EVOLUTION: ANTHROPOLOGY

Evolution: Anthropology

Evolution: Anthropology

Answer 1)

Darwin's theory of evolution by natural selection (Darwin, 1859) describes the world of organisms as a world of competition for survival and replication. Due to the high fertility rate of most populations, within a few generations the world would be overcrowded by most species, but in fact we observe in most cases an almost steady state of population. From that observation, Darwin infers that there must be strong competition for the resources organisms need; that is, not all individual organisms that are born are in fact able to survive and to reproduce (the struggle for existence). The next step is the fact that individuals of the same kind slightly differ in their qualities and that often certain varieties are inherited (Darwin refers to knowledge from the field of breeding). In the struggle for existence, those qualities that lead to better survival chances (natural selection in a narrower sense) and higher chances of reproduction (sexual selection) will thereby necessarily be more often present in the next generation than maladaptive features or disadvantageous traces (Smuts, 2005).

This process is labeled by Darwin, in analogy to humans' selection in breeding, natural selection . Natural selection “chooses” from the occurring differences (mutations) those features that tend to increase fitness, and Darwin infers that this process leads over a long time of accumulation of small differences to the origin of new species and to the astonishingly complex and highly functional adaptations (designs) that we find everywhere in nature. Darwin was of course not the first scientist to hold the view that species have evolved, but he was the first to discover-independent from but consistent with the ideas of Wallace (Darwin & Wallace, 1858)-the causal mechanism (natural selection) that is responsible for the generation of all the observed adaptations of organisms.

This shifts the mean value for the selected characteristic during successive generations in the descendants: The breeder is applying directional selection to the particular trait of interest (the somewhat unfortunate term “artificial selection” is often applied to this methodology, which could be misconstrued). Darwin expands upon this discussion in The Variation of Animals and Plants Under Domestication (1883) and states that domestication is a gigantic experiment in selection. Modern discussions of the principles and results of plant and animal breeding are couched in terms of genetics.

Answer 2)

Evolution “on a small scale,” over a number of generations rather than over millions of years, has been achieved under domestic and experimental conditions and observed in the wild. The origin and development of domestic breeds of animals and plants has been a topic of interest to anthropologists and clearly demonstrates that species change. In On the Origin of Species (1859), Charles Darwin discusses the production of domestic breeds as the result of “accumulative selection” by humans and points out those breeders and horticulturalists intentionally modify breeds within a human lifetime. He particularly concentrates on the origin of pigeon breeds. Darwin also addresses “unconscious selection,” in which a breed is altered simply by breeding the “best” individuals ...