holethrough the clay, and insert the other end of the straw through the hole. Besure at least 8 cm of the straw extends beyond the clay. Squeeze the ball ofclay gently to seal the clay around the straw.

2. Insert the balloon end of the straw into the neck of the bottle. Use the ball ofclay to seal the straw and balloon into the bottle.

3. Turn the bottle gently on its side. Place the trash bag over the cut end of thebottle. Expand a rubber band around the bottom of the bottle to secure thebag. You may wish to reinforce the seal with tape. Before the plastic is completely sealed, gather the excess material of the bag into your hand, andpress toward the inside of the bottle slightly. (You may need to tie a knotabout halfway up from the bottom of the bag to take up excess material.) Usetape to finish sealing the bag to the bottle with the bag in this position. Theexcess air will be pushed out of the bottle.

ANALYZE THE RESULTS

1. What can you do with your model to make the “lung” inflate?

2. What do the balloon, the plastic wrap, and the straw represent in your model?

Name Class Date


• bag, trash, small plastic

• balloon, small

• bottle, top half, 2 L

• clay, golf-ball-sized piece

• rubber bands (2)

• ruler, metric

• straw, plastic

• tape, transparent

The balloon will inflate when the plastic bag is pulled down.

The balloon represents a lung, the plastic wrap represents a diaphragm, and

the straw represents a trachea. (Students may also note that the bottle

represents the part of the body in which the lungs are located.)



3. Using your model, demonstrate to the class how air enters the lung and howair exits the lung.

APPLYING YOUR DATA

Do some research to find out what an “iron lung” is and why it was used in thepast. Research and write a report about what is used today to help people whohave difficulty breathing.

ANSWER KEY



Name Class Date

Build a Lung continued

From the late 1920s to the 1950s, iron lungs were used to treat respiratory

paralysis due to poliomyelitis. The patient was encased within an airtight

chamber from the neck down. A large set of leather bellows mounted in a

separate pumping unit expanded, causing pressure changes inside the

chamber. This in turn caused the chest of the patient to expand, drawing

fresh air into the lungs through the mouth. Now, several models of portable

ventilators allow patients much more freedom to move about.

Air enters the lungs when the diaphragm moves down and creates more

space inside the chest cavity. Air is forced out of the lungs when the

diaphragm moves up. Students should demonstrate this process by moving

the plastic bag up and down.



Teacher Notes and Answer KeyTime Required



MATERIALSThe materials listed on the student page are enough for 1 student or a group of 2to 4 students. If you do not have enough mortar and pestles or small plates, youmay have students use any small container to mash the liver with a fork. Beefliver is readily obtained at the grocery store.

SAFETY INFORMATION

Safety Caution: Remind students to review all safety cautions and icons beforebeginning this lab activity. Use a dilute solution of hydrogen peroxide. Hydrogenperoxide can be harmful to skin and clothing. Caution students to be careful notto spill or splatter the solution while pouring. If hydrogen peroxide comes intocontact with skin, wash the skin immediately with plenty of running water.


ANSWER KEY



James ChinFrank A Day Middle SchoolNewtonville, Massachusetts

1 2 3 4Easy Hard

You know how important enzymes are in the process of digestion. This lab willhelp you see enzymes at work. Hydrogen peroxide is continuously produced byyour cells. If it is not quickly broken down, hydrogen peroxide will kill your cells.Luckily, your cells contain an enzyme that converts hydrogen peroxide into twononpoisonous substances. This enzyme is also present in the cells of beef liver. Inthis lab, you will observe the action of this enzyme on hydrogen peroxide.

MATERIALS

SAFETY INFORMATION

PROCEDURE

1. Use the data table below to record your observations.

Data Table

Size andcondition

ExperimentalObservations

of liver liquid

1 cm cubebeef liver 2 mL water

1 cm cube 2 mL hydrogenbeef liver peroxide

1 cm cube2 mL hydrogenbeef liver

peroxide(mashed)

2. Get three equal-sized pieces of beef liver from your teacher, and use yourforceps to place them on your plate.

3. Pour 2 mL of water into a test tube labeled “Water and liver.”

4. Using the tweezers, carefully place one piece of liver in the test tube. Recordyour observations in your data table.


Holt Science and Technology 56 The Digestive and Urinary SystemsCopyright © by Holt, Rinehart and Winston. All rights reserved.


ANSWER KEY

Name Class Date


• beef liver, 1 cm cubes (3)



• hydrogen peroxide, fresh (4 mL)

• mortar and pestle (or fork and watchglass)

• plate, small

• spatula

• test tube (3)

• test-tube rack

• tweezers

• water



5. Pour 2 mL of hydrogen peroxide into a second test tube labeled “Liver andhydrogen peroxide.”

Caution: Do not splash hydrogen peroxide on your skin. If you do get hydro-gen peroxide on your skin, rinse the affected area with running water immedi-ately, and tell your teacher.

6. Using the tweezers, carefully place one piece of liver in the test tube. Recordyour observations of the second test tube in your data table.

7. Pour another 2 mL of hydrogen peroxide into a third test tube labeled“Ground liver and hydrogen peroxide.”

8. Using a mortar and pestle (or fork and watch glass), carefully grind the thirdpiece of liver.

9. Using the spatula, scrape the ground liver into the third test tube. Record yourobservations of the third test tube in your data table.

ANALYZE THE RESULTS

1. What was the purpose of putting the first piece of liver in water? Why wasthis a necessary step?

2. Describe the difference you observed between the liver and the ground liverwhen each was placed in the hydrogen peroxide. How can you account forthis difference?

ANSWER KEY



Name Class Date


Sample answer: The piece of liver in water. A control is necessary so that

differences in reactions to other substances can be observed.

Students should observe that the cube of liver produced a quick, foaming

reaction to the hydrogen peroxide as the solution came into contact with the

cells and destroyed them. The mashed liver should also produce a very quick

reaction; however, students should observe that the effervescence subsides

faster than with the mashed liver than with the cube. The reason is that the

mashed liver has a greater surface area than the cube, exposing more liver

enzymes to the hydrogen peroxide. There should be no reaction in water.



APPLYING YOUR DATA

Do plant cells contain enzymes that break down hydrogen peroxide? Try thisexperiment using potato cubes instead of liver to find out.

ANSWER KEY



Name Class Date


Students will discover that plant cells do contain enzymes that will break down

hydrogen peroxide. Have them experiment with different types of plants and

vegetables so they can observe the different rates of reaction.







ANSWER KEY



Randy ChristianStovall Junior High School

Houston, Texas1 2 3 4Easy Hard


Holt Science and Technology 66 Reproduction and DevelopmentCopyright © by Holt, Rinehart and Winston. All rights reserved.


ANSWER KEY

In humans, the process of development that takes place between fertilization andbirth lasts about 266 days. In 4 weeks, the new individual grows from a single fer-tilized cell to an embryo whose heart is beating and pumping blood. All of theorgan systems and body parts are completely formed by the end of the seventhmonth. During the last 2 months before birth, the baby grows, and its organ sys-tems mature. At birth, the average mass of a baby is about 33,000 times as muchas that of an embryo at 2 weeks of development! In this activity, you will discoverjust how fast a fetus grows.

MATERIALS

• paper, graph

• pencils, colored

PROCEDURE

1. Using graph paper, make two graphs—one entitled “Length” and one entitled“Mass.”On the length graph, use intervals of 25 mm on the y-axis. Extend they-axis to 500 mm. On the mass graph, use intervals of 100 g on the y-axis.Extend this y-axis to 3,300 g. Use 2-week intervals for time on the x-axes forboth graphs. Both x-axes should extend to 40 weeks.

2. Examine the data table on the next page. Plot the data in the table on yourgraphs. Use a colored pencil to draw the curved line that joins the points oneach graph.

ANALYZE THE RESULTS

1. Describe the change in mass of a developing fetus. How can you explain thischange?

2. Describe the change in length of a developing fetus. How does the change inmass compare to the change in length?

Name Class Date


Students’ graphs should look like those at the bottom of the next page.

The change in mass of a developing fetus is steadily increasing, approxi-

mately tripling each month of the first and second trimesters. This period is

one of rapid cell division.

Fetal length steadily increases, doubling and even tripling each month in the

first two trimesters. In the third trimester, the rate of lengthening slows.

Mass continues to increase, even in the last trimester.



INCREASE OF MASS AND LENGTH OF AVERAGE HUMAN FETUS

Time (weeks) Mass (g) Length (mm)2 0.1 1.53 0.3 2.34 0.5 5.05 0.6 10.06 0.8 15.08 1.0 30.013 15.0 90.017 115.0 140.021 300.0 250.026 950.0 320.030 1,500.0 400.035 2,300.0 450.040 3,300.0 500.0

APPLYING YOUR DATA

Using the information in your graphs, estimate how tall a child would be at age 3if he or she continued to grow at the same average rate that a fetus grows.

ANSWER KEY



Name Class Date

My, How You’ve Grown! continued

Students’ graphs should look like these.

The child would be 2.45 m (8.04 ft) tall!

0

4 8 12 16 20 24 28 32 36

300

600

900

1200

1500

1800

2100

2400

2700

3000

3300

Mass Length

Time (weeks)

4 8 12 16 20 24 28 32 36

Time (weeks)

Leng

th (

mm

)

Mas

s (g

)

050

100150200250300350400450500

40 40




Two 45-minute class periods


MATERIALS

A copy of a chart that fast-food restaurants post in their dining rooms outlining the nutritional information of the food they serve would be very helpful in analyzing a fast-food meal.


ANSWER KEY



Ivora WashingtonHyattsville Middle School

Hyattsville, Maryland1 2 3 4Easy Hard


Holt Science and Technology 73 Staying HealthyCopyright © by Holt, Rinehart and Winston. All rights reserved.


ANSWER KEY

There are six main classes of foods that we need in order to keep our bodiesfunctioning properly: water, vitamins, minerals, carbohydrates, fats, and proteins.In this activity you will investigate the importance of a well-balanced diet inmaintaining a healthy body. Then you will create a poster or picture that illus-trates the importance of one of the three energy-producing nutrients—carbohy-drates, fats, and proteins.

MATERIALS

PROCEDURE

1. Look at the table below. Research in the library, on nutrition labels, in nutri-tion or diet books, or on the Internet to find the information you need to fillout the chart.

NUTRITION DATA TABLE

Fats Carbohydrates Proteins

Found in which foods

Functions in the body

Consequences of deficiency

Name Class Date


• crayons (or markers), assortedcolors

• diet books

• menus, fast-food (optional)

• nutrition reference books

• paper, white unlined



2. Choose one of the foods you have learned about in your research, and createa poster or picture that describes its importance in a well-balanced diet.

ANALYZE THE RESULTS

1. Based on what you have learned in this lab, how might you change youreating habits to have a well-balanced diet? Does the nutritional value of foodsconcern you? Why or why not? Write down your answers, and explain yourreasoning.


Write a paragraph explaining why water is a nutrient. Analyze a typical fast-foodmeal, and determine its overall nutritional value.

ANSWER KEY



Name Class Date

To Diet or Not to Diet continued

Answers may vary. Students may say they might try to eat fewer fatty

foods. The nutritional value of foods is a subject that may be new to many

students.

Sample answer: Without water, most of the reactions that maintain life could

not take place. Water carries the other essential nutrients to all parts of the

body and is the medium in which waste products are dissolved and carried away

from body tissues.

Answers will vary depending on the type of meal a student chooses. Fast-food

restaurants usually post Nutrition Facts in public view. Have students obtain

this information and evaluate a fast-food meal based on those Nutrition Facts

and daily recommended amounts. Examining the Nutrition Facts labels on food

packaging is helpful before beginning this activity.

Documents

Leaf Me Alone Labbook[1]