Question from Erica:
If evolution exists wouldn’t it still be going on today? Wouldn’t every animal species be evolving into humans since we are at the top of the food chain?
Answer by SmartLX:
Even if they were all doing that, it would be so gradual that you probably wouldn’t notice. You might be able to look at ancient paintings of animals and remark that today’s animals looked a teensy-weensy bit more humanoid, but you wouldn’t see any significant changes in the space of your own lifetime.
Evolution has no objective. It doesn’t try to push everything to the top of the food chain, or make every animal more intelligent. Evolution itself has no intelligence, because it is not an entity with any sort of will; it’s an emergent process resulting from the non-random selection of random mutations. In lieu of objectives it does have effects, such as increases in biological complexity (in nearly all cases) and improved survival and procreation mechanisms in persistent populations.
For humans and their immediate ancestors, becoming more able to survive did mean standing upright, growing smarter and using tools. For cheetahs, it meant growing faster, and therefore it meant the same thing for antelopes and gazelles. (Of the five fastest land animals in the world, two hunt the other three.) For some dogs and cats it meant becoming more “personable”, facilitating beneficial relationships with humans (though once that happened, humans began applying artificial selection to both animals). For a tree, it may simply mean growing taller, or poisoning the animals that try to eat its leaves.
Some species have pretty much given up on surviving reliably as individuals and put all their biological resources into procreation instead. Insects and rabbits breed like wildfire, so that even if most of them are killed some will remain. Grass grows back even if nearly all of it is eaten, poisoned or pulled up. And of course, some species have developed great methods of both surviving and procreating.
You’ll have heard the expression “survival of the fittest”. It means that those life forms that are best adapted to (or “fit for”) their surroundings will likely survive and pass on their genes to the most offspring. That suitability for staying alive long enough to reproduce is ultimately the only metric that matters in evolution. The advantages of being human are only one way of many to achieve that condition, so there’s no pressure on animals that get along perfectly well being different from us to become more like us.
Evolution is indeed going on today, slowly but surely. Just not like that.
Question from Erica: