Terms to know:  speciation, extinction, key innovation, species selection, adaptive radiation, mass extinction

Questions:

1. Species selection occurs because of differences in the rates of two main processes; what are these two processes?
2.  Within the kingdom Plantae (the plants), most species produce flowers.  Give two explanations for the abundance of species that produce flowers that are based on species selection, one based on each of the two main processes that result in species selection.  Now can you give a plausible evolutionary explanation for this that is NOT based on species selection?
3. Within the mammals, two orders contain most of the mammalian species: the rodents and the bats.  Give hypotheses that could explain the large number of bat species and of rodent species based on key characteristics.  Give an alternative hypothesis based on species selection that could explain the abundance of rodents and bats.
4. The West Indies, the Hawaiian islands, and the Galapagos archipelago are three different groups of islands.  Within each group of islands, the following kinds of species are observed:   a variety of species occur that are different in structure from each other, but are clearly each others' closest relatives.   This pattern is thought to result from adaptive radiation. Why does adaptive radiation result in this kind of pattern?
5. Describe three general kinds of circumstance in which adaptive radiation is likely to occur.
6. What is a mass extinction?  Do you expect adaptive radiation to be more common before, during, or after a mass extinction?  Why?
7. What is meant by a "key innovation"?  Give examples of traits that have been proposed to be key innovations.  What is the result of a key innovation?  Do traits initially evolve within species because they are key innovations?  Why/why not?
8. Briefly describe how we would test for key innovations by using a phylogenetic approach to test for their predicted results.
9. It has been proposed that jaw structure in cichlid fish is a key innovation since it allows the jaw to be modified to feed in a variety of different ways.  A distantly related fish group, the Beloniformes, has evolved the same jaw structure as cichlids through convergent evolution.  Draw phylogenies of cichlids and their closest relatives lacking this jaw structure, and of the Beloniformes and their closest relatives lacking this jaw structure, that would support the hypothesis that this jaw structure is a key innovation.  Draw phylogenies that would not support this hypothesis.  For each phylogeny, use as many species is each group (cichlids, beloniforms, and their relatives) as is necessary to demonstrate whether or not the trait could be a key innovation.
10. It is hypothesized that the evolution of venom in snakes acted as a key innovation.  Which of the following phylogenies best supports this hypothesis? Explain why.  In your answer, fully explain what a key innovation is, what results from a key innovation, why this results, and why the pattern shown in the phylogeny best supports the hypothesis. 
11. On the following phylogeny, the letters indicate the points at which each of four characters originated.  Which character (w, x, y, or z) is most likely to be a key innovation?  Clearly explain why; in your answer, explain what a key innovation is, what results after the evolution of a key innovation, and why the character you selected best shows this predicted result.