What is Natural Selection?

Biological anthropology is the broadest of the four subfields of anthropology, and it is the field that is most concerned with the biological evolution of the human species.  One of the underlying concepts of evolution is the concept of natural selection, which Charles Darwin put forward in his pivotal publication, The Origin of Species.  You may have heard of this concept, but do you really know what it means?  This blog post will explore what specifically natural selection is and its effect on evolution.

Before we jump into what natural selection is it is important to discuss what it is not.  It’s not some being, such as Mother Nature, choosing who lives and who dies.  It’s not even individuals deciding who will live and dies.  This could be artificial selection, the deliberate breeding of species. 

Natural selection is random, but it’s based on a series of natural factors that unknowingly select individuals within a species that are considered best to survive.  This selection is based on our individual genetics, or the genes we possess.  As previously discussed we are made up of DNA and genes.  Our DNA acts as a blueprint, which determines what we will be, but our genes act as the parts that make up the whole.  Our genes do and will vary, which is why some people have blue eyes and others do not, and it is this variation in our genetics that leads to what nature selects for.  But how exactly does this work?  Well, it is our genes that make us or break us so to speak when it comes to survival, but as noted in the previous paragraph it’s the nature that selects, so to speak, which genes are better for survival than others.  Nature is made up of environmental and biological factors, and we will address each, starting with the environmental factors. 

Environmental factors can be broken down into physical, biological, and cultural environments.  Physical environments are made up of the inorganic, nonliving elements of the environment, such as the sunlight and rocks.  The biological environment includes all living things that exist in the environment, such as the creatures and plants.  The cultural environment is the manmade materials that exist in the environment, such as shelter, air conditioners/heaters, and clothing.  All of these factors play a role in evolution because they make up the scene that makes it either more or less beneficial to have specific genes.  For example, if an organism is lighter furred or skinned and can better blend in with its environment then it has beneficial traits, whereas any organism with nonmatching fur or skin color is disadvantaged by the environment it lives in.  The biological environment also plays a role because, as the popular saying about the zombie apocalypse goes, you need only out run or outsmart your opponent to survive.  If you cannot out compete or compete with your biological environment, specifically against predators, you won’t live very long.  Lastly, the cultural environment is also a factor because what you lack in genes you can make up with cultural innovations, which is why birds that may not be the best at getting worms can still survive if there is a bird feeder nearby. 

Biological factors also play a role, too.  When we discuss biological factors we mean one’s ability to breed.  It doesn’t do a species as a whole any good if their best, brightest, most survivable do not pass those genes on to the next generation.  See, with natural selection it is less about the individual and more about the species as a whole.  If an entire species has traits that make it survivable that’s what we, scholars, are concerned about.  If an individual has traits that are more beneficial then for the species to survive that individual must pass on his or her traits to assist the species to survive.  There have been quite a few movies based on this premise, which originated from natural selection.

So there you have it.  When we discuss natural selection we are referring to the random chance that the genes you have are what will assist you in surviving.  You have to be able to survive in your physical, biological, and cultural environment and pass those traits on to your children, or the next generation.  For those who need a review or a visual check out this awesome video (that I did not make) that provides more details on this topic.

References

Jurmain, Robert, Kilgore, Lynn, Trevathan, Wenda, Ciochon, Russell L. Introduction to Physical

Anthropology. Belmont, California: Wadsworth, 2014. Print.