Sunday, March 21, 2010
No, really, what about us?
In chapter 8, "What About Us?" Coyne brings up the question of whether humans are actually de-evolving. On the one hand, the development of lactose-tolerance in pastoral populations is proof that human evolution has occurred within the last 3,000 to 8,000 years (Coyne 217). On the other hand, medical intervention has made it possible for "less fit" individuals, such as those with bad eyesight and bad teeth, to reproduce (Coyne 218). What do you think? Are humans still evolving, remaining the same, or de-evolving? Give evidence to support your answer. (Remember that the overall goal is merely to survive and reproduce, not necessarily live long.)
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Even though the changes in the human race are not that prominent, I believe that even with some humans out there "de-evolving," I still believe that there is some evidence that the human race is changing, even with such small changes.
ReplyDeleteI first want to point out that the term "de-evolving," as Coyne uses it on page 219, is, to an extent, actual evolution. Even Coyne admits it himself, as he describes that humans are “becoming more adapted to modern environments that create new types of selection” (219).
The definition of evolution that Campbell gives describe “de-evolution” as a form of evolution. A few of Campbell’s definitions of evolution include “Descent with modification,” and “A change in the genetic composition of a population from generation to generation” (452). Is the human population’s tendency to show distain towards fatty foods really “de-evolution” (Coyne 219)?
The answer is no. This would be similar to saying that flamingos and dodo birds “de-evolved” too when they lost their ability to fly*. Instead, they, as Coyne iterated, are just “becoming more adapted to [their] modern environment…” (219).
I also assert that humans are evolving because we are gradually gaining intelligence. Somewhere in Coyne’s novel (I’m not going to leaf through every page just to find one sentence), Coyne mentions that human IQ is gradually increasing by a very small decimal. Remember that Coyne states that “gradualism” is an element of evolution. Even IF this 0.0001% increase in intelligence every 100 years is small, it is gradual. The Archaeopteryx in Coyne’s novel didn’t achieve the ability to fly in just a few centuries (41). It had to wait millennia to finally build up the gene that promoted feathers and the physiology to lift itself off the ground. Homo Sapians have inhabited the Earth for less than half a millennia. It is far too early to say that we do not have the potential to evolve, and that we are not evolving.
The gradual development of wings is a process of continuity and change. Structures that once did not serve the purpose of flying gradually were passed down by genes. However, these genes were modified to eventually become wings that the organism could use.
Someday, humans may have double the intelligence that we have now. Considering that we have already constructed crafts that could take to space, bombs that could wipe out entire countries, broken the sound barrier, and other feats, we have the potential of ruling Earth.
*I’m just using the dodo bird as an example. I know that the dodo is extinct. However, it did lose its ability to fly because it was undisturbed for centuries before Portuguese hunted them to extinction.
I would have to argue against Henry's point and say that humans are indeed de-evolving. Because of advancements in science and technology aiding human survival, human genetic fitness has become less important to the mission to survive and reproduce, and therefore human evolution can reverse because bad genes remain in the gene pool.
ReplyDeleteAnd to argue Henry's points:
Human disdain for fatty foods is crafted by human culture rather than human evolution. Isolating a human from day one of development would produce a human that has a preference toward fatty foods. The reason humans are attracted to fatty foods is that the humans developed a taste for fat when food remained scarce and high energy foods such as fat aided survival.
I would argue that do-do birds have de-evolved. As you bring up, dodos were hunted to extinction because they had become more fit for the current environment. In doing so, dodos became less adaptable toward change, in this case the arrival of predators in the form of Portuguese sailors.
Human evolution is not the reason that humans are becoming more intelligent. This is another product of changes in society. Human education has improved over time, therefore increasing human intelligence.
It is true that evolution takes millions of years to occur. As it is, humans remain fairly fit for survival in non-civilized locales. Human fitness to survive has decreased, however, but very gradually. An example of this decreasing fitness is the development of food allergies that make individuals less fit for survival by cutting off sources of energy. In the US, food allergy rates have nearly doubled over the last decade (http://www.cdc.gov/nchs/data/databriefs/db10.htm) Fitness for survivalship has decreased faster in some areas than others, however. Note how peanut allergies occur in great numbers in developed countries but in much lesser numbers in developing countries. Because environmental conditions in developed no longer require for humans to have access to many sources of energy, more individuals with food allergies will reproduce and therefore make humans slightly less fit for survival.
Nevertheless, these traits could eventually become positive, as wings did for the Archaeopteryx. It seems unlikely to me that food allergies would ever develop to become helpful, even over several millions of years.
If human intelligence indeed does increase, and this intelligence has aided our development of the atomic bomb, I may find it worthwhile to argue that human intelligence may be a bane to human survival rather than a boon.