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Species and Speciation (Origin and Fate of Species (Speciation refers to…
Species and Speciation
Species, Origin & Fate of Species, Misconceptions About Evolution, and Taxonomy
In evolutionary contexts, researchers often use the concept of biological species. This is defined as:•in nature, two organisms cannot interbreed and/or cannot produce viable offspring; mutually exclusive regarding breeding•for example, interbreeding between a horse & a donkey produces the sterile mule
subspecies is used to divide a species into two or more divisions that have little to no gene flow between them
in practical terms, applying the conceptof biological species can be messy.
super difficulty when we look at the fossil record, thus the concept of paleospecies; defined on basis of:•form•time period•geographical area•habitats
The origin & evolution of species is called macroevolution, which is the result of long-term patterns of evolution. (think about how this contrasts with microevolution)
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How rapid is the pace of evolution of species?:phyletic gradualism (Darwinian evolution): small changes accumulate slowly over long periods of time•punctuated equilibrium: rapid biological changes followed by long periods of nearly no change
adaptive radiation periods when speciation results in several new, but closely related, species that are more or less contemporary in time
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extinction of species is common in macroevolution(more than 99% of all species that ever existed have become extinct)
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