Happy Thanksgiving. If you are participating in the Black Friday festivities, I hope you avoid being tased, pepper sprayed, punched, trampled, or any variety of associated violence. In keeping with the Thanksgiving spirit, I thought I would write a post about being thankful. This holiday season, let's all be thankful simply for our existence...
What was Charles Darwin’s primary contribution to science? If you answered “evolution,” slap yourself in the face.
Just kidding. Don’t. But truthfully, Charles Darwin did not come up with the idea of evolution. He explained it. He came up with natural selection. That was his major contribution to science.
People began to connect the fossil dots long before Darwin came along. In fact, there was sort of a natural history craze that was happening (especially in England. Gotta love those crazy Brits). They noticed that similar fossils seemed to gradually change over the strata. The evolution wheels had already started to turn in the years before Darwin. Naturalists unarguably recognized that species gradually changed over time, but had no foggy idea as to the mechanism that produced this gradual change.
Enter Charles Darwin. He proposed the idea that certain traits may give animals a survival and therefore reproductive advantage over others. These animals are statistically more likely to score and have babies. Those babies are then more likely to also carry the advantageous trait from their mom or dad (or both). And here is evolution on the smallest scale- a genetic change between generations. It carries on down the line until the changes become so drastic that a new species is born. This is speciation via natural selection.
Okay, to be honest, I just made it sound way simpler than it is. Not all traits that evolve are necessarily “selected for.” Sometimes they are random, sort of meaningless characteristics. Take human eye color, for instance. There are hazels, browns, blues, and greens. These colors evolved, certainly. But were they selected for? Did having blue eyes make somebody more likely to have fit offspring over brown eyed people? Probably not. Random, chance mutations caused these diverging eye colors. Not selective pressure.
There in lies a nuance of evolutionary theory that often goes overlooked. Evolution is not intelligent nor guided (sorry, pro-intelligent design homies). Nor is it a perfect process (queue dancing appendix here). Some things evolve purely by random chance, and natural selection acts upon only the traits that make a critter more likely to have fit offspring. All life is a result of the interaction between random chance and natural selection.
Eye color. Jellyfish. Strep throat. Poison ivy. You. These are all things that are here thanks in large part to chance. We earthlings are a lucky bunch, aren’t we?
I accept the theory of natural selection. It's been talked about in nearly all of my classes since day 1. However, here's an interesting thought. I can't claim it is my own but it's something the author of Dilbert (can't remember his name) pointed out.
ReplyDeleteLet's pretend that some bacteria on some asteroid that struck earth wiped out the human race. And eventually some alien scientists discovered earth and tried to figure out what went on there. They'd find our cookwares and notice that they were all related. They could see that the old bowls made of clay and stone evolved into the new ones out of porcelain. That they then eventually turned into coffee pots and large pots. Or a plate turned into a frying pan. They could put all the tea cups into a family and say they are close relatives to the coffee mug and water cup. Anyone could look at these charts and see that this pattern was no coincedence! Any contradictory theory would be mocked due to the volumes of evidence they could collect. Good thought eh?
True, but with species it's a bit different. We can now use DNA to show that one animal has a lot of common "ingredients" like another animal. Then, knowing what we do about how DNA is passed on etc. we are able to see that the animal must have come from the same lineage. There's more to it than simply looking at physical similarities.
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