Western Society: Do We Control Natural Selection?

LS's picture

Humans are taking an active role in evolution both biologically and socially, having the effect of altering natural selection, perhaps even halting it.  Evolution, as proposed by Darwin, is a combination of heritability, random variation of genes and natural selection; the later two which Darwin formulated.  Evolution involves the appearance of a trait due to a random genetic mutation which can be selected for and thrive in the environment, or which can be chosen against and accordingly eliminated.  However, in Western society we are effectively taking control of our evolution through new biological and medical discoveries that can, among other things, extend one’s life and prevent possible extinction from undesirable traits or illness.  In addition, survival and reproduction in our society no longer depend entirely on genes and biological traits.  Social traits are often able to override seemingly negative biological traits and allow for the reproduction of that individual and their genes.  When these biological and social selection traits are combined, individuals and genes often survive that would not have, had these safeguards been eliminated.  This has the effect of increasing these genes and traits in the population and allowing for a larger population.  There are many positive and negative side effects that will be associated with this control of traits, one of them being that the effects of natural selection are being overridden. 

In western society we have taken our health and our biology into our own hands.  We are able to treat many illnesses that once plagued humanity, and if we cannot treat illnesses we have preventative measures against them including vaccines for bacteria that are microscopic.  We have mapped the entire genome and are able to match for certain genes, predict the genotype of our children and are on the verge of being able to utilize stem cells.  Our situation is very different now then it was when Homo sapiens first evolved.  At that time there was no medical treatment at all; evolution had a much larger role in society.  If an individual was born with a trait that was not beneficial to their surrounding, they would not be able to compensate or treat it and it may have caused their extinction, depending on severity.  For example, nearsightedness, a very treatable condition today, would be a very bad trait for our early relative as this individual would not be able to spot possible predators or dangerous situations and could not avoid death or serious injuries in these situations.  Individual with traits such as these would not be chosen for and their genes would not be passed on to their offspring.  Humans at this time were also not well suited to treat injuries when they did occur, an incision or broken limb could be the death of an individual.  In our society injuries such as these are no challenge to medical professions.  Accordingly, if individuals are born with negative or non beneficial genes these problems can be treated and natural selection, as survival of the fittest will not occur.  If one wants a modern example of how our relatives lived, one only has to look toward developing countries.  In contrast to western society, medical treatment is limited and natural selection is allowed to play a larger role.  The individuals in these countries do not have the technology or funds to compensate or treat the effects of an ill suited gene; their situation is very much like that of early humans.   

Our control of our biology and our heath is having many side effects on our species and our survival.  We are living much longer and this has many implications, not only for our species but also our economy.  Peter Ward of the University of Wisconsin theorizes that not only will people live longer, they will have many more children, effecting evolution in its own right.  He also states they will also have a longer time to accumulate wealth, thus also inadvertently affecting the economy.(2) Not only will people be living longer, we will be able to select for specific genes, even now we are able to choose the sex of our children.(3)  Given the example of our current biological technologies, it will be possible that all aspects of biological evolution and change will be in the hand of western scientists and their customers.  

This control of biological traits is not something that one must look to the future to imagine, maybe people are being selected for today than that would not have been selected for at the dawn of human life.  In fact, for several decades we have been able to choose for individuals and genes that nature would not have selected in the survival of the fittest.  For example, many individuals have vision problems; these individuals have been chosen for since the invention of eyeglasses.  Individuals who have congenital illness or diseases are being chosen for and their genes are being passed on even though this probably would not be the case if left entire up to nature without the intervention of science.  Similarly, aspects of our biology that would have been chosen for are considered less important and someday may be eliminated, such as the pancreas.  However, as important as it is that we are finding treatments for many medical and biological problems, it is important to draw the distinction between a cure, a treatment and prevention.  Through treatment and prevention we are not eliminating the gene that causes the weakness as may have been the case if left entirely to the process of natural selection.  When we are treating an illness or disease we are not wiping those weak genes out, in fact we are allowing them to continue to be passed on.  Effectively, we are choosing for these genes by allowing the individual to be treated.  The same is true for prevention, we maybe able to stop this phenotype from revealing it self but we are not eliminating the problem in the genome.  Treatment and prevention are positive for the affected person, however they are affecting natural selection and the effects that would be seen from it if allowed to occur unimpeded. 

Evolution and its effects are not only being manipulated through biological means but also though social effects.  Social effects and traits may have just as strong of an effect on evolution as modern medicine.  In western society, if you have an undesirable trait that you inherited through your genes, it is possible to effectively “override” this gene through desirable social traits.  In this same way, an individual my override nature selection by having beneficial biological genes, but because of undesirable social traits they may be unable to find a mate.  One biological trait that was once important that is no longer needed is hairiness, or an excessive amount of body hair.  When early Homo sapiens were living out doors and braving the conditions, hairiness was a desirable trait (especially in the more northern areas) and it provided warmth and protection.  Now hairiness is not such an important trait and may even be an undesirable trait in a potential mate.  However, if an individual with the hairiness gene is able to develop other socially desirable traits, they may effectively be able to reproduce and pass on this gene that would not have been chosen for.  This ability to over ride biology and the effects of natural selection through social traits was not as prevalent in the development of early Homo sapiens.  Although the passing on of social desirable traits was important, it was in no way able to override biology as easily as it can now.  If one was a developing human being living in the northern latitudes and was not hairy, no amount of social grace could save you from freezing to death in the winter.  It is important to note, again, that individuals living in developing societies are in the same position as these early humans.  In these environments conditions are such that biological traits for survival must be in place before social traits have their effect.            

The development of social traits plays such a large part in evolution that in some cases natural selection and survival of our species no longer depends on genes. (1)  These social traits include culture, religion and family tradition.  A cultural example of this explored by Gregory Cochran and Henry Harpending involves the natural selection of Ashkenazi Jews and intelligence over the past1000 years.  These individuals score 12-15 points above average on intelligence tests, a significant difference.  Cochran and Harpending point out that from 800AD to 1700 these individuals were restricted to working in fields that involved intellectual pursuits.  The most successful of these individuals passed on their genes to their offspring and thus created natural selection for intelligence.Those in this culture who were not suited for intellectual work were disadvantaged, were less successful and had fewer children.(1)  These social traits that affect natural selection are not simply passed on through society.  These traits are also created and furthered by individuals in society.  These individuals include the offspring’s parents, professors, peers and other individuals in their life.  As humans the social traits that we value, teach, and pass on have the ability to override natural selection and chose for individuals that nature would not have selected.    

Through biological and social means, human beings are overriding natural selection and selecting for individuals that nature would not have chose based on gene composition.  We are able to treat and prevent illnesses allowing individuals to reproduce, meanwhile passing on non beneficial genes.  Social traits are having an even stronger effect on natural selection by allowing individuals to be able to successfully find a mate and reproduce even though they may have some undesirable biological trait.  In the same way, a negative social trait may override an individual’s beneficial biological trait, preventing them from finding a mate.  Most of the ways in which we are overriding natural selection allows for the survival of more individuals, we are effectively allowing the “weak” individuals in our society to thrive and pass on their undesirable traits.   In western society we are perpetuating the survival of “weak types” of individuals. This may eventually have an effect on our environment in several ways.  Will our species become more socially adapted rather than biologically adopted?  Will this make a species that is biologically weak and maladapted?  However, how can we recognize the effects of our “human natural selection” without edging on eugenic and the ethics of medical treatment?  Perhaps, this is the next step in evolution.    Perhaps, when human beings were first evolving nature knew what was best for the survival of the species; perhaps this control has now been place in the command of human beings.  When a species becomes so socially or biologically advanced that they are able to regulate their own natural selection, perhaps natural selection it self has evolved and now is in the hands of that species.  

Works Cited:

1) “Are We Still Evolving” http://www.newscientist.com/channel/being-human/mg18925421.300-are-we-still-evolving.html 

2) “Is Human Evolution Finally Over?” http://observer.guardian.co.uk/international/story/0,6903,644002,00.html

3) “Second Opinion; Girl or Boy? As Fertility Technology Advances, So Does an Ethical Debate”

http://query.nytimes.com/gst/fullpage.html?sec=health&res=9C04E5DA133FF935A35751C0A9619C8B63

4) Serendip 

5) Mayr, Ernst. What Evolution Is. Basic Books, NY: 2001

Comments

taylor howard's picture

Boy do I have a book for

Boy do I have a book for you.. Perhaps you've read it. "Ishmael", author Daniel Quinn. Great eye opener for those who love this debate.

Paul Grobstein's picture

Controlling natural selection, now/ever?

The relation between evolution and human culture is indeed a fascinating one and one we'll be spending more time on in the course. Has "natural selection now evolved" so that "control has now been placed in the hands of human beings"? Does that constitute a "next step in evolution"? Clearly we and our culture has become a significant influence on evolution, both our own and that of other organisms. My sense though is that, the examples you cite notwithstanding, we are far from yet being able to "regulate" our own natural selection, to say nothing of that of other organisms. The issue here is partly one of existing actualities (cf http://serendip.brynmawr.edu/exchange/node/164 and http://serendip.brynmawr.edu/exchange/node/175 and http://serendip.brynmawr.edu/exchange/node/185 and http://serendip.brynmawr.edu/exchange/node/159), and my thoughts on those). But it is also one of whether it is in fact possible for any organism (ourselves included) to control a process that gave rise to it and other interdependent organisms through random events and continues to operate on that interdependent complexity in somewhat random ways. It is certainly true that "social traits affect natural selection" but those are themselves products of natural selection and necessarily interact with other kinds of traits in continuing exploration and selection. It doesn't seem to me appropriate, under the circumstances to oppose "social" and "biological" traits ("social traits" can promote reproduction even though the individual have "some undesirable biological traits"). Yes, what is selected for may change because of culture but evolution doesn't distinguish between "social" and "biological" traits, and we probably shouldn't either. Evolution, I would argue, has the same role before and after the development of "medical treatment". All that did, somewhat unpredictably, was to change what was selected for.

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