Science 14 Unit D: Matter & Energy in the Biosphere

Chapter 15 Protecting the Environment

pp. 290-307

WORKBOOK

Name: _____________________________

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15.1 – Producing More Food pp. 292-296

biodegradable any material that can be broken down by organisms in the environment

• Include any organic matter from organisms that were once living • Example: paper, food waste, etc.

non-biodegradable materials that break down very slowly or not at all

• Example: plastics, glass, metal, etc.

• As the human population increase, more and more food is needed • Farmers grow as much food as they can each year

o Earth has a limited amount of suitable (and available) land for agriculture o Farmers use technology to help them grow more food o There are consequences that go with the benefit of producing more food

• Scientists have developed two major chemicals to help increase food production, which include pesticides and synthetic (man-made) fertilizers.

• Pesticides chemicals that kill or control organisms that humans consider to be

pests (unwanted organisms) o Insecticides kill insects o Herbicide kill weeds (unwanted plants)

Read “Did You Know” – p. 293

Resistance – sometimes organisms have natural resistance to herbicides and pesticides • i.e. the chemical doesn’t kill them • This genetic characteristic is passed on to their offspring, eventually creating an

entire population of resistant pests (inherited immunity)

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Pest Resistance BLM 15-4 Imagine that the individuals in each oval are pests of a single species. Some individuals are killed by DDT while others are not affected.

1. What happens to the number of resistant individuals after a few generations? Why? 2. What happens to the number of non-resistant individuals after a few generations? Why?

3. What factor caused the change in the resistance of the pests? Name three ways in which humans vary from one another, despite being the same species

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15.1 – Producing More Food continued

• Biological Magnification (see Figure 15.1 – p. 292) o The toxic effect of pesticide chemicals increases in organisms as you move

further along a food chain and the concentrations magnify o i.e. individuals at the top of a food pyramid (tertiary consumers) can be

indirectly affected by chemicals through the foods they eat

• Synthetic Fertilizer contains nutrients, such as nitrates, that plants need o Increase crop yields (grow more food on the same amount of land) o The natural nitrogen cycle (p. 250) is balanced between the producers,

consumers, and soil, however, it can be disrupted by human activity Algae growth increases due to nitrates from fertilizers that are washed

into waterways from farms, golf course, and lawns Eutrophication buildup of nutrients in an aquatic ecosystem

Discuss Figure 15.4 – p. 296

Discuss CYU – p. 296 #1-4

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DDT in the Food Chain BLM 15-2

Analyze the effect of DDT on peregrine falcon populations. When scientists first developed DDT, they thought it was a safe pesticide for killing insects. People used DDT to control populations of lice, fleas, mosquitoes, and crop-eating insects. But DDT does not break down easily — instead, it accumulates in organisms. When other organisms eat contaminated organisms, they become contaminated as well. The amount of DDT in an organism increases as you move along the food chain. Although primary consumers are only slightly contaminated, secondary and tertiary consumers are more and more contaminated. This process is called biological magnification. Eventually, DDT concentrations become large enough to affect the reproduction of birds of prey such as the peregrine falcon. Peregrine falcons with high levels of DDT lay thin-shelled eggs. The shells are so thin that the eggs are either crushed during incubation or simply do not hatch. Over several years, this causes a dramatic decrease in the birth rate of these birds. Before 1970, for example, numbers of peregrine falcons declined dramatically throughout North America. DDT was banned in Canada in 1969 and in the United States in 1972. Since then, several captive-breeding programs have been operated throughout North America. These programs have been used to return peregrine falcons to places where they used to be common. In 1996, about 65 percent of the population of peregrine falcons in southern Alberta were bred in captivity. Study the graph to see the slow recovery process of the peregrine falcon population in Alberta.

What to Do Read the information on DDT and study the graph showing the population of peregrine falcons in Alberta between 1970 and 1996.

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What Did You Discover? 1. Draw two food chains that might include peregrine falcons.

2. Why was DDT used in North America?

3. From the textbook and graph, describe what happened to the population of peregrine falcons in the

1960s and 1970s. 4. What do you think would have happened to these birds if DDT had not been banned in North

America?

5. (a) Read the graph and then explain what happened to the population of falcons in the 1990s.

(b) What do you think will happen to the population of falcons in the next five years?

6. The accumulation of pesticides in a food chain is called biological magnification. Use DDT and the peregrine falcon to explain how pesticides can accumulate in a food chain. You can do this in words or by using a series of diagrams

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15.2 – Producing More Energy pp. 297-298

• Energy demands increase as the human population increase

o Vehicles, electricity, heat, etc. o In Alberta, most of the energy we need is produced from fossil fuels

includes coal, oil, and natural gas formed from the remains of organisms that lived millions of years ago See Figure 15.5 – p. 297

• greenhouse effect is caused from heat being trapped by carbon dioxide and other

atmospheric gases o excess CO2(g) makes this “blanket” thicker and prevents more heat from

escaping into space without carbon dioxide in the atmosphere, Earth’s average surface

temperature would be –18°C o Global Warming is a theory that over time the increase it greenhouse gases

(excess from burning fossil fuels, etc.) will cause the Earth’s average temperature to increase, which could have serious consequences! Melting polar ice caps Drastic changes to weather system Cause droughts on agricultural lands

o Global Climate Change is another commonly accepted theory related to the effect of increased greenhouse gases from human activity

Discuss CYU – p. 298 #1-5

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15.3 – Producing More Products pp. 299-301

• A lot of the food luxuries we enjoy today, like ice cream and fresh fruit, depend on

the technology of refrigeration • The refrigerator was invented in 1803 but was not used as a household appliance

until the twentieth century • Before refrigeration food was salted, dried, canned, or kept in cold cellars, well, or

streams to be preserved o This process did not work well on all foods and did not always prevent

bacteria from growing o Food spoilage was common and many people died from food poisoning

Discuss Figures 15.6 & 15.7 – p. 299

• See Figure 5.20 – p. 101 for an explanation of how refrigerators work

o a compressor and a motor is used to move the liquid refrigerant that removes heat from the appliance

o CFC’s (chlorofluorocarbons) is a type of refrigerant discovered in the 1920s that is safer for household use because it is stable and non-combustible scientists later discover that CFCs have a negative effect on the

atmosphere’s ozone layer • organisms, including humans, can be seriously harmed by the

thinning of the ozone layer – see Figures15.8-15.10 – p. 301 o more people develop skin cancer due to increased

exposure to UV rays o high levels of UV radiation slows growth of major crops

Discuss CYU – p. 301 #1-4

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TASK: Complete Investigation 15B – p. 300 #1-5

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Ozone Depletion Mechanism BLM 15-7

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15.4 – Why So Much Waste? pp. 302-303

• each Canadians discard about 2.2 kg of garbage every day

o this is more waste per person than most other nations in the world and probably due to our high standard of living

• garbage ends up in landfills to prevent waste materials from harming the

environment see Figure 15.11 – p. 302

• to help the environment we should always make a conscious effort to reduce, re-use, and recycle

Discuss Figures 15.12-15.14 – p. 303 Read “Did You Know” – p. 303 Discuss CYU – p. 303 #1-3

15.5 – What Can We Do? pp. 304-305

• humans can also have a positive impact on the environment

• many people and groups are working to reverse the problems created by human activity and restore the environment

o Dave Matheson is a habitat specialist with Ducks Unlimited in Grand Prairie Read “Career Connect” – p. 304 Discuss CYU – p. 305 #1-2

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Saving Energy Worksheet Find Out Activity – p. 302

It takes a lot of electrical energy to manufacture a pop can from bauxite (aluminum ore). It takes much less energy to make a new pop can from recycled aluminum can. The amount of energy saved by recycling one aluminum can will power your television for 2 hours!

Number of students in your class = _____ Number of cans thrown out in one day (at one per student) = _____ How long will your television run using the energy saved by recycling one day’s cans? 2 x ______ (# of cans) = ______ hr Number of cans thrown out per week, at one per student per day: 7 days x _____ cans per day = _____ How long will your television run using the energy saved by recycling one week’s cans? 2 x ______ (# of cans) = ______ hr

1. How does recycling pop cans help reduce the amount of waste energy entering a landfill?

2. How does recycling pop cans reduce the amount of electricity we use?

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Protecting the Environment Crossword

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Across

1. Apply this to the soil to increase crop yield.

3. marshy areas that remain wet all year

10. the buildup of nutrients in an aquatic ecosystem

11. the liquid used to remove heat from a refrigerator

13. Drainage ditches are blocked and dams built to allow the land to flood.

14. the abbreviation for chlorofluorocarbons

15. describes anything that can be broken down by decomposers

16. an increase in Earth’s average temperature (2 words)

17. to look for different uses for something you might throw away

18. when heat is trapped in the atmosphere due to increased concentrations of carbon dioxide (2 words)

19. used to kill weeds

20. to lessen the amount of waste you produce

21. an invisible layer of gas in the atmosphere about 15–35 km above Earth’s surface (2 words) Down

2. a chemical designed to kill insects

4. chemicals that kill or control organisms that humans do not want

5. to allow a container or other materials to be made into something else

6. a site developed to prevent waste materials from harming the environment

7. when individuals have a tolerance for something that kills most other individuals in the population

8. formed from the remains of organisms that lived millions of years ago (2 words)

9. when a chemical is found in higher concentrations in carnivores than in primary consumers (2 words)

12. describes materials that break down very slowly or not at all

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Chapter 15 Review Questions 1. What is the difference between biodegradable and non-biodegradable? (p. 291)

2. Many years ago, an insecticide called DDT was used. Unfortunately, this insecticide damaged or killed other animals in the food web. What term is used for the movement of pesticides through a food web? (15.1)

3. Explain what fossil fuels are. What effect do they have on the environment? (15.2)

4. What causes the greenhouse effect? (15.2)

5. CFCs (chlorofluorocarbons) are dangerous to the atmosphere. Explain what they do to the atmosphere and why this is dangerous. (15.3)

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6. What is a landfill site? (15.4)

7. List at least three ways you could reduce, re-use, or recycle to help the environment. (15.4)

8. How are wetlands beneficial? (15.5)

9. What is meant by wetlands restoration? (15.5)

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Complete Chapter 15 Review Questions – p. 306 #1-10 Please record your answers below or on an attached sheet of loose leaf.