Monday, August 17, 2009

College For Free 6: Human Evolution

I am aware that there are some poor souls out there in the world who still don't believe in evolution, and think that God just plopped us all down here as is. I think that if you were to make a Venn diagram of people who believe that and people who have no college education, it would look like a circle. In short, I think there is a good reason that 99% of all scientists are atheists. But as easy as it is to takes shots at religion, that's not why we're here today. Today, we take a look at human evolution. The most important thing to keep in mind here, and the reason I think this is worth discussing, is that evolution is pretty complicated stuff, and the evolution of humans is a lot more diverse than most people realize.
First, I think I should clarify this whole "evolved from monkeys" business. A common argument against the theory of evolution is that if we evolved from chimpanzees, then why are there still chimpanzees in the world? While this may seem like a valid argument at first, any kind of actual research or education on the topic will reveal it to be completely ridiculous. First of all, while human DNA and that of a chimp is 99% the same, we did not evolve from chimpanzees, or any other monkey/ape as they exist on the planet today. Humans and chimpanzees have a common ancestor, one that we probably shared 7-10 million years ago. This would have been a single species that became both humans and chimpanzees as it evolved along two separate paths.
This is like how you can't say that that Tool evolved from The Pixies, but without The Beatles we probably wouldn't have either of them.
Something I would like to mention here is that the first hominids were all from Africa, appearing there maybe as long as 15-12 million years ago. I have always thought that this was interesting, because it does a weird thing to the term "African American." To me, African American is an inherently racist thing to say, because you are assuming that if someone is black, they are from Africa. Why couldn't they be from Jamaica or Haiti or the Middle East? The argument, I believe, is that even if the person's ancestry traces them back to one of these places, it is assumed that before their ancestors were anywhere else, they were in Africa. And that's true, but it's true because it's true of everyone. All human life began in Africa, according to current scientific knowledge, and we all spread out from there.

The Australopithecus Afarensis (4-3 million years ago)

You may have heard of the quasi-famous fossil found of this ancient relative of mankind. Her name is Lucy, and she is the oldest ancestor of our species ever to be uncovered. Not surprisingly, Lucy is a good deal smaller than today's Anatomically Modern Humans (which is what we are.) The size of her brain is also a good deal smaller, which flew in the face of predictions made about early hominids before Lucy was discovered. It was originally theorized that early hominids would have evolved large brains while still looking a great deal like monkeys, but it turns out brain size was just about the last thing to change. As the process of evolution progresses, we see that the body remains very similar while the head undergoes most of the major changes. Lucy is also a biped.
I don't know if you've ever thought about it, but we are the only mammal on the planet to ever do two things: 1. We put a man on the moon. 2. We walk on two legs. Somehow, the two are directly related.
In evolution, small differences go a long way. Any slight advantage will pay off in the end. As my teacher put it: casinos only have a 51% chance of winning while an individual gambler has a 49% chance. Even though these odds are almost completely even, that 1% will insure that if you walk into a casino with a thousand dollars and proceed to gamble continuously, even if you win big a few times, the casino will eventually have all of your money. So it goes with evolution. Bipedalism is a more endurant form of transportation, and so it allowed us not only to walk for very long distances, but also to carry things with us for those long distances. It also helped us to see over tall grasses, which I suppose would be helpful for spotting predators.
Gracile and Robust Australopithecus (3-2.5 million years ago.)
It's useful to talk about these two species of humans for one reason: one of them didn't make the cut. While both of these species evolved from Lucy's generation, only Graciles would live on to evolve again, for whatever reason. This is notable because I think people tend to oversimplify when it comes to evolution. That's where this whole "we evolved from monkeys" logic comes from. We have a hard time imagining the complexity of millions of years of evolution, so we see things as a much straighter line than is realistic. Robusts get their name from the large jaws they developed from eating tougher foods,which is the only difference between them and Graciles, and yet they did not make it.
Homo Habilis (2.5-2 million years ago)
These were the first guys to make any form of tools. Known as olduwan choppers, these tools were basically just sharp rocks that Homo Habilis used to scrape the meat from bones. They had to do this because, as the fleshy, slow, harmless kind of species that we were and still are in comparison to things like lions and crocodiles, we were scavengers at this point in history. At about fourth or fifth in line after all the bigger animals to scavenge an animal carcass, Habilis had to come up with some way to get a satisfactory amount of meat. They used their tools to scrape the meat out from between the bones, you know, like that little sliver of meat left between the two bones in the kind of chicken wing that nobody wants. Why do they even make those? They should all just be chicken legs, if you ask me.
Homo Erectus (2 - 0.5 million years ago)
Hey, we're finally out of Africa. Homo Erectus are the first to leave, some going northeast towards Asia and some going northwest towards Europe. In this group the tools are becoming more advanced, though they're still using the rocks inefficiently by using the core instead of the smaller pieces that break off. In other words, they're ignoring the fact that they can break off one piece and use it as an arrow head, and are instead breaking off tons of pieces in order to shape the rock into an ax.
Neandertals (200 - 30 thousand years ago)
Yes, I spelled it right, there's no "h." Neandertals, like Robust Australopithecus, did not make the final cut into the human gene pool. We did not evolve from them, they were a separate species that died out 30 thousand years ago. They were a cold adapted people who lived in Europe and even as far south as the Middle East. Cold adapted means that they were short, stocky, and had wider noses to breathe the frozen air. Unlike the cartoony portrayals of cavemen that we most often see, they were not stupid. This was the first group of hominids to intentionally bury their dead, going as far as to lay flowers on the graves. My teacher said that, in his opinion, if you were to take a Neandertal child from 200 thousand years ago and put him into modern day schools, that he would probably do just as well as the average child and be just fine.
Archaic Homo Sapiens/Anatomically Modern Humans (500 thousand years ago -Now)
One hears, every now and then, about the exponential growth of technology. Just think about how quickly we went from listening to vinyl records to mp3 files. Think about how quickly we went from the first plane in flight to the first rocket into space. Once technology gets rolling, it really gets rolling, and right now we're looking at a time period when "technology" was a sharp rock. It took our ancestors over two million years to figure out that instead of making a rock into one big tool, they could save themselves a whole lot of time by making it into a dozen smaller, more effective tools in the forms of spearheads and arrowheads. It's only in the last 500 thousand years that we developed language, communities, art, farming, politics, religion, the wheel, boats, electricity, cars, guitars, guns, roller coasters, nuclear power plants, and Play-Doh. Not bad for a pretty new species, I'd say.

It strikes me, though, that everyone sort of thinks this whole evolution thing is done. This idea of an evolutionary peak, or the permanence of this particular sliver of infinity in which we exist, is a symptom of a society that doesn't even attempt to integrate big-picture ideas like time and space into lower-level education. In American schools, history class seems to insinuate that time began with the Revolutionary War, and American history is the only one that matters. Everything that happened before the 1700s is left to guess work, and guess work leads to these conclusions about evolution from monkeys and Neandertals. It also keeps history seeming small, and helps keep time a comfortable thought. Some stuff happened, some stuff is happening now, end of story.
When you really look at it, however, time is a flowing thing, a thing that we have entered into and will one day exit. The universe is not a stagnant thing, but something we are participating in, and in that way human evolution and progression are still relevant and still exist, even if not physically.
That's why I don't understand conservative politics, this idea that the past was the right way, and that we must stick to the morals of the past. If we all thought like that, we'd still be scraping the meat out from between the bones of over-sized chicken wings in Africa.
Evolution is no longer about physical prowess.
It's time to evolve ideas.

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