ECOLOGY UNIT REVIEW
Name:
1. In what ways can Earth be considered “an island”?
2. What does it mean to manage natural resources in a sustainable way? Give two examples of how
overexploitation of a resource has harmed ecosystems.
3. Explain why Easter Island was considered an “ecological disaster”?
4. Consider the hierarchy of biological organization (shown below) to answer the following:
a)
b)
c)
d)
e)
What is the biosphere? What three physical spheres make up the biosphere?
What is an ecosystem? Distinguish between the terms aquatic and terrestrial.
What is the difference between a biotic and abiotic component of an ecosystem?
Distinguish between the terms population and community.
What is an ecological niche?
5. Explain the terms evaporation, condensation, precipitation, and run-off, as they relate to the water cycle.
You can draw a picture if that is easier.
6. What is the word equation for a) photosynthesis? b) cellular respiration? Why are they said to be
complementary processes?
7. Distinguish between the terms carbon source and carbon sink. Give an example of a human activity that
affects the carbon cycle.
8. What is the greenhouse effect? How have humans affected this natural process? Explain how these terms
relate to global warming and climate change.
9. Explain the terms nitrogen fixation, nitrification, and denitrification as they relate to the nitrogen cycle.
10. What is a fertilizer? What is the risk of using fertilizers?
11. What is a pesticide? What are some of the risks of using pesticides? Explain the terms bioaccumulation
and bioamplification.
12. Consider the following food chain to complete the table below.
Grain

organism
grasshopper
grain

sparrow

grasshopper
Snake

sparrow
wolf
snake
wolf
trophic level
producer /
consumer
(specify)
herbivore /
(top)
carnivore
13. Why is a producer necessary in all food chains
14. What is the role of a decomposer?
15. How is a food web different from a food chain?
16. What do the arrows in a food chain represent?
17. Approximately how much energy (%) is passed on to the next organism in a food chain? Why is so
little energy passed on to the next level? What happens to the rest of the energy?
18. Using the food chain below, consider the following:
phytoplankton → zooplankton → krill → cod → seal → polar bear
a) If each phytoplankton has only one atom of mercury in it, and every zooplankton must consume
600 phytoplankton in a year to survive, how many atoms of mercury are there in one zooplankton
after a year?
b) If a krill must consume 300 zooplankton in a year to survive, how many atoms of mercury are
there in one krill after a year?
c) If a cod must consume 100 krill in a year to survive, how many atoms of mercury are there in one
cod fish after a year?
d) If a seal must consumer 75 cod in a year to survive, how many atoms of mercury are there in one
seal after a year?
e) If a polar bear must consume 10 seals in a year to survive, how many atoms of mercury are there
in one polar bear after a year?
f) Assume that a concentration of 1200 000 000 atoms of mercury would be fatal to a polar bear.
What would be the fate of the polar bear (from the food chain above)?
19. Density-independent (abiotic) limiting factors determine where a particular species is able to live. Give
some examples of abiotic factors and explain how they can limit population size.
20. Density-dependent (biotic) factors determine how easily a species can survive in an ecosystem. Distinguish
between the following different types of interactions between organisms: intraspecific competition,
interspecific competition, predation, mutualism, commensalism and parasitism.
21. Distinguish between the terms realized (actual) niche and fundamental (potential) niche. How does the
presence of other species determine the realized niche?
22. Define carrying capacity. How do human actions affect the carrying capacity of an ecosystem?
23. Explain the trends in population size in the graph below:
24. Humans are the only species to have expanded their ecological niche. Explain what this means, and how
this was possible.
25. Define ecological footprint. Propose two reasons that the average ecological footprint of North Americans
is greater than that of Africans?
26. What is biodiversity, and what are the three ways that it can be described? Explain the connection
between biodiversity and the health of an ecosystem.
27. What is a species at risk? Distinguish between the following different classifications of species at risk:
extinct, extirpated, endangered, threatened, and special concern.
28. What is an invasive species? What are some consequences of introducing an invasive species to an
ecosystem? What are the three approaches to controlling an invasive species?
29. Other than the introduction of invasive species, what are the other two major ways that humans are contributing to the
loss of biodiversity?
30. What is environmental stewardship?
31. Distinguish between the following methods of conservation: reforestation,
wetland restoration, bioremediation, bioaugmentation
32. Distinguish between the following terms, and provide an example of each:
dominant species, keystone species, ecosystem engineers, and charismatic
species.