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Unformatted text preview: objective units with definable limits - basic units of evolution . No mistake that the Biological Species concept was advanced by two zoologists who worked with organisms that did not present some of the more obvious problem of plants and bacteria (Nevertheless, there is clear discontinuity in the phenotypes of bacteria). Isolating "Mechanisms" (misleading term: is it a mechanism in that it evolved for the purpose of isolating; or did isolating "mechanisms" evolve in one context and serve to prevent mating on another?). Premating mechanisms prevent interspecific crosses. Temporal or Ecological isolation (don't meet due to different time of emergence or occur in different habitats). Ethological (behavioral) isolation (meet but don't mate) e.g. fireflies. Mechanical isolation (can't transfer sperm, morphological incompatibilities). See table 15.1, pg. 405....
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- Fall '10