preview

Biology: What is Speciation?

Good Essays
The process of speciation, which has been studied by biologist for centuries, is difficult to explain. Speciation is the process of forming a new species. Charles Darwin is one of the most famous persons to study different species and how natural selection had an effect on evolution; however he never discussed how one species gives rise to another. It is known that there are theories of how speciation takes place. The four models for speciation are allopatric, sympatric, peripatric, and parapatric speciation. In speciation, there are two factors that need to occur. One is that populations diverge. The second is that populations were kept isolated. The roles of mutation and natural selection are important in speciation.
So first, to describe the role of natural selection in speciation process, a simple definition of what natural selection is must be given. Natural selection is the process where organisms better adapted to their environment tend to survive and are able to reproduce. Natural selection is one of the basic mechanisms of evolution. If you have variation, differential reproduction, and heredity, you will have evolution by natural selection as an outcome. In Darwin’s theory of natural selection, an example is given of giraffes. In this example of the giraffes, Darwin suggests that variation was a result of preexisting genetic differences among the giraffes. While this other biologist Jean-Baptiste Lamarck, believed that evolution occurred by the inheritance of acquired characteristics. He believed that the giraffe ancestor lengthened its neck by stretching to reach tree leaves, and then passed the change to the offspring. However, Darwin believed that some giraffes were just born with longer necks due to genetic diff...

... middle of paper ...

...s from the two ends mated with each other they could not produce fertile offspring. In parapatric speciation there is no specific extrinsic barrier to gene flow. The population is continuous, but nonetheless, the population does not mate randomly. Individuals are more likely to mate with their geographic neighbors than with individuals in a different part of the population’s range
Peripatric speciation is similar to allopatric speciation in exception to size. In peripatric speciation a small population is isolated at the edge of a larger population. Notice that in peripatric speciation, small population size would make full-blown speciation a more likely result of the geographic isolation because genetic drift acts more quickly in small populations. Genetic drift would cause rapid genetic change in the small population. This genetic change could lead to speciation.
Get Access