What topics do I cover?
I mean, I've got a lot of random things in my hat that I could write a short blog post about: decomposing bodies, DNA, human evolution, Neanderthals, the origins of art/fire/cooking/warfare, eugenics, human variation, racism, apes, skeletal anatomy, archaeology, the desert southwest prehistory, peopling of the new world, etc. (why yes, I have taught college lectures on all of those...that's what happens when you are an adjunct professor for a few years, lol!) Anyone want to chime in with what they'd maybe like to see?
Until I start getting these all set up, here's a post I did a while ago :)
Today, I thought I'd touch on one of the most basic principles I teach. And what might that be? Oh, just the introduction to Darwin and Natural Selection. Yay! Some of my favorite topics :) (Avert your eyes if you don't like this kind of stuff, or read on and realize how it really works!)
|Darwin. The man. The Legend.|
Where to start? There's so much! Darwin wrote ON THE ORIGIN OF SPECIES in 1859, after sitting on his research for decades. It wasn't until Alfred Russell Wallace contacted him, noting that he had similar conclusions, that Darwin got off his butt and published. (I'll admit, I have a penchant for all the crazy personal stories that go on behind the scenes for some of these theories--they are so interesting! Wallace is a fascinating character.)
Darwin's theory of Natural Selection is based on three basic principles that all have to be functioning for it to work:
- Over Reproduction.
- A species will reproduce exponentially. Their resources won't (like food). Eventually a species will hit the limit for their habitat, and unless they're able to come up with another source, there will individuals who don't survive. This creates competition. Thanks to Thomas Malthus for this idea.
- When environmental crunch time comes, there will be some individuals who do better than other because of some trait they carry. They will be the ones who survive over those who don't carry whatever trait it is. There has to be some variation, or those who survive will just be due to chance, and then no long-term changes will occur.
- Or inheritable. Nothing that is non-heritable is going to work--so a trait that someone picks up during their lifetime will not be passed along (unless it's teachable, or epigenetic...). No Lamarkian evolution here (or the inheritance of acquired characteristics, which really doesn't work)!
So, in a lot of writings, the thing that I see messed up the most is point #3. The trait that is passed down must be genetic (unless it's behavioral, and then it's a whole other ball of wax). All three points have to come into play if Natural Selection is going to work.
One last point on this massive post: Natural Selection is NOT the same thing as Evolution. Many people mess this up, because they are totally related, but NS is a form of evolution, but they are not equivalent. Evolution is simple change over time. It can occur through NS, or through a variety of other means, like sexual selection (a very interesting concept!). But they are not the same. Good thing to keep in mind!
So, what do you think? Helpful? Other things you'd like me to elaborate on? Shout it out in the comments!