This page will deal with biological evolution, one of my favorite facts about the universe and, once properly understood, is a candidate for the most amazing fact you will ever be called upon to contemplate in your whole life.
So where is a good place to start? Well, let’s start in the same place the ancients did; Where does complexity in nature (in the form of living organisms) come from?
The answer is simple to summarize and beautifully elegant in its explanatory power: evolution by natural selection. It shall have to suffice to give a brief explication of this process in this post (I want to save some of the details for later posts). It turns out that the basics of evolution can be easily and simply summarized in four self-evident premises:
- Heredity – Every organism gets traits from it’s parents. It is no accident that we tend to look more like our parents than our neighbor’s parents.
- Variability – While we get our traits from our parents, we don’t have exact copies of their DNA. We get a mixture (plus some minor random mutations) that results in variation. That’s why we don’t look exactly like our parents.
- Exponential growth of populations – If not restricted, any reproducing species would spawn enough offspring to cover the face of the globe in a surprisingly short amount of time. Exponential population growth goes something like this, assuming only two children per family: 2×2=4×2=8×2=16×2=32×2=64…
- Limited resources – Because of the limited supply of food and other resources on the planet, organisms that can compete the best for it will have more offspring than their competitors. If I can beat you to the food or reach food that you can’t, I’m more likely to survive longer than you and thus have more offspring, passing on those genes that made me successful.
Even the most dyed-in-the-wool creationists can’t seriously doubt the transparency of these premises and yet it seems to necessarily follow that, given enough time, this process could account for all of the complexity we see in nature. It has been understood for millennia that organisms change over time – domesticating animals taught us that. Professional dog breeders have turned close cousins of the wolf into everything from Great Danes to Yorkshire Terriers (and, of course, Puggles!) in just a few short centuries.
The realization that Charles Darwin had was that you didn’t need people to be the selecting agent, the thing that decides who breeds and who doesn’t. Nature, in too many ways to list, can unconsciously be the selecting agent. Evolution is probably the worst optimizing process in nature, but it works. And it does so without brain power, foresight, or intelligence. That is what makes it amazing, and it is the strange inversion of reason that makes it difficult for many non-scientifically minded people to get their heads around it.
I plan to go into much more detail later, but this page has been almost blank for way too long.