Biology 1001A Lecture Notes - Lecture 21: Species, Reproductive Isolation, Population Genetics
24 Nov 2017
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Lecture 21 notes: criteria used by the morphological, biological and phylogenetic species concepts to define species. Morphology the idea that all individuals of a species share measurable traits that distinguish them from individuals of other species. (two things look the same probably belong to the same species) The biological species concept defines species in terms of population genetics and evolutionary theory. Genetic cohesiveness of species: populations of the same species experience gene flow, which mixes their genetic material. Thus, we can think of a species as one large gene pool, which may be subdivided into local populations. Because populations of different species are reproductively isolated, they cannot exchange genetic information. In fact, the process of speciation is frequently defined as the evolution of reproductive isolation between populations. Phylogenetic species concept is that seeks to explain species as the smallest collective population that can be united by shared derived characters: weaknesses/limitations of these different species concepts.
