V. Values discussion
Answer the following questions. Then discuss your answers with your classmates.
1. What are the organic material and oxygen produced by?
a. heterotrophs b. green plants с detritus feeders d. other
2. What do consumers and other heterotrophs require?
a. green plants b. the food с oxygen d. other
3. What is the first basic principle of ecosystem sustainability?
a. Ecosystems dispose of wastes.
b. Ecosystems replenish nutrients by recycling all elements.
с Atoms are neither created nor destroyed, nor converted one
into another, d. other 4.1s this principle in harmony with the Law of Conservation of Matter? a. no b. yes с I don't know. d. other
5. Where may carbon dioxide molecule be found?
a. present in soil с dissolved in water
b. present in the air d. other
6. How do carbon atoms from carbon dioxide become the carbon atoms of all the organic molecules?
a. through all the organisms in the ecosystem
b. through further metabolism с through photosynthesis
d. other
7. When are the carbon atoms released back to the environment in molecules of carbon dioxide?
a. When the consumer will break down the organic molecule in cell respiration.
b. When completing one cycle.
с When burning organic material, d. other
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8. Where does phosphorus exist as inorganic phosphate ion?
a. in water с in various rock
b. in soil d. other
9. How do plants absorb phosphate?
a. from the soil с from water solution
b. from air d. other
10. What is an important difference between the carbon cycle and the phosphorus cycle?
a. When carbon dioxide is released, it will mix into the air. !
b. When carbon dioxide is released, it will maintain the concen tration of carbon dioxide in the air. . 'I
с The phosphorus cycle does not have a gas phase, d. other
11. How does phosphate make its way into waterways?
a. directly by way of runoff from agricultural croplands
b. by mining phosphate rock
с indirectly by way of discharge of sewage effluents d. other
12. Why is the nitrogen cycle more complex than the carbon and phos phorus cycles? s
a. It has a mineral phase.
b. It has a gas phase. - с It has both a gas phase and a mineral phase.
d. other
13. Where is the main "reservoir" of nitrogen?
a. in the soil b. in water с in the air d. other
14. How can plants utilize nitrogen gas?
a. as ammonium ion с as nitrate ion
b. directly from the air d. other .
15. What process is called biological nitrogen fixation?
a. symbiosis of the legume and the bacteria *
b. symbiosis of nodules on roots of legumes and the bacteria с conversion of nitrogen gas to the ammonium form
d. other
16. What is atmospheric nitrogen fixation?
a. Animals break down proteins and other organic compounds.
b. Nitrogen is excreted, generally in the ammonium ion form.
gcosystems: How They Work 63
c. Nitrogen gas is converted to the ammonium form by discharg es of lightning.
d. other
17. What do all natural ecosystems depend on?
a. legumes with their symbiotic bacteria
b. nitrogen-fixing organisms с a huge diversity of plants d. other
18. What plants are the first to recolonize a burned-over area?
a. desert shrubs с legumes
b. clovers d. other
19. How do you feel about the nitrogen cycle in aquatic ecosystems?
a. It differs from terrestrial systems.
b. It is similar to terrestrial ecosystems.
с It is the same as in terrestrial ecosystems, d. other
20. How have humans been able to bypass the necessity for legumes when nonlegume crops are being grown?
a. They produce ammonium and nitrate compounds.
b. They alternate legumes with nonlegume crops, с They fix nitrogen in chemical factories.
d. other '••■■