Science 14 Unit D: Matter & Energy in the Biosphere

Chapter 12

The Web of Life pp. 236-253

WORKBOOK

Name: _____________________________

1

12.1 – What is Energy? pp. 238-239

• Energy is not a substance (no mass and doesn’t take up space)

o Energy is a property or quality that provides ability to move or do work causes change cannot be created nor destroyed, only converted (Law of Conservation)

• Food contains chemical potential energy, which fuels life processes

See Figure 12.1 & 12.2 – p. 238

carbon dioxide + water + energy ⇄ oxygen + glucose (sugar)

Photosynthesis Cellular Respiration occurs only in plants occurs both in plants and animals uses CO2(g) and H2O(l) produces CO2(g) and H2O(l) uses energy in the form of light (radiant and solar)

produces energy in the form of heat or movement

produces glucose (chemical energy) uses glucose or other forms of chemical energy

produces oxygen as a waste product uses oxygen converts small molecules into large ones, using energy

converts large molecules into smaller ones, releasing energy

• All energy ultimately comes from the Sun

o Green plants capture light energy from the Sun during photosynthesis where it is converted to chemical energy by making a sugar called glucose

Read “Did You Know” - p. 238 Discuss CYU – p. 239 #1-3

Photosynthesis

Cellular Respiration

2

Joseph Priestley’s Experiment BLM 12-1

In 1774, Joseph Priestley set up three jars filled with air. He placed a mouse in Jar 1 and a plant in Jar 2. In Jar 3, he placed a mouse and a plant together. He sealed all three jars. 1. What gases are in air?

2. What do you think will happen to the mouse in Jar 1? To the plant in Jar 2?

3. The mouse in Jar 1 had trouble breathing after 20 minutes. Why?

4. The plant in Jar 2 lived for several days, but did not grow any bigger. Why? 5. What do you think happened to the mouse and plant in Jar 3? Why?

Jar 1 Jar 2 Jar 3

3

12.2 – Storing Energy from the Sun pp. 240-241

• Plants use energy from glucose for life activities

• If more sugar is produced than they need, plants store excess glucose as starch

o Starch is stored in the leaves, stems, seeds, and roots

o Other living organisms consume starch when they each carbohydrate foods

o Starch is broken down into glucose during digestion

Glucose is subsequently used for cellular respiration in the mitochondria

of the cells to release the stored chemical energy needed to support life

functions

Discuss CYU – p. 241 #1-3

4

12.3 – Energy Pathways in an Ecosystem pp. 242-244

• Ecosystems communities of living things and the environment they live in.

o They contains: 1. living things (plants, animals, bacteria, etc.) 2. non-living things (rocks, weather, water, etc.)

• All things in an ecosystem are interrelated

o if one thing is changed it is all changed

• Energy flows from one level in it to the next.

o The first level gets energy from the sun producers Example: green plants Create glucose with photosynthesis energy is passed to other organisms in the ecosystem

o plants are eaten by herbivore animals

primary consumers Example: deer

o primary consumers are then eaten by carnivores (meat eaters)

secondary consumer Example: wolves

• The transfer of energy form one level to the next is called the food chain. o The food chain is a step by step sequence of who eats whom,

begins with a producer Each organism gets energy from the one before it in the chain. Arrows are drawn to show the direction of energy flow.

• The arrow points from the organism being eaten to the organism doing the eating.

Example: Sun grass mouse snake hawk

Energy producer primary consumer secondary consumer tertiary consumer

5

• Food webs are series of interlocking food chains, showing the transfer of energy through various levels of an ecosystem.

o It is more complex and realistic than a food chain because most organisms are consumed by several other types of organisms, not just one.

o In a food web, a change in one thing will affect almost everything else because they are all connected in some way (all interconnected)

• Decomposers consume the waste materials, like dead/decaying animals.

This is an example of an aquatic food web:

Discuss CYU – p. 244 #1-2

6

Food Web Activity BLM 12-4

Create a food web with the organisms below by using arrows to indicate the flow of energy from one organism to another in this ecosystem.

7

12.4 – Energy Transfers pp. 245-247

• The most energy in the chain is at the beginning, the producers.

Ecological Pyramid

• pyramid of energy shows the total amount of chemical energy that flows through each feeding level in an ecosystem

• As you move up the chain, each organism uses up energy for its own growth and life processes. Some energy is also lost as heat.

• Only about 10% of the total energy originally consumed at each level is available to

the organism that eats it in the next level o the other 90% is NOT available (lost to an unusable form of energy) o That is why there are fewer organisms in the top level of the energy pyramid

Discuss INV 12-B – p. 246 #1-5

Discuss CYU – p. 247 #1-4

8

12.5 – The Cycles of Matter p. 248

• The Sun is the driving force behind all cycles of matter o Each year, producers convert more than 10% of the total carbon dioxide in the

atmosphere into sugars

• Matter recycles in nature

The Water Cycle

• Water evaporates constantly from streams, lakes, and the bodies of organisms • This cycle maintains fresh-water environments and supplies the vast quantities of

water necessary for life on land

9

The Carbon and Oxygen Cycle

• These gases cycle during the processes of photosynthesis and cellular respiration

o See Section 12.1 Notes

• Decomposers use oxygen to break down dead organisms and animal waste

o They return carbon dioxide to the atmosphere

10

The Nitrogen Cycle

• Nitrogen is an important nutrient that all organisms need for growth

• Certain bacteria, and even lightning, convert nitrogen gas to nitrate forms that are useful for plants

• Plants and animals die and decay

o The compounds in their bodies that contain nitrogen are converted by other bacteria to make nitrates

o The nitrates are used again by plants or returned to the atmosphere as nitrogen gas

• It is estimated that about 50% of all household waste could be composted! • Decomposing plant and animal waste contain nitrates and other nutrients

o One hundred years ago, farms spread these on the soil to help plants grow

• A mixture of decomposing plants and soil is called compost o Today may people add this to their house plants, lawns, or gardens o Composting is one way to recycle yard and kitchen wastes and reduce the

volume of garbage sent to landfills for disposal

Discuss CYU – p. 251 #1-4

11

Recycling Energy Crossword BLM 12-11

12

Across

4. eats primary consumers (2 words) 7. the basic life process used by living things to release energy stored in glucose

(2 words) 10. organisms that produce the chemical energy used by an ecosystem 13. a diagram that shows how much energy is transferred from each level in a food chain

to the next (3 words) 14. a diagram of several food chains together (2 words) 15. a simple diagram showing who eats whom in an ecosystem (2 words) 16. decomposed plant matter that you can make and use to help plants grow 17. a diagram that shows the relative number of organisms or the amount of energy at

each feeding level (2 words) 18. Plants make this and store it as starch. 19. a diagram showing what happens to nitrogen in the environment (2 words) 20. an organism that eats producers (2 words) Down

1. the process used by plants to capture the Sun’s energy 2. how water, carbon, and oxygen move throughout the planet and its organisms 3. organisms that take the last remaining energy from dead plants and animals and their

wastes 5. any organism that is not a producer 6. what Earth receives from the Sun 8. eats secondary consumers (2 words)

9. cycle that includes evaporation, condensation, and precipitation (2 words) 11. a biological community and its physical environment 12. a diagram showing the movement of carbon throughout the environment (2 words)

13

Chapter 12 Review Questions

1. Describe some differences in the ways humans travelled, lived, and produced and acquired food over the past 100 years. Why have the techniques and technologies changed? What ecological problems have been created because of changed methods? (12.1)

2. Define “energy.” (12.1) 3. List as many types of energy as you can. Give an example of each. (12.1) 4. Explain the relationship between glucose and starch in plants. Why do plants need to

store starch? Research to discover how and why animals store chemical energy. (12.2) 5. Draw a food chain that you would find in your area. Include drawings of the

organisms. Label each organism with its role. Draw a pyramid of numbers and a pyramid of energy for your food chain. (12.3 & 12.4)

6. Draw a food web that includes your food chain. (12.3 & 12.4) 7. List how the energy contained in the tissues of a live mouse can be transferred to other

organisms. Account for all the energy. (12.4)

14

Complete Chapter 12 Review Questions – p. 252 #1-8 Please record your answers below or on an attached sheet of loose leaf.