Monday, March 3, 2014

Darwinism and Anthropology

Darwinism, the most profound theory to account for organic evolution, brought in a Newtonian revolution in life sciences. Charles Robert Darwin, in his books, On the origin of species (1859), put forth an explanation, most alluring and most pragmatic in nature, to account for the progression of life on our very earth. The basic tenets of his theory, to put it crudely, were struggle for existence, Natural selection, adaptation and sexual selection, which was purported later in 1871 in his book, “The descent of man”. Darwinism was a result of meticulous work done on immensely diverse life forms across several continents by him as a naturalist. The extension of his theory towards the course of human evolution could be traced in the descent of man. Darwin had realized that the course of human evolution was not purely biological. He noticed the similarities between the great apes and humans and tried to trace the antecessors of human lineage among the primate world. Also, he noticed that culture leaves an indelible impression on human lives, thus considered it as one of the contributing factors in the course of human evolution.
Darwinism in anthropology assumed importance much later. As we all know, anthropology is a distinctive field of inquiry concerned with the existence of humans in time and space. However, till the mid-twentieth century, we find a woeful lack of evolutionary approach in understanding human diversity. Darwinism was adopted veraciously by anthropology only after the prologue of modern physical anthropology initiated by Sherwood Washburn in the year 1951. Before this year, the anthropological investigation was classificatory and descriptive in nature, where primary focus was to delineate the human biological diversity in to races and sub races. The concept of pure races and ideal types flooded the anthropological literature. Washburn directed the focus of anthropology towards an empirical evolutionary framework in the realm of variations and diversity found amongst the human population. The concept of population replaced the concept of races, marking the solemn beginning of Darwinism in anthropology.  An experimental approach and cross disciplinary collaboration ensued in order to explain diversity. Washburn stressed particularly upon the functional anatomy, comparable to Malinowsky’s structural-functional approach and behavior analysis while introducing the expositions of modern physical anthropology. Bio-cultural studies fabricated with evolutionary approach infused Darwinism and anthropology courteously. 
From here onwards, we find an unvarying interaction between Darwinism and anthropology. Advances in the field of skeletal biology, Paleoanthropology, serology together with the exponential developments in genetics, we find a strong Darwinian approach in the inquisition of human variation. However, as genetics advanced, a large number of molecular phenomena were revealed which strayed away from Darwinian processes. For example, Darwinism, or rather Neo-Darwinism assumed that environment has a nearly negligible role on the transmission of genetic material. Variations produced were considered to be random and environment has no significant effect on it. But discovery of Epigenetic mechanisms, referred to as Neolamarckism, have challenged this notion. RNA interference, feedback loop mechanisms, DNA Methylation, chromatin marking systems and other epigenetic processes have severely challenged such assumptions of Darwinism. Similarly, advances in the study mutations have challenged the assumption of Darwinism that a cornucopia of variations exists in the population and natural selection acts upon them. Kimura Motoo has worked extensively to demonstrate the role of mutations in the course of evolution. His main argument was that the most of the mutations are selected by random genetic drift rather than natural selection, as the nature of a large number of mutations is neutral. His work has been extended by Mashotoshi nei, who has shown the positive effect of mutation processes in generation of alleles. Mutations are not merely a substrate for natural selection to act upon; they have the tendency to affect the process of evolution themselves. Another diversion, paramount to anthropologists, is the impact of culture on human evolution. More aptly termed as learned inheritance, humans have a tremendous tendency to abate various environmental constraints using cultural tools. Biomedicine, agricultural revolutions and so many other things have enabled humans to break away from the clutches of natural constraints. So, Darwinism again is heralded by such interventions.
In all the above cases, we find that Darwinism as a theory do not suffice to explain the evolutionary mechanism, especially when it comes to humans. The process of evolution is tremendously complex and the tenets of Darwinism are not the only explanations. But here, I would like to take a pause and try to distinguish between the two facets of Darwinism. As I have explained already, Darwinism as a theory might have shortcomings. As we are delving more and more at molecular level, we find certain departures from Darwinism. But Darwinism as a philosophy to account for the progression of organic world cannot be denied.  It can be compared to the discourse of gravity in the field of physics. Initially it was put forth by Sir Isaac Newton. He described various laws to account for gravity and proposed the process involved.  Surely, his laws have been proved wrong, with advances in the theory of relativity and quantum mechanics. But even today, the broader framework of gravitation is still bases on Newtonian principles. Similarly, the tenets of Darwinism might not be able to explain the process of evolutions as a whole, but we cannot depart Darwinian philosophy from the course of any evolutionary study. Darwinism offers an insight in organic world which has the potential to explain the existence of every life form on our earth. Unless we start believing in intelligent design, we have no other option. 
Darwinian philosophy posits that every life from, including humans, had a common origin. Every individual organism becomes an agent of evolution, striving hard to ensure the existence of life on the planet. Every individual competes with others to leave a stubborn mark of his existence by reproduction. Organisms of all kind, sharing the time and space, are racing against each other to prove themselves to be successful. And in between this process, we find the concept of speciation and adaptation. Also, Darwinism respects the anonymity of evolution. When understanding the evolutionary past and future, we can only guess, we may never know. Darwinism states that the course of evolution of any organism is decided by the changing environment. It is not a goal directed process, but a never ending process which will end when life comes to an end. Under the purview of Darwinism human intelligentsia is just a path for survival, similar to the beak of a hornbill or trunk of an elephant. Some organisms adapted physiologically, some anatomically and we adapted consciously. Culture can be considered as the extended phenotype (Dawkins, 1981), an extrapolated expression of human capabilities. So, under this purview of Darwinism, we find that it is implicit every domain of Anthropology.
In contemporary times, the anthropological research has become diverse, very diverse where the bio-cultural interactions and their impact on human evolution are being contrived. I would like to cite a few discourses in anthropology that elucidate the importance of Darwinism in anthropological inquiry. 
A specific school of thought, which embodies the very spirit of Darwinism in anthropological research, is the gene culture co-evolutionary theory. It began in early 90’s where the effects of genes and culture on each other were equated. William Durham, a physical anthropologist, has tried to summarize the interface between genes and culture. He has proposed several comparative modes where genes and culture interact. In certain cases, both enhance each other as in incest taboos which prevent inbreeding favorable for the transmission of genes, reducing the chances of recessive genetic disorders. Sometimes, they oppose each other such as the practice of cannibalism among the Fore people which leads to neurodegenerative disorders. Also, he has proposed two interactive models termed as genetic mediation where genes select among the cultural variants. He elucidated it with the example of mating strategies such as Tibetan fraternal polyandry) and cultural mediation where culture selects among genes, such is the case of lactose absorption. This theory has tried to put together the co-evolution of both genes and culture along Darwinian selection.
Another emerging area of anthropological interest is the resurfaced concept of sexual selection. The concept of sexual selection was subverted by the neo Darwinists as they primarily assumed a panmictic mode of mating. Hence, the concept itself submerged under the circumstances. In last three decades, special emphasis is being given to the effects of sexual selection as it provides a theory of reproductive competition, along the Darwinian lines. Both the phenotypic expressions and cultural displays are being studied by anthropologist to trace the course of sexual selection and its impact on human evolution. Geoffrey F. Miller, an evolutionist, has explained the predicaments of sexual selection in a bio-cultural framework. The selection of light eye colors among the European population might be explained in terms of sexual selection by him, where he regarded that the lighter eyes had no appreciable fitness value, but they were a fitness indicator readily selected in their culture as a preference in the respective mate. Similarly cross species studies in mating behavior are also being done. They are produced in a Darwinian framework where competition ensues for a better mate. For example, a study done by A. H Harcourt, a physical anthropologists from university of California has revealed a correlation between the testis size of males and mating strategies. Relatively larger testes, which produce large quantities of sperm, suggest a degree of polyandry since the sperm from two or more males have to compete in the uterus. Chimpanzees have relatively large testes and low degree of sexual dimorphism and females engage in coitus with multiple males when in estrus, indicating a strong sperm competition. Similarly, gorillas have small testes and a high degree of sexual dimorphism and we find that gorillas do not engage in sperm competition but physical competition, where a male tries to protect his harem. Humans are intermediate between the two in respective body and testis size, suggesting that ancestral human males engaged to some degree in both sperm competition and physical completion while mating.  
Similarly, the human genome project has taken the study of genetics on a whole new level. Various projects such as human genome diversity project and many other are being undertaken by evolutionists, geneticists and anthropologists together to trace the origin and dispersal of various populations on the globe. These studies are also based on Darwinism. Genomic studies can be termed as the quantum revolution in life sciences. The efforts to trace the humans migration is a conflation of genomic studies as well cultural elements such as language. Culture has been with us since the beginning, so it goes hand in hand to a large extent, with biological dispersal. 
One more fascinating example of contemporary anthropological research is to understand the nature of Human sociality and human behavior. Evolutionary psychologists, anthropologists and many others are trying to the trace origin and sustenance of various universal cultural elements which have aided the survival of human. Pascal Boyer, an anthropologists who have worked primarily among the kurus of the fore, has done some excellent work in tracing the psychological predisposition of humans towards religion and have explained how this peculiar understanding have survived overtime in his book the religion explained. Robin Dunbar has tried to uncover the nature of human sociality in terms of neurological adaptation. So, our every endeavor to understand the nature of human evolution entails a Darwinian notion. Hence, in contemporary anthropology Darwinism is as profuse as it ever was.