Chapter 1

Mystery Worms

Section 1-2

Interest Grabber

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A teacher collected some beetles from a rotting log and placed them in a container of dry oatmeal in her classroom. She kept the box covered with a light cloth so that the beetles could not escape. She also asked one of her students to add potato and apple pieces once a week to provide food and moisture for the beetles. After several weeks, the student reported that there were some strange-looking, wormlike organisms in the container.

• 1. Formulate a hypothesis that might explain the presence of the “worms” in the container.

• 2. How could you test your hypothesis?

• 3. Identify the variables in your proposed experiment. Identify the control in your proposed experiment.

Section 1-2

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Designing an Experiment

Section 1-2

Flowchart

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State the Problem

Form a Hypothesis

Set Up a Controlled Experiment

Record Results

Analyze Results

Draw a Conclusion

Publish Results

OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat.

HYPOTHESIS: Flies produce maggots.PROCEDURE

Controlled Variables:jars, type of meat,location, temperature,time

Manipulated Variables:gauze covering thatkeeps flies away from meat

Uncovered jars Covered jars

Several days pass

Maggots appear No maggots appearResponding Variable: whether maggots appear

CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur.

Section 1-2

Figure 1-8 Redi’s Experiment on Spontaneous Generation

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Shells and Snowflakes

• How can we distinguish between living and nonliving things, such as a radiolarian (left) and a snowflake (right)? A radiolarian is a tiny living thing that is covered with a glasslike shell and lives in the ocean. A snowflake is a crystal made of frozen water.

Section 1-3

Interest Grabber

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• Work with a partner to answer the following questions.

• 1. What are some similarities between the snowflake and the glass shell of the radiolarian?

• 2. What are some differences between the snowflake and the glass shell?

• 3. Would you classify the shell as a living thing or a nonliving thing?

• Explain your answer.

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• 1–3 Studying LifeA. Characteristics of Living Things

1. Made Up of Cells

2. Reproduction

3. Based on a Genetic Code

4. Growth and Development

5. Need for Materials and Energy

6. Response to the Environment

7. Maintaining Internal Balance

8. Evolution

B. Branches of Biology-zoologist, botanist, paleotologist, marine biologist, ecologist, molecular biologist

Section 1-3

Section Outline

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Organism

Groups ofCells

Cells

Molecules

Individual livingthing

Tissues, organs,and organ systems

Smallest functionalunit of life

Groups of atoms;smallest unit of most chemicalcompounds

Bison

Nervous tissue Nervous systemBrain

Nerve cell

Water DNA

Section 1-3

Figure 1-21 Levels of Organization continued

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