Chapter 25 – Ecology
Chapter 25
Ecology
Multiple Choice Questions
1. All the living organisms plus the environmental factors present in a given area constitute
2. Which of the following estimates or calculations are made with respect to populations?
Chapter 25 – Ecology
3. In an energy pyramid of an ecosystem ___________________________.
4. Chemicals produced by higher plants that kill or inhibit disease fungi or bacteria are known
as ________________.
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5. The factors that allow organisms to grow, compete, reproduce, and perpetuate the species
in a particular area are part of a field of inquiry called
6. When a grass plant is eaten by an herbivore, which in turn is eaten by a carnivore, this is an
example of a
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7. The __________ or living component of any environment includes all individuals of each
species that interact in that habitat.
8. Components of the abiotic environment include ____________________________.
Chapter 25 – Ecology
9. A _______________ is a group of individuals of the same species, occupying the same
region and potentially interacting with each other.
10. Features of plants and animals that allow them to survive and reproduce in their
environment are considered ________________. One example of this is CAM photosynthesis
in desert plants.
Chapter 25 – Ecology
11. The foremost ecosystem decomposers are
12. More than 100 years ago Thomas Belt called attention to the symbiotic association
between Acacia shrubs and ants. Acacia encouraged the association by providing food for the
ants and a home in ______________________________.
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13. Trophic efficiency
14. In exchange for food and housing, the ants in the ant-Acacia symbiotic association
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15. Which series illustrates the correct hierarchy in relationship to each other in the series?
16. On average, plants capture and convert approximately ______ of the energy in sunlight
reaching the earth’s surface.
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17. Movement of materials through any community can be tracked by developing a/an
_________ for that community.
18. The reproductive strategy of any plant species is regarded as ____________________.
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19. Weedy plant species are ______________________.
20. Nitrogen fixation refers to ______________________.
21. When nitrogen from the air is converted to ammonia or other nitrogenous compounds by
microorganisms, it is said to be
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22. Microorganisms that gain access to various plants, particularly legumes, usually do so
through or as a result of which of the following?
23. Loss of nitrogen from the soil occurs as a result of which of the following?
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24. Which of the following is the term used for bacteria that use nitrates instead of oxygen in
their respiration?
25. As much as 90% or more of the carbon dioxide needed throughout the earth for
photosynthesis is produced by
26. Loss of nitrogen from the soil due to a fire may be offset by which of the following?
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27. Carbon dioxide comprises approximately what percentage of the atmosphere?
28. Carbon dioxide is important to plants because it acts as the carbon source in which
process?
29. Plants obtain their nitrogen supply directly from
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30. The structure produced when nitrogen-fixing bacteria infect legume plants and forms a
symbiotic relationship is called a(an) _____.
31. Which of the following is an example of secondary succession?
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32. _________________ and _________________ are the two common gases that lessen
re-radiation of heat back into the space and, hence, contribute to increasing temperatures on
Earth.
33. Events predicted to occur with increasing global temperatures include
_________________.
Chapter 25 – Ecology
True / False Questions
34. A producer is an organism that carries on photosynthesis.
35. The foremost decomposers in ecosystems are the roots of plants.
36. Energy is normally completely recycled in an ecosystem.
Chapter 25 – Ecology
37. The total mass of consumers is largely determined by the total mass of food made
available by the producers.
38. Phenology refers to the timing of developmental events, such as germination, flowering
and seed production, in the life cycle of a plant.
39. Climax vegetation always consists of some type of trees.
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40. Fires benefit both grassland and forest vegetation by converting dead organic materials to
nutrient-rich ash.
41. Hydrophyte plants require running water for pollination.
42. Kudzu, tamarisk, and the agents that cause Dutch Elm disease and American Chestnut
blight are examples of how introduction of foreign species can disrupt natural ecosystems.
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43. Primary succession usually takes place in areas previously covered with vegetation.
44. Eutrophication refers to the process of decay.
45. The majority of chaparral species, both woody and herbaceous, are so adapted to fire that
46. Carbon dioxide is taken up during respiration and the decay process.
Chapter 25 – Ecology
47. Acid deposition lands on plants and lowers the pH of lakes, ponds, and soil. Plants are
harmed when acid falls on them but are not affected by changes in pH of the soil or water in
which they grow.
48. Succession after a disturbance produces exactly the same plant communities as had
existed before the disturbance.
49. Humans have little impact on water, carbon, and nitrogen cycles in the biosphere.