EvolutionExam - Chapter 21: A cline is a: a.) a species...

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Chapter 21: A cline is a: a.) a species that can exchange genetic material directly, but gene flow between the distant populations occurs only through intermediate populations b.) a pattern of smooth variation over along a geographical gradient c.) isolation caused by living in different habitats d.) a local variant of a species Speciation depends on geography. List and describe the three types of speciation that relate the geography. How are they different from each other? Three types of speciation are allopatric speciation, parapatric speciation and sympatric speciation. Allopatric speciation occurs when populations become geographically separated due to a barrier or when a small portion of the original population gets separated. Allopatric speciation occurs in two stages. First, the two populations become physically (that is, geographically) separated. Second, genetic differences accumulate and the new species is no longer reproductively compatible with the original species. Parapatric speciation occurs between adjacent populations, because of discontinuous environmental conditions. Even though organisms from both sides of the environment mate with each other, different alleles might be more beneficial on one side thereby limiting gene flow. The hybrid offspring (the result of mating between organisms of both sides) will generally have low relative fitness in parapatric speciation. Sympatric speciation occurs when there is no geographic/environmental isolation, and reproductive isolation evolves between distinct subgroups in one population. Sympatric speciation can be attributed to polyploidy, habitat isolation, behavioral isolation, temporal isolation and reproductive isolation. Chapter 23: When a species is arranged in a phylogeny that requires a small number of evolutionary changes D) Parsimony Why are morphological traits often helpful in tracing the evolutionary relationships within a
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This note was uploaded on 01/18/2012 for the course ECON 101 taught by Professor Sei during the Spring '11 term at American Academy of Art.

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EvolutionExam - Chapter 21: A cline is a: a.) a species...

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