The meaning of the word

I guess that before I start telling tales, I should make sure people understand what I'm talking about.  Like any field, biology is full of jargon - specialized terms used to describe what's going on.  Biologists spend an inordinate amount of time debating what those words actually mean.  So here's my disclaimer:  any jargon I attempt to define in this blog is my own interpretation of what a particular word or phrase means.  There may exist alternative interpretations.  I'm not a lawyer, I'm a biologist.

So let's start with the obvious - evolution.  Simply put, evolution is change over time in the DNA of a population of interbreeding individuals.  I tend to favor talking about evolution in terms of changes at the DNA level, because I'm a molecular evolutionary biologist, and I think it's easier to understand that way.  Now there are a couple things that evolution is NOT.  

Evolution is NOT:

- directed.  There is no goal, no plan.  Evolution is like taking a random walk without a map.  You don't know where you're going and you might have a faint idea of where you came from.

- progressive.  All organisms are equally advanced.  There are not higher plants and lower plants.  Flowering plants, because they are more recently derived, are not "better" than algae, which share a common ancestor with flowering plants.  It is only fair to describe things in terms of increasing complexity.  

So to me, if you say you don't believe in evolution - then what you're telling me is that you think that the DNA of every organism on this planet is the same as it was at the beginning of time.  Now, I ask you - do your children have the exact same DNA as you, with absolutely no changes?  If your answer is yes, well then I'm afraid males shouldn't exist in your world.  The basic idea behind evolution is random change in the genetic material that is passed from one generation to the next.

Now I think the only world people would disagree with in that statement is the word random.  If you think all change is directed and progressive, then you don't agree that the process is random.  I guess my challenge is to supply evidence for the random nature of evolution.

There are a lot of different processes that result in evolution, starting from the mechanisms of mutation and recombination to evolutionary forces such as natural selection and genetic drift.  So that's what I'll talk about in my next posts.