Biology 1001A Lecture Notes - Lecture 20: Species Problem, Phylogenetic Tree, Reproductive Isolation
16 Aug 2017
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Any one definition of species in biology is not uniformly used by all biologists. The taxonomic hierarchy: comprises a nested series of formal categories: domain, kingdom, phylum, class, order, family, genus, species, and subspecies, the organisms included within any category of the taxonomic hierarchy comprise a taxon. Species concepts: the concept of species is based on our observations that earth"s biological diversity is packaged in discrete, recognizable units, and not as a continuum of forms grading into one another. None are easily applicable to all living organisms. Criteria used by the morphological, biological and phylogenetic species concepts to define species. If the members of two populations interbreed and produce fertile offspring under natural conditions, they belong to the same species; their fertile offspring will, in turn, produce the next generation of that species. Clicker question: baltimore and bullock"s orioles look different, and d onot form monophyletic calde. Distinguish between pre-zygotic and post-zygotic isolating mechanisms and recognize examples of each.
