BIO152H5 Lecture Notes - Lecture 20: Sympatric Speciation, Allopatric Speciation, Chromosome

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13 Feb 2017

Document Summary

Process by which one species into 2/more species fascinated darwin because it is responsible for the tremendous diversity of life, repeatedly yielding new species that differ from existing ones. Speciation does not only explain difference between species, but also similarities between them. When one species splits into two, the species that result shar many characteristics because they descended from one common ancestral species. Example: dna of flightless cormorant is similar to flying cormorant found in. Suggests that flightless cormorant may have originated from common ancestor that migrated from the mainland to galapagos. Macroevolution origin of new groups of organisms. Microevolution mechanisms mutation, gene flow, genetic. Macroevolution mechanisms origin of new group of organisms, mammals/plants, through a series of speciation events. 4 common approaches to identifying species: biological species concept, morphospecies concept, ecological species concept, phylogenetic species concept. Barriers can be classified as to whether they contribute before or after fertilization: prezygotic ( before the zygote ) blocks fertilization from occurring.