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12 Cards in this Set
- Front
- Back
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True or False? Synapomorphies identify monophyletic groups? |
Ture |
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What is good evidence of homology and not homoplasy in a phylogenetic tree? |
Traits occur in many intervening lineages on the tree of life.
Why? -If intervening lineages also share the trait, it was most likely inherited from the same common ancestor. |
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True or false? Convergent evolution is said to have occurred if the mouse species on two islands with similar habitats are found to have similar characteristics even though they originated from different species that did not have these characteristics. |
True
Convergent evolution occurs when selective pressures produced by similar conditions (such as habitat) favor the evolution of similar solutions. |
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What is adaptive radiation? |
An adaptive radiation occurs when a single lineage produces many ecologically diverse descendant species in a relatively short period of time.
It is an increase in species number, due to the advantages of having different populations evolve to occupy different available niches. |
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How can mass extinction events be distinguished from background extinctions? |
A mass extinction occurs when at least 60 percent of species are wiped out within 1 million years. |
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Why do mass extinctions wipe out species more or less randomly? |
They are caused by exceptionally harsh, short-term conditions. Because they are caused by extraordinary, sudden, and temporary changes in the environment, mass extinctions are largely random with respect to the fitness of individuals under normal conditions. |
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What are Synapomorphies? |
-Traits found in two or more taxa that are present in their most recent common ancestor but not more distant ancestors |
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What is Parsimony? |
Principle of logic and states that the most likely expansion or pattern is the one that implies the least amount of change |
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When does Homology occur? |
When traits are similar due to shared ancestry |
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When does Homoplasy occur? |
When traits are similar for reasons other than common ancestry |
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When does Convergent Evolution occur? |
When natural selection favors similar solutions to similar environmental pressures.
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What are SINEs? |
Short Interspersed Nuclear Elements
Parasitic DNA sequences which occasionally insert themselves into mammalian genomes |
