NAME ____________________________                                                  BIO 567                                                                       EXAM III                                Spring 2000

Give a definition of the following terms that includes their relevance to physiological ecology.  (20 points)

-- pheromone


-- allelopathy


-- viper “pits”


-- Rhizobia


-- Rhizosphere –


-- Mycorrhizae


-- “Growth/Differentiation balance hypothesis”


-- electoreception


-- electro-defense


-- electro-communication

2.  Select ONE variety of  “chromatophore” cell, and address the following:  (10 points)


what are the possible ecological functions of these cells (a list will suffice)?



how does the cell change it appearance (what’s happening inside the cell)?



how is the cell controlled (what possible signals is it receiving)?





3.  Many predators must find prey in habitats where vision is poor to non-existent.  Select one such example and provide the following information.  You can have a real predator in mind or a realistic hypothetical one.  (5 points)

             Habitat             ____________________________

             Sensory system used to locate prey            _____________________________

             Special adaptations to make this an effective predator



4.  Why is the symbiotic association between rhizobia and plant roots not more common (i.e., why does it not solve the almost perennial problem of nitrogen limitation in the plant kingdom)? (5)







5.  A farmer wants to grow alfalfa (a N-fixing plant) in a field that has been fallow, and asks you for a recommendation about fertilizing the field with ammonium nitrate. Based on your knowledge of the effects of fertilizing N-fixing plants with nitrogen or with phosphorous, what would you recommend to the farmer with respect to nitrogen fertilization, and with respect to fertilizing the field in general? (5)





6.  A farmer wants to grow wheat in a field that has been inoculated with mycorrhizal fungi. What would the effect of phosphorous additions to the soil have on the colonization of wheat roots by the mycorrhizae (5)?






7.  Explain in detail why the world is “green” (that is, why don’t herbivores consume, in general, more that 10% of above ground net primary productivity).

Include, for example, why it does not have to be that way, plant chemistry, and the unpredictability of plants as food (with respect to both quantity and quality). (Hint: I do not just want a laundry list of ‘facts’. I want a well thought out, carefully considered and written answer that reflects that you absorbed something from the 3 hours of lecture and discussion) (10 points)







8.  Give (w/ some explanation) ONE example of how herbivores can bypass (or otherwise avoid negative consequences) of plant defensive compounds.  This can be a real example or a hypothetical one that is realistic.  (5 points).








9.  Select a parasite and give possible adaptations that it might have to be a good one.  Speculate on possible adaptations that the host might evolve to reduce the predator load that it has. (10 points)






10.  Given: You note a situation in nature where you have observational evidence that one (or more) plant species (Species X) does not appear to grow very well in the vicinity of another plant (Species Z).  You “think” it might be an allelopathic phenomenon.  Comment on each of the following.  (15 points)


A)    If you were to try and isolate a chemical cause of this interference, what general types of biochemicals might you be looking for?  Be as specific, either by class or compound, as you desire to be, but also indicate what wrong assumption might be made in the way I have asked the question.




B) What factors/conditions can influence the relative amount/presence of allelochemicals you commented on in the question above?




C) If the assumption in your observation is that allelochemicals are influencing the growth of Species X (the receiving species), suggest some possible physiological effects on the receiving species.  (i.e., What are some possible mechanisms of action?)




D) Although it is very difficult to separate competition from allelopathy, investigations are often designed to attempt this goal.  Keep it simple, but suggest a experimental design that you might use in the situation of species X and species Z that would give some evidence that allelopathy was involved.

11.  According to the following abstract, what is novel about this finding?  Is this a releaser of primer pheromone?  What are some differences b/w these two categories of pheromonal actions? (5 points)



12.  According to this article, what unique ability does this animal have?  What is the animal’s position in the ecological community [HINT:  think about herbivores and plants].  How do you suppose the animal can do this (cellular/biochemical explanation). (5 points)