Natural Selection: Traits Favored in Frugivory
In her article, “Diet and Primate Evolution,” Katie Milton discusses the correlation between various primate diets and natural selection, specifically targeting frugivory and its necessity for enhanced intelligence. In order for primates to exist almost entirely on fruit, which many, including chimpanzees do, they must develop certain traits necessary for obtaining sustenance. “Natural selection strongly favors traits that enhance the efficiency of foraging” (Milton,86).
These traits include hands that can both grasp and swing, but also gently grasp and open delicate fruits and plants. Visual traits, such as “depth perception, sharpened acuity and color vision” are favored as well, as they help primates navigate quickly through trees and other obstacles, while still detecting fruits and other edible vegetation around them. According to Milton, these kinds of adaptations promote the development of a larger brain.
Natural Selection in Relation to Diet in Humans
Likewise, Katie Milton theorizes that humans turned more and more to hunting and a carnivorous diet when there was less variety and sources for protein in plant-based sustenance. They used their large brains to commit maps of where to find food to memory. They must’ve also learned how to find and recognize stones that can be used to make tools, then to make the tools and implement them.
In addition, they were forced to co-operate with others in their party and to “defer gratification”, by waiting to eat their kill until all members of the hunting party were present. Once this was achieved, a system of equal/fair food distribution had to be implemented as well. Speech would have been very useful in situations like these and could’ve developed out of need for this very reason. In fact, Milton theorizes that much of human evolution and emergence was due to the need and search for proper nutrition and significant protein. In light of this, it is interesting to consider the current craze in high protein, low carbohydrate diets, such as Atkins and South Beach. Perhaps this is our collective genetic memory, reminding us, as humans, what was beneficial for our ancestors.
A Convincing Theory
Katie Milton’s argument in this article is absolutely intriguing and quite convincing. Her explanation of modern day New World primates, the spider monkey and the howler monkey serves as excellent evidence in these theories, as it charts differences between diet and digestion and brain function between the two. This clearly illustrates the divergence that can develop between similar creatures, based on diet, nutritional needs and available nutrition. Please reference the original Scientific American article, linked above, for more information on this extremely interesting study.
Bibliography:
1993 Milton, Katherine. "Diet and Primate Evolution," Scientific American, pp. 86-93.
Heidi Griffin - Heidi has written for numerous local newspapers and magazines, as well as several internet sites. She specializes in film theory and ...
