Biology 156 2 Apr 2001 Evolutionary Ecology Bob Podolsky

Week 12. Coevolution Study guide

After the module on coevolution, you should be able to:

Lecture 12.1. Specificity in mutualisms: 1. Explain why Darwin claimed that "natural selection cannot produce a structure in one organism that is exclusively for the good of another species." 2. Distinguish between the concepts of "diffuse" and "pairwise" coevolution, and give hypothetical examples of each. 3. Give an argument for whether or not Seeley's crab/snail interaction is likely to lead to a coevolutionary relationship. 4. Provide an argument for why there are relatively few examples of specific coevolution between species pairs 5. Describe the initial observations concerning ant/plant interactions that led Davidson et al. to examine costs and benefits to the two types of interactors 6. Describe the experiments and controls that Davidson et al. used to distinguish between two hypotheses for the evolution of "pruning" behavior by ant species 7. Describe a particular observation suggesting that pruning was likely driven by selfish interests of ants 8. Explain the results of a survey of ant/plant associations which supported experimental observations of the consequences of pruning 9. Describe the basic life cycle and interaction between yucca plants and a pollinating species of yucca moth 10. Explain the basic reproductive tradeoff that demonstrates a conflict of interest between the two mutualists 11. Explain why intermediate levels of moth oviposition are best for the plant, but not best for the moth 12. Explain Pellmyr and Huth's hypothesis for how the plant appears to exert selection on the moth to maintain intermediate levels of oviposition 13. Describe their experimental results suggesting that plants must have some way of detecting the degree of moth oviposition 14. Explain why their data rule out the hypothesis that seed destruction leads to selective fruit abortion 15. Explain what their phylogenetic data across groups of pollinating moths suggest about the number of times mutualism (active pollination) has evolved 16. Explain how detailed phylogenetic data are consistent with the idea that mutualism and parasitism may be in a dynamic flux Lecture 12.2. Evolution of virulence, cospeciation

17. Describe the original conditions of the experiment by Jeon with amoebae and bacteria 18. Explain details of experiments they used to examine responses of host and symbiont to one another after several years of association 19. Use their experimental results, or similar hypothetical results, to support or refute the hypothesis that coevolution had occurred between the symbionts 20. Explain why their conclusions are relevant to the evolution of endosymbiosis 21. Describe the basic life cycle of the fig wasp in relation to the development of fig syconia 22. Give a definition of virulence and explain whether it is a property of the host or the parasite 23. Explain the likely causal relationship between reproductive rate of the parasite and virulence 24. Explain why the mechanism underlying virulence sets up a tradeoff between parasite replication and transmission to new hosts 25. Describe the difference between horizontal and vertical transmission of the parasite, and why these two modes would influence the evolution of virulence 26. Explain Herre's prediction concerning the evolution of virulence in nematode parasites of fig wasps, and the relationship of virulence to the ecological conditions of foundress number 27. Describe the nature of the data collected by Herre and whether they supported his predictions 28. Evaluate the statement that parasitism always evolves to more and more benign states 29. Give a definition of cospeciation, and describe its relationship to coevolution 30. Recognize phylogenetic patterns that are consistent with a process of co-speciation, and those that are not 31. Give the basic biology of the leaf-cutter ant/fungus association, and why species were predicted to show patterns of cospeciation 32. Describe the results of Hinkle et al., and explain why they support a pattern of cospeciation between ants and fungi 33. Point out patterns in the data of Chapela et al. which indicate that some species of formerly cultivated fungi have "escaped" cultivation by ants, while other species of formerly free- living fungi have apparently been newly captured and cultivated by formerly unassociated ant species