Animal Ecology (Zoology 441)
Practice questions ? physiological ecology, niches, resources
 

1. What is Liebig's Law of the Minimum?  What is a limiting factor?  How is the idea of limiting factors related to tolerance theory?
2. Consider the tolerance of an organism to two abiotic factors.  Draw a graph that would represent tolerances to these factors interacting with one another, and a graph that would represent tolerances to these factors NOT interacting with one another.
3. Tolerance curves are usually developed to describe how an animal survives in different conditions.  With regard to conditions in the natural world where populations can occur, what information in addition to survival are ecologists really interested in?  Why don't we get that information, rather than just survival?
4. An aquatic organism is said to be "stenohaline".  "haline" refers to salinity (salt concentration.)  What can you say about the range of salinities that this organism can tolerate?
5. Draw a graph that illustrates the difference between an eurytopic organism and a stenotopic organism.
6. Define "conformer" and "regulator" and draw a graph that represents the two strategies.  Discuss the costs and benefits of being a conformer vs. being a regulator.  Give examples of animals that are neither completely conformers nor completely regulators and consider how this intermediate situation may be adaptive, in terms of the costs and benefits you already discussed.  Illustrate your example with animals that are neither complete conformers nor complete regulators with regard to body temperature.
7. A water shrew, which is an endothermic homeotherm, and a salamander, which is an ectothermic poikilotherm, live in the same pond and have the same body mass.  During the year, the pond shows seasonal changes in temperature.  Contrast the costs imposed by the changing temperature in the environment to the shrew and the salamander.
8. What is acclimation?  How do the mechanisms of acclimation compare between organisms that are regulators for some factor and organisms that are conformers for that factor?
9. In a population of fish (poikilotherms) that occur in a pond that shows strong seasonal changes in temperature, the fish have high levels of activity throughout the year.  You hypothesize that the fish are acclimating.  Why does the situation you have observed suggest acclimation?  Design an experiment that would allow you to test your hypothesis of acclimation.  Assume the fish can be kept in laboratory conditions.
10. Distinguish between homeothermy, poikilothermy, endothermy, and ectothermy.
11. Explain what conduction, convection, radiation, and evaporation are and how they are involved in heat loss/gain in animals.
12. Describe ways in which an ectotherm can regulate its body temperature; refer to the main physical processes through which an animal can gain and lose heat in your answer, and come up with a way an ectotherm can regulate its body temperature that involves each of these main physical processes.
13. What hypotheses are tested, using what predictions, in the study of temperature preference, habitat, and enzyme activity in the four lizard species decribed in lecture?
14. Explain why body size needs to be considered when studying the energetics of thermoregulation.  Consider the geometry of increasing body size and how it affects heat storage and heat loss/gain
15. Draw a graph of the metabolic rate of an endotherm over a range of environmental temperatures.  Be sure to label the axes.  What happens to body temperature over this range of conditions?
16. Why does the metabolic rate of an endotherm increase in cold conditions? Why does the metabolic rate of an endotherm also increase slightly in very hot environmental conditions?
17. Discuss different animal strategies for dealing with hot and cold temperatures.  Which involve regulating?  Which involve conforming?  Which involve animals that usually regulate for body temperature conforming temporarily?  What is the advantage to doing this?
18. Compare an endotherm with large body size to one with small body size.  Which one would you expect to spend a higher amount of its energy per body mass thermoregulating?  Why?
19. Lizards are homeothermic ectotherms.  Explain what this means.  Consider two lizard species living in the desert.  Both are active during the hot part of the day.  One is twice as big as the other.  Why will this size difference affect they way they lose heat?
20. Give two ways in which "ecological niche" has been defined.  What is the distinction between these?
21. Can we expect to determine the ecological niche of a species?  If so, how?  Can we more readily determine the realized or the fundamental niche?  If one of these can't clearly be determined, what makes it a useful concept?
22. Distinguish between the fundamental and realized niches.  Which is expected to be broader?  Why?
23. What is meant by a "niche axis"?
24. Give examples of the main resources required by animals.  Which would you expect to be limiting factors?
25. What does it mean to say that some resources are substitutable while others are essential?  Relate these concepts to the concepts of 'specialist' and 'generalist'
26. What is niche partitioning?  Relate this concept to the Hutchinsonian niche.  Would we expect to see niche partitioning between potentially competition species that occur in the same area or that occur in different areas?
27. Among birds and mammals, small bodied species require higher food intake per gram of body weight than large bodied species.  Why does body size affect resource requirements in this way?
28. Compare how food resources are used by herbivores versus carnivores.