As humans, we like to think of ourselves as the endpoint of the evolutionary process while we are actually just another branch on the evolutionary tree. I say tree instead of ladder here because of the common misconceptions that evolution is a moving forward process that enforces typological thinking. At many points in history, we have had many conceptions of evolution and many ideas of categorizations within species.
We can begin exploring the idea of evolution before we explore the concept of Darwin’s evolution. The pre-Darwinian ideas fell under the idea of the Great Chain of Being, which was accepted from roughly 500 AD to 1700AD. The Great Chain of Being is what it sounds like, a ladder-like chain of evolution. When Darwin came about, the revolution truly started. Darwin came up with the idea of evolution as a branching tree, otherwise known as the branching tree of common descent. The idea of evolution by natural selection was a truly revolutionary idea that has continued to drive our ideas behind evolution even today.
Darwin’s idea was supported by ideas from great thinkers such as Plato and Aristotle. Plato’s Theory of Forms followed the idea that every object or quality has an idealized essence. Aristotle’s Biological Classification said that species are categories or types within broader categories such as genera. This implies that if species are types, then the variation that we see within species is imperfection. Darwin saw this variation, and recognized the centrality of this variance within the species. This variation within species is the raw material necessary for natural selection. Species do not suddenly adapt, but adapt from the ideal traits that aid them to lead better lives and hence naturally select.
Within evolutionary biology and genetics, there have been two main types of scientists, biometricians, who believe in natural selection of small changes and mutationists who believe of the transmission of large differences within a species. Mutationists studied the inheritance of discrete traits. Evolutionary biologists believed that they had reconciled this with their own evolutionary theories.
This mutationist, typological thinking has been further reinforced through the ascendance of “the gene” in the public mind. This emergence of the gene has had impacts that are trivial, irresponsible and criminal in evolutionary biology. Something that needs to be realized, however, is that we do not have types and that human genetic variation is continuous. This is evident in that most human variation occurs within populations instead of among “types”. The discovery of “the gene” has led to race being a differentiator for medicine used to treat different people. This is not a good medical construct, as when we take a closer look, it becomes apparent that disease probabilities do not go significantly up or down when we look at race, variable traits within any race have complex causes. Instead, we should be looking further into mapping the genome and exploring further the concept of personalized medicine.
With all of these revolutionary ideas being proved and disproved, and species constantly coming in and out of the world, I think that it is too bold of a claim to say that humans are the end point of evolution. In a few hundred or thousand years, I am excited to see what we have evolved into.