I thought I'd take time away from my baby-blogging to do a post on evolution. It's a pretty cool theory (by theory, I of course mean absolutely true facts that are uncontested by people who know their science stuff).
Every living thing on Earth is part of the same family: the germs in your body, the grass on your lawn, George Bush, everything. Creatures that are the most different from us (like the mold growing in the fridge) are distant cousins of ours, while primates (they have opposable thumbs, we have opposable thumbs, we're practically the same animal) are our closest relatives.
Natural selection is the part of evolution that explains why some traits get passed on and some don't. To explain: Say you have a family of monkeys that live in a jungle where there are ferocious beasts that want to eat them.
Bobo the monkey has flexible feet that make it a lot easier to climb trees, so he climbs the tree, has ten kids who can all climb trees too and they all live happily in the tree.
Al the monkey can't climb trees but he's super intelligent and can outwit all the beasties, he also has ten brainy kids.
Bo the monkey can run really fast, but he can only carry two baby monkeys while he runs, so only 2 of his kids live.
Dumbo the monkey is an idiotic slowpoke who can't climb trees. He does have a big wart on his left foot, but that doesn't help so Dumbo gets eaten before he can have any kids. Not all mutations are useful, you see.
Meanwhile, the beasties eat all the Dumbos, and some of the Bo-offspring. But they're still hungry. Some of them learn to climb trees, some of them get smart enough to catch Al and his family, some of them start running as fast as Bo. In other words, the monkeys evolve to get away from the beasties, and the beasties evolve to catch the monkeys. Keeping in mind that the beasties and the monkeys (and the trees) are cousins.
Now you might be thinking, but Jen, we shouldn't eat our cousins! Unfortunately we need to eat at least some living things to survive (bummer), but as highly evolved Al-monkeys we've developed many different philosophies to help us deal with the squimishness of having to eat our cousins:
Some people have decided that they'll only eat our very distant relatives, no mammals, no birds, and in some cases, no fish. They have eyes, we have eyes, they're practically human.
Some people have opted to pretend that plants and animals aren't our family members at all, and have instead invented elaborate mythology about Earth and humans being the centre of the universe.
Some people (and this is my personal favourite) get other people to kill and harvest our cousins for us, so they come in fancy packaging, with eyes removed, and they don't look very alive anymore.
Despite the required gruesomeness, I'm glad we're all related. I think our family is pretty darn amazing, don't you?