BIOL359 Chapter Notes -Reproductive Isolation, Monophyly, Phenotype
11 Jan 2015
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Difficult to define what a species is, no one knows how many species are alive today. Cryptic species = species that are indistinguishable morphologically, but divergent in songs, calls, odor or other traits. Copopods = nine different samples, sequenced mitochondrial dna, constructed phylogenetic tree, couldn"t mate, based on biological species concept (must be interbreeding population and reproductively isolated), since cant mate, weren"t species. Went on to sequence dna, based on sequence, she constructed phylogeny tree, saw that they were actually related. And some populations from different regions form monophyletic groups. Type specimen = single individual that represents entire species. Phenotypic plasticity morphological variation that does not have a genetic basis. Environmentally induced morphological differences. issues associated with this method. Phylogenetic concept: focuses on identifying species called monophyly. Monophyletic groups are lineages that contain all of the known descendants of a single common ancestor. Showed that populations from different phylogenetic species are unable to produce fertile offspring and are reproductively isolated.
