Natural and Unnatural History IV

I’m traveling in the Galapagos currently.  Hopefully I’m having fun and seeing great birds and other species!  In the meantime here’s a little of what I will hopefully be seeing!

The Galapagos’s Natural and Unnatural History: Evolution By Natural Selection

No series of vignettes showcasing the Galapagos would be complete without a thorough discussion of Evolution by Natural Selection.  Evolution by Natural Selection, from here forward will be referred to simply as evolution, is the process by which the representation of genes within a population changes over time.  I’m fairly certain that’s pretty close to word perfect the definition I used in graduate classes, but quite a headache to puzzle out for everyone else.

There is an amazing parallel in the behaviors of individuals and genes explored by Richard Dawkin’s in The Selfish Gene.   Individuals compete for resources in order to reproduce.   Individuals who reproduce, or reproduce more, are represented by future generations.  Imagine the typical high school romance movie plot where the main character attempts to woo away the popular girl from the popular boy a la Can’t Hardly Wait or Mean Girls.  In the main character’s ideal world, he and she reproduce.  Thus, whatever their genes are, are represented in their children.  Now, continue and imagine the rejected suitor pines away forever and never reproduces.  No matter how wonder his/her genes are, they will be lost from future generations forever.

Now, in most cases, for every athlete that is thrown over for a chess enthusiast, there is a chess captain who is rejected in favor of a team captain.  Everyone pairs up with someone, and the genes are equally represented from one generation to the next.  When you have strong selection events, say all athletes being removed from the gene pool, then the representation in genes for the subsequent generation will be different.  That is evolution (by natural selection).  Even if it only happens for one generation and athletes come back into vogue the following generation. (Cause let’s face it, there are some out there who may be both ardent chess and sport participants keeping the genes alive).  But, if it happens for generations following generations and you have a sustained, directional push favoring chess players over athletes, the ratio of chess players to athletes will diminish and athletes could be lost entirely from the population.  Imagine that.

As individuals select mates for reproduction, the genes get carried along.  Sometimes the selection is intentional.  Deer selecting for large bucks with lots of points let’s say or cardinals choosing for the brighter red feathers; sometimes the genes aren’t as obvious, but nevertheless they’re carried along into future generations.    It’s the whole package that made the individual desirable (even if there are some poor genes in there). However, through reproduction, the genes get all jumbled up and the offspring are not replicates of their parents.  Hopefully, they’re better.  Because through the union, the hope is the best genes will find representation in the offspring.  Thus, the children will be more “fit”, than the parents.

This is remarkably relevant for a number of reasons.  First, many credit Darwin’s  visit to the Galapagos with setting him on the path that led him to his theory. Second, the Galapagos is a top notch destination for studying evolution in action.  Third, some really awesome aspects of evolution happened in the Galapagos, and is still happening!  So stay tuned.

Additional Reading:

  • The Selfish Gene. Richard Dawkins. 1976.