ECOL 335 Lecture Notes - Lecture 4: Pattern Formation, Parthenogenesis, Volvocales
27 Aug 2018
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Document Summary
Groups of actually or potentially interbreeding natural populations, which are reproductively isolated from other such groups. Find the smallest monophyletic group = species. According to mayr"s definition, speciation occurs when reproductive isolation evolves between two populations of the same (ancestral) species. Two populations form different species when they are reproductively isolated. May or may not match morphological criteria. Speciation is the process by which one species splits into two. Two mechanisms resulting in geographic isolation of two populations. Mimulus cardinalis (flower) and m. lewisii (flower) found in sympatry (occur in same geographic area) Pollinator specialization raises a barrier to gene flow between them. In herbivorous insects, specialization on different host plants can also raise a barrier to gene flow. Epilachna nipponica (type of beetle) on its host plant, thistles. Sister species e. yasutomii feeds and mates on blue cohosh. Reproductive isolation can be pre-zygotic or post-zygotic.
