Professor Stone’s lecture began by reframing the iconic image of evolution: the walking man. This image represents a false sense of evolution in that it suggests that the process of evolution is a ladder, that it has a goal and thus and end, and it reinforces the typological thinking pattern that one species can be represented with a perfect type. In reality, evolution is a branching process where do species diverge from a common ancestor, it is not a ladder-like line where one species develops completely into another in one step working towards an idealized form. Darwin’s idea of branching and natural selection makes it possible to relate different species by exploring their common ancestors–a theory that resulted in a massive paradigm shift. Darwin’s ideas also contrasted Plato’s philosophy on forms, which was widely accepted at the time. The application of Plato’s theory in evolution suggests that there is an ideal essence which development works to achieve, and thus evolution has an end. In this realm of thought, each species would also have an ideal form. Darwin overthrew these theories by demonstrating variation within species. He showed that this interspecies variation actually drives evolutionary processes since different combinations of traits contribute to different levels of fitness. When a specific combination leads to increased fitness, it becomes more prevalent in a population throughout time. If this population is isolated it can lead to speciation.
The synthesis of genetics with evolutionary biology lead to massive paradigm shifts in scientific thought and culture. When the study of phenotypes is combined with patterns of inheritance the source of certain traits can be extracted. The synthesis of genetic and biology has lead scientists to discover the origin of the human species, from 14 populations in Africa, and see how this species spread throughout the world. The most pertinent discovery that stemmed from the unification of evolutionary biology and genetics was the realization that there is no biological reality to race. This discovery not only lead to shifts in medicine, but also caused some controversy in society. Before this discovery typological thinkers had developed different medicines for people of different “races.” These medicines were not based on individuals, but rather trends of efficacy within their “races.” Now that genetic information is accessible scientists can see that there is no “race” for which a certain medicine works best, but that it depends on the genome of each individual. There are trends in diseases that groups of people may acquire based on their environments; however, this does not mean that only certain types of people are susceptible to these diseases.
The discovery of the absence of race also contributed to a paradigm shift throughout society. Before this realization, categories for types of people were established based on their phenotypes. The leading classes of each society used these categories to arrange the social hierarchy, which only further socially segregated groups of people and contributed to racism. In reality phenotypic variation lies on a continuum, thus it is impossible to assign a race to every human since there are infinite combinations of these phenotypes. The synthesis of genetics and evolutionary biology also lead to the realization that phenotypes do not always rely on specific genes, there are many complex causes. Professor Stone referenced the spurious results of twin studies which assumed that two individuals with identical genomes would have the same phenotypes for everything. The results from these studies are inconclusive since they fail to realize that environmental factors contribute to phenotypes.
Professor Browne introduced the idea of the unification of genetics and evolutionary biology several weeks ago. The study of genetics was considered revolutionary when it was first introduced, and Darwin’s theories on evolution and natural selection caused massive paradigm shifts within the scientific community and the world at large. Professor Stone’s lecture explained how the unification of two revolutionary branches of science lead to massive shifts in scientific thought and the construct of society.