1. Chapter 2: Energy Flow and Nutrient Cycles Support Life in Ecosystems

2. Match the term on the left with the descriptor on the right. 1
Match the term on the left with the descriptor on the right. 1. Cellular respiration 2. denitrification 3. nitrification 4. nutrients 5. photosynthesis 6. sedimentation 7. weathering
A. nitrogen is released into atmosphere
B. Substances (N and P) are required by plants/animals for energy, growth, development, repair, maintenance
C. rock is broken into smaller fragments
D. carbon dioxide enters plants, reacts with water in the presence of sunlight to produce carbohydrates and oxygen
E. ammonium is converted into nitrate
F. plants and animals release CO2 back into atmosphere by converting carbs and oxygen into carbon dioxide and water.
G. soil particles + decaying OM accumulate in layers on ground or at the
bottom of large bodies of water
Learning Check!

3. Page 91 Textbook Questions 1-12
1. (a) Abiotic components: atmosphere, land, oceans, and marine and sedimentary rock. (b) The biotic components: producers, consumers, and decomposers. (c) Thicker arrows = movement of more nutrients. (d) Nutrients leave stores in rock by mechanical (physical) weathering and chemical weathering. 4 marks

4. Page 91 Textbook Questions 1-12
2. (a) Carbon is important to living organisms as it makes up DNA, carbohydrates, and proteins. (b) Nitrogen is important to living organisms as it makes up proteins and DNA. (c) Phosphorus is important to living organisms as it is found in the molecule that carries energy to plant/ animal cells. It aids in plant development and bone development in animals. 3 marks

5. Page 91 Textbook Questions 1-12
3. (a) Carbon is stored in the biosphere in plants, animals, in atm. as carbon dioxide, in dissolved form in the upper layers of the ocean, and in long-term stores in sedimentary rock.
(b) Nitrogen is stored in the biosphere as nitrogen gas in the atmosphere, in the ocean, and in land plants and animals.
(c) Phosphorus is stored in the biosphere as phosphate in rock and in ocean floor sediments.
3 marks

6. Page 91 Textbook Questions 1-12
4. Carbon is stored in the ocean as carbonates in marine organism shells and shell sediments on the ocean floor. This sediment eventually forms limestone. 1 mark 5. 3 marks (a) Human activities that have influenced the carbon cycle include transportation, land clearing, agriculture, urban expansion, burning fossil fuels, and clearing land for agriculture and buildings.

7. 5. (b) Human activities have influenced the nitrogen cycle when nitrogen is added to the atmosphere by fossil fuel burning, clearing forests and grasslands, and the use of chemical fertilizers. (c) Human activities that have influenced the phosphorus cycle include the use of chemical fertilizers and detergents that contain phosphates. 6. Geological uplift contributes to the phosphorus cycle as uplift exposes rock that then undergoes weathering. 1 mark 7. (a) Rapidly; (b) Very slowly; (c) Very slowly; (d) Rapidly 4 marks 8. Leaching is the removal by water of substances that have dissolved in moist soil. 1 mark

8. 9. Three ways plants influence the cycling of nutrients are through photosynthesis where carbon is stored and then released in cellular respiration, through nitrogen and phosphorus storage in plants cells, and by uptake of nutrients
into animals. 3 marks
10. (a) iii; (b) ii; (c) I 3 marks
11. Rhizobium lives in the root nodules and supplies the host plant with nitrogen in the form of ammonium. The plant supplies sugar for the bacteria. 2 marks
12. Lightning fixes nitrogen gas and converts it to nitrates and other nitrogen-containing compounds. These compounds fall in acid rain. 1 mark

9. Today! bioaccumulation biomagnification PCB’s POP’s Heavy Metals
Bioremediation

10. 2.3 Effects of Bioaccumulation on Ecosystems
Bioaccumulation: gradual build-up of chemicals in organisms.
Many harmful chemicals can’t decompose naturally
If eaten/absorbed may get ‘stuck’ in body fat
keystone species suffer bioaccumulations, can affect every other organism in its food chain

11. Amphibians
Sensitive to chemical changes  good indicators of environmental health
Many amphibian populations declined since 1980’s
Birth deformities
Theorists think drought,
incr. UV rays, pollution,
habitat loss, parasites,
diseases

12. Biomagnification
Pollutants get more concentrated at higher trophic levels
Bioaccumulating pollutants usually stored in fat
Consumer in next trophic level eats organism w/ bioaccumulated chemicals, receives huge dose of chemicals
2 minutes video

13. BC orcas bioaccumulate PCBs.
PCBs used for industrial/electrical applications in mid 1900’s.
banned 1977 because of fears of environmental impact.
bioaccumulate, have a long-half life (break down very slowly).
will affect reproductive
cycles of Orcas until 2030
or longer

14. Persistent Organic Pollutants
POPs contain carbon, like all organic compounds, and remain in water and soil for many years.
Many POPs are insecticides, used to control pest populations.

15. Persistent Organic Pollutant Example
DDT (dichlorodiphenyl trichloroethane) - introduced in 1941 to control mosquito populations, and is still used in some places in the world. - bioaccumulates and has a long half life. - Even in low levels (5 ppm), DDT in animals can cause nervous, immune and reproductive system disorders Let’s put it everywhere! (5 min) Or not… (3 min)

17. Heavy Metals Metallic elements with high densities
Toxic to organisms at low conc.
Can’t degrade or be destroyed
Some essential to human health in low concentrations
Found in water/air, incorporated in food chains, bioaccumulate and biomagnify.

18. Heavy Metals
1. Lead
found naturally at low levels, but levels have increased.
not considered safe at any level.
Many electronics contain lead,
must be recycled carefully.
Can cause anemia, nervous and
reproductive system damage.

19. Heavy Metals
2. Cadmium:
used to manufacture plastics + nickel-cadmium batteries.
toxic to worms, causes health problems in fish.
Main source of human exposure to cadmium = cigarettes
causes lung diseases, cancer, nervous and immune system damage.

20. Heavy Metals 3. Mercury (Hg): released by fossil fuel burning,
waste incineration, mining,
manufacture of items like batteries.
Coal burning  40% of mercury into atm.
Hg bioaccumulates in brain, heart, kidneys of animals.
Fish bioaccumulate Hg -- poison risk to predators.

21. Mercury in tertiary consumers Mercury in Sharks! (2 min)

22. Reducing Effects of Chemical Pollution
trap chemicals in soil, can’t enter food chains as easily.
Bioremediation : use living organisms to clean-up naturally
- oil industry often use bacteria to “eat” oil spills.
Natural species excellent at bioremediation. (juniper, alfalfa, poplar trees)

23. Bioremediation with hair! (3 min)

24. Today! bioaccumulation biomagnification PCB’s POP’s Heavy Metals
Bioremediation