Evidence for Evolution:

• principle of uniformitarianism
• scientific evidence for evolution:
• observation of current evolution.  Ex: peppered moth
• artificial selection.  Ex: development of dog breeds
• ring species. Ex: salamanders around central valley of California
• hierarchical pattern of homology.  Ex: characteristics of vertebrates:
• 
• fossils.  Ex: bones of horse feet

• prezygotic isolation
• postzygotic isolation

• barriers to gene flow
• evolution of reproductive isolation

Phylogeny

• tree representations speciation history (evolutionary relationships)
• 
• evidence:
• fossils
• homology (this is studied in more detail in lab!)

 QUESTIONS:
1.  The principle that states that if a process can be observed now, it is reasonable to assume that it also occurred under similar conditions in the past, is called ____________________.  How is this principle applied to evolutionary biology?
2.  A species with a circular geographical distribution within which neighboring populations can reproduce, except at one point, is called a _____________________.  The observation that such species exist provides evidence that (choose the one for which it provides the most direct evidence):
  a. all species have evolved from one ancestral species
  b. it is possible for speciation to occur in nature
3.  Explain what it means to say the pattern of homology we observe in organisms is hierarchical.  Give an example to illustrate your explanation.   The hierarchical pattern of homology provides evidence that (choose the one for which it provides the most direct evidence):
  a.  different species have evolved from common ancestral species
  b.  the genes present in populations change over time
4.  Describe how fossils of horse's legs show evolutionary change.
5.  How is the process through which humans have created different breeds of domesticated animals similar to evolution?  To which form of evolution is it most similar?
6. What is reproductive isolation?  The two main ways in which species can be reproductively isolated from each other are ___________________ and _____________________.
7.  Is speciation caused by some of the same kinds of microevolution that result in changes within populations, or is some different form of evolution required to lead to speciation?
8.  Two main forms of evolution that result in speciation are _________________ and ___________________.  Why do these forms of evolution lead to speciation? In contrast, one form of evolution tends to prevent speciation from occurring; this is _______________________.  Why does this form of evolution tend to prevent speciation?
9.  What does "allopatric" mean?
10.  What are some kinds of barrier that could isolate populations from each other and lead to allopatric speciation?
11.  Suppose A, B, and C are three different species.  Which of the following phylogenetic trees say the same thing about evolutionary relationships?  Which say different things from each other?

12.  What two kinds of data provide evidence for phylogenetic relationships among species?
13.  On the following phylogeny identify:
 o the ancestor to the butterfly and skipper but not the moth
 o all species that are just as closely related to the bee as the moth is to the bee
 o the closest relative or relatives of the bee
 o all species that are just as closely related to the moth as the grasshopper is to the moth
 o the point at which an ancestor to the ant speciated from an ancestor to the skipper
 o the species that is most distantly related to the ant