Life on earth evolved gradually beginning with one primitive species – perhaps a self-replicating molecule- that lived more than 3.5 billion years ago; it then branched out over time, throwing off many new and diverse species; and the mechanism for most (but not all) evolutionary changes is natural selection (Coyne, p.3).
Of course, this is a modern definition of evolution, informed by scientific discoveries that have helped shape the understanding of the age of the earth in comparison to the ages of plant and animal species. When Darwin first proposed the theory of evolution, it did not begin with an understanding of the earth’s age and was not backed by as much evidence from the fossil record. Instead, he began with the premise that plant and animal species evolve. This evolution simply refers to a series of genetic changes over time. Moreover, these changes are generally going to improve …show more content…
However, this argument ignores the theory underlying natural selection. Natural selection suggests that those members of a species that are best-suited for survival in a particular environment will be more likely to reproduce in that environment. As a result, those traits will, gradually, become more prominent in the population, which will change the species’ overall genetic makeup over the course of several generations. However, certain events can hasten natural selection, so that some species may evolve much more quickly than other species. Furthermore, if an environment remains relatively stable and a species is already highly functioning within that environment, one would expect to see few, if any, changes to that species over