Week5 Draft3

Speciation is the evolutionary process by which new species arise. Although the definitions of what a species is does vary, the mechanisms by which these differences among species arise is consistent. Two types of speciation are sympatric and allopatric speciation. In sympatric speciation, a single species diverges to become two distinct species due to sexual preferences, a separation by a reproductive barrier, or polyploidy. Over time, a single area may have a population experience distruptive selection. For example, a group of beetles that breed within flowers of a plant, but if the plant has a mutation and produces a new colored flower, one that would attract certain beetles, the separation and preference causes the species to diverge. This is an example of pre-zygotic, behavioral isolation. In allopatric speciation, a separation, a geographic barrier between a once united group may cause the species to diverge. For example, in a pool that dries up and creating smaller pools, the fish that were once together are now separated geographically. Over time, the fish will exert a preference for their own kind if re-united. This too, is an example of speciation of a single species, now separated by preferences due to evolution.