Web Paper 2
The Culture of Evolution
Evolution has been used as a metaphor to describe cultural change, especially in this class. We have been discussing biological evolution and cultural evolution as two separate entities, when I think both greatly shape one-another. Our culture can shape our biology, whether it is technological innovation to help us adapt to an environment or how we can actually change the environment we live in.
The agricultural revolution shifted humans to a stationary life-style, where the domestication of animals could supply a steady food source. Another source of nourishment that was provided by this shift in behavior was milk from cows. During the beginning of this shift, however, adults were not able to digest milk sugar (lactose) (Pritchard 45). This was because the gene that codes for the enzyme lactase, which breaks down lactose, was shut off after infanthood (Pritchard 45). A mutation in this process, however, gave people who could break down lactose an advantage over others because milk is a quick and efficient way to gain protein and other nutrients. The cultural shift, coupled with the gene mutation, fed into each other. This behavior and societal structure became advantageous because of a biological mutation, and the mutation became largely dominant in the population because of the social structure!
The ability to make tools has also enabled us to more easily manipulate the environment. This innovation has led to our ability to change the flow of rivers, turn swampy areas into a cities, and even build our own lakes. As we change these environments to better suit ourselves, however, we are also changing it for the wildlife we share it with. How far is too far? We often take pride in our cultural abilities, and often see our intricate social structure as a way to set us apart from the rest of the natural world. These social intricacies are not exclusive to us, however, and some aspects of our “progress” may not beneficial to humankind as a whole.
Cultures widely vary between geographical areas; whether it is different customs, ideologies, or language, there are a lot of things that can cause social barriers amongst different groups. How can culture shape evolution? There is a lot of mixing between human populations today, but how can “cultural” barriers play a part in the animal kingdom? Last year in my biology class, we read a book called The Beak of the Finch, by Jonathan Weiner. I was surprised the find how behaviors play such a large role in molding the genomes of these Galapagos inhabitants, and how mating occurred solely based on the language of these birds. The Grants, who have been researching the finches on the Galapagos island of Daphne Major since 1973, have collected a myriad of observations about these birds (Weiner 9). They observed that in two different species of finch, females mate with males that sing the specific song of their species (Weiner 164). If a male accidentally learns the song of a neighbor, the Grants observed that the females will not mate with him because he is singing the wrong song (Weiner 164). It is interesting because even if the male demonstrates a genetically favorable beak, the female will choose his ability to sing the right song over the beak (Weiner 164)! The song, which is a learned trait and not a genetically inherited one, plays a large part in whether or not the finch will be able to pass on his genes (Weiner 164).
Another way in which these finches shape their evolution is seen with the cactus finch. There are a select few finches that have figured out that if they remove the stigma off of cactus flowers, they can get more pollen and nectar from the flower (Weiner 291). This behavior may allow a quick, tasty snack for the finch, but it leads to sterilizing the flower and therefore cutting down the amount of food available for the finches in the following year (Weiner 291). Even though only a few finches do this for an immediate food reward, it is harming the chance for survival for the rest of the group. Weiner writes “It is hard to imagine a simpler, neater, faster way for a species of Darwin’s finches to drive itself toward extinction” (Weiner 290).
It is amazing to see the parallel between the Galapagos finches and us. Although different languages do not create as strong a barrier as it does in the finch population, people who can’t communicate will often not be compatible with one-another. The few finches that are harming the food supply for their population in the future is similar to “tragedy of the commons” in our culture. This is the notion that people may over-use or pollute natural resources so that it impacts everyone else. There may be many environmentally conscious people in the world, but it only take actions from certain groups to harm what belongs to everyone. Clean air acts, recycling, decreasing pollution can definitely add balance to our interactions with nature, but it only takes one oil spill to cause great harm to what is shared by both people and wildlife. Acts can be passed in a certain country, but if another country continues to keep pumping pollution into the air, it still impacts everyone. Do we have the capability to cause our own extinction?
The world is has changed tremendously over it’s lifetime. Species have come and go, climates have fluctuated, and civilizations have prospered and fallen. We are not immune to change. Our ability to solve problems and shape our environment has lead to our ability to thrive, but it may also lead to our own destruction. Industry has been considered a miraculous tool to move humankind forward, but our ability to manipulate the natural world my ultimately lead to our own demise. If we continue to use natural resources and do not force ourselves to change this habit, there is nothing to guarantee that it will all work out. We as a human race are in our teenage years, believing that we are invincible. Even if some of us or certain countries decrease cutting down trees or destroying environments for our own personal gain, it will not make a difference if others choose to continue this behavior. Even a select few can destroy our future, just like the select few cactus finches destroyed their own chances of surviving. So are we the cactus finch, too focused on rewarding ourselves now and not enough on how we’re impacting our future?
Pritchard, Jonathon K. “How we are Evolving”. Scientific American: 2010 October.
Weiner, Jonathan. The Beak of the Finch. New York: Vintage Books, 1994.