How did Homo sapiens become Homo sapiens? Was there a miraculous shift in our DNA a millennia ago that caused our ancestors to morph into what we see today? Or was it a series of gradual changes over that same millennia? The two schools of thought on evolution are phyletic gradualism and punctuated equilibrium. Both present compelling arguments and are at odds with the other. I believe Homo sapiens were created by a millennia of small changes occurring gradually, before we get to that however let us further examine the schools of thought.
Phyletic gradualism is the idea that genetic changes occur constantly and very slowly over long periods of time to produce a species. Speciation in this manner was proposed by Charles Darwin (Saylo, Escoton & Saylo, 2011). Darwin proposed that it was the process of natural selection gradually weeding the unfit from the population thus creating a new species. The theory of phyletic gradualism states that evolution occurs all the time and is not concentrated into short bursts of genetic mutation to create a splitting of species.
Punctuated equilibrium is the evolutionary theory that describes the process of speciation where long periods of stasis are followed by bursts of genetic mutation resulting in a splitting of species into two distinct species. One having the new morphological changes and the other not. This does not run contrary to the theory of phyletic gradualism however.
It is believed that a species can evolve using either or both of these methods. Both are supported by the fossil records and both are supported independently by the fossil record. During periods of gradual change the fossil record should include all stages of development from ancestor to new species over several layers in the record. During periods of punctuated equilibrium we expect the fossil record to show ancestor and new species very close together in the record. Both of these are found according to the Society of Evolutionary Biology (Society of Evolutionary Biology, 2012).
One of the facets of punctuated equilibrium is the prolonged period of stasis or non-evolution. Scientists theorize that these can be explained by the...