life forms. Through Darwin’s travels and observations, the Naturalist, a person who studies nature, contemplated common descent as he observed unique animals and plants, which are similar to species in other locations.
The differences between these plants and animals are such, that they provide a distinct advantage for them given their unique locations. This is thought to have likely occurred through natural selection, and from common descent. Darwin ruled out that such differences might be based on chance from random mutations, and concluded that much like selective breeding, the variation of species is due to an evolutionary process where by such plants and animals which had made these changes were more adapt at survival and procreation of the species. This has come to be known as, the process of Natural Selection. Decent with Modification as defined by Perry (2013) is an observable fact to which offspring, at times, can be seen with a difference in appearance, or behavior that the parent, due to some random genetic
mutation. Common Descent, on the other hand, is the idea that there was a single, original species from which all life came. This is an unfounded, and unprovable, says Perry (2013) based on "Facts found independently in the study of fossils, genetics, comparative anatomy, mathematics, biochemistry, and species distribution.” The idea of Common Descent has been rejected by philosophers throughout time as, "You cannot get order and complexity from random chaos alone" as biological make up and mannerisms are thought to be more multiplex, and elaborate than random variation allows for (Perry, 2013). Through the process of Natural Selection, species are better enabled to maximize food supplies, thereby allowing for a greater survival rate of their species. Beneficial traits are thereby replicated in the DNA of their offspring, and this is a vital step in the process of natural selection. For without evolutionary characteristics being passed from one generation to the next, the very definition of natural selection cannot occur. But over time, and with the accumulation of ever increasing evolutionary changes to the species’ DNA, plants, animals, and humans become more distinct, which may result in speciation. It is clear that Jurmain et al. (2014) believe in evolution of the human species as they write on page three of the textbook, “we know that these hominins were anatomically similar to ourselves, although their brains were only about one-third the size of ours” (Jurmain, Kilgore, Travathan & Ciochon, 2014). This can be seen and verified through critical observation and scientific evidence, and this contradicts the ideal of fixity of species, “The notion that species, once created, can never change” (Jurmain, Kilgore, Travathan & Ciochon, p, 27, 2014). Through archaeology, and biological anthropology, we see that the human species, as well as nonhuman primates have in fact have changed over time, and are highly likely to continue to do so.