Speciation:
1) The production of new species from previously existing species.
2) It is thought to occur as a result of a species dividing into two isolated subpopulations.
3) If two subpopulation contain some genetic differences and their environments are somewhat different, natural selection will work on the two groups differently and they wil begin to diverge from each other.
4) Eventually, the differences may be so great that the two subpopulations are not able to interbreed. At this point, they are two different species. (Fig. 5.13)
5) For plants, polyploidy is another common mechanism results in new species. Polyploidy is a condition in which the number of sets of chromosomes in the cells of the plant is increased.