Speciation. The biological species concept has its limitations (although it works well for many organisms and has been very influential in the growth of evolutionary theory).
In order to address some of these limitations, many other “species concepts” have been proposed, such as: Recognition species concept: a species is a set of organisms that can recognize each other as potential mates. Even though these two frogs have been prevented from mating, the fact that they recognize each other as potential mates makes them the same species under the recognition species concept. Phenetic species concept: a species is a set of organisms that are phenotypically similar and that look different from other sets of organisms.
According to this concept, phenotypic similarity is all that matters in recognizing separate species. Defining Species. While Darwin entitled his book "On the Origin of Species", the book dealt primarily with a mechanism of evolution (natural selection) in which variation was critical. But what will selection do with this variation? Change the frequency of dark morphs of moths, or morphs of snow geese, or change the mean and the variance of the distribution of heights in human populations? Spec.pdf (application/pdf Object) Predator prey density aggregative. Logistic Growth. Phylogenetic species concept.