The advent of global economies, the increase and ease of international travel habitation, and the advances in telecommunications have blurred geographical, social, and political boundaries exposing the limitations of many traditional and existing frameworks from which we define and perceive human variation. Darwin's theory of evolution provides us with great insight into the development of human species (phylogeny) and its mutability over time, but nay be incomplete in describing differential development within the human species (ontogeny). Nonetheless, his theory has exhibited a great influence over scientific research and provided a strong impetus for fields such as evolutionary biology and genetics. This article will, first, briefly review Darwin's theory of evolution and its historical significance. Secondly, a comparison will be made between Jared Diamond's (1999) conceptualization of human development and variation. Thirdly, an example of individual development in the field of athletics will be presented, addressing the limitations of the two theorists.
In his seminal work, On the Origin of Species, Charles Darwin (1859) posed his theory of evolution which argued that contemporary human beings, along with other species, were modified descendants of a less resilient breed. Over a long course of time, he explained, traits that were necessary for the survival of the human species were passed on to successive generations while those that became unnecessary were eliminated form the species. He believed this process to be extremely slow occurring and likely to be noticeable only over the course of several generations, departing from Lamarkian evolutionary thought (Crain, 1992).
Darwin proposed that evolutionary change occurred in two steps; variation and selection, more commonly known as "natural selection." Variation consists of traits randomly being introduced into the species by mutations in the organism. Darwin believed that the human species consists of innumerable variations represented by the diversity seen among individuals. He did not, however, include in this theory an explanation for the cause of variation and was duly criticized for this omission (Darwin, 1859). Other scientists later revealed how variation took place through mutation and the interaction of dominant and recessive genes.
Natural selection, the second step of evolutionary change, consists of the slow natural process of eliminating those traits from the gene pool that do not enhance the likelihood of survival and reproduction while selecting those traits that do. This process occurs through the infertility and death of those who are carriers of weaker traits so that these traits cannot be passed on to following generations. Carriers of those traits necessary to survive were able to reproduce and pas on their traits through reproduction. Hence, evolutionary change is a process that is driven by the organismís motivation to survive and procreate. This drive is more commonly known by the familiar phrase, "survival of the fittest" and provided the foundation of Darwinís theory (Darwin, 1859; Crain, 1992).
In addition to the heritability of strong character traits through natural selection, Darwin posited that some organs and senses become "rendered useless" when changes in the environment no longer require their exercise. Modification through "disuse" was believed to occur only in mature organisms (Darwin, 1859). Likewise, those organs and senses that proved useful and were exercised most in the struggle for existence became more developed.
Darwin's (1859) theory, though not the first theory of evolution, was groundbreaking because it was the first theory of evolution to be so well thought our and provide clear scientific evidence to support its claims. Unlike Lamarkian evolutionary theory, Darwin believed that adaptations within species only became noticeable over long periods of time spanning several generations. He did not believe that new traits were acquired and passed on to successive generations through habituation (Crain, 1992).
Darwin's (1859) theory of evolution has had a lasting impact on the way we perceive human variation and the potential to facilitate change. The introduction of his theory was very controversial and challenged Locke's (date) notion of environmentalism, which believed the human organism to be malleable (Crain, 1992). Locke believed that all individuals had equal potential and that any observed differences were due to environmental circumstances (Crain, 1992). In addition, Darwin parted with other prevailing beliefs of his time, namely creationism and Platonism. These ideologies held that species were immutable and existed in their original forms (reference). More specifically, Platonists held that variability in these original forms was attributed to perceptions rather than real differences. For discounting these existing beliefs, Darwinís theory was heavily criticized and met with great opposition.
Jared Diamond (1999), more closely aligned with traditional environmentalists, would not fully disagree with Darwinís theory of natural selection with regard to the human species; however, he argues against its use to explain individual and group differences among humans. For instance, in Diamond's book, Guns, Germs, and Steel, a local New Guinean politician, Yali, poses this question to him, "Why is it that you white people developed so much cargo and brought it to New Guinea, but we black people had little cargo of our own (p.14)?" This native of New Guineal was seeking an explanation for the development of modern technologies by Europeans while his native New Guineans remain technologically primitive. He wonders what ìitî is that allows one group to flourish, while another remains unprosperous. In answering this question, Diamond writes, "History followed different courses for different peoples because of differences among peopleís environments, not because of biological differences among people themselves (p.25)." He attributes variations in the species to environmental factors.