BISC208 Chapter Notes - Chapter 24: Sympatric Speciation, Species Complex, Species
19 Jun 2017
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Document Summary
Speciation results from genetic isolation followed by genetic divergence: can result abruptly or gradually. The three most common ways to determine species: biological species concept, morphospecies concept, phylogentic species concept. Logic behind morphospecies concept is that distinguishing features are most likely to arise if populations are independent and isolated from gene flow: equally applicable to sexual, asexual or fossil species, disadvantages. May lead to naming of two or more species wen there is only one polymorphic species with differing phenotypes. The morphological features used to distinguish species are subjective. Synapomorphies are homologous traits that can be identified at the genetic, developmental or structural level. Phylogenetic species concept has two distinct advantages: can be applied to any population, is logical because different have different synophmorphies only if they are isolated from gene flow and evolved independently, disadvantage. Carefully estimated phylogenies are available only for a tiny subset of populations on the tree of life.
