I met one of those people who doesn’t believe in evolution again. I was a bit stunned, as for me not believing in evolution is like not believing in gravity. I’ve kind of taken to not even trying to explain it anymore, because there are only two reasons why people don’t believe in evolution and those are religion and ignorance (often both at the same time). Arguing with the first is pointless (as they can’t accept evolution since it is at complete odds with their faith) while argueing with the second is a waste of time, as anybody that says they don’t believe when really they don’t understand is really somebody I’d be better off avoiding.
Still, as you might well know I have a tendency to break my own rules (after all, everything I believe will probably be proven wrong at some point in the future) so here I’ll again try to explain the basics of evolution.
First off, evolution is something that works over a very, very, very, very long time. It does not happen in one life time, it doesn’t happen in ten life times, in fact it only happens in thousands of life times. That’s the point. Only when you have that kind of time can evolution take place. The reason for this is that evolution is all about miniscule changes that you barely perceive per generation. It was not that one generation there were monkeys and the next there were people. We are very, very distant relatives of monkeys (for one thing, they didn’t stop evolving either).
Consider a photocopying machine. Every time you make a copy, it is a little bit different from the generation before; a slightly different angle, a slightly different colour, etc. We are copies of our parents (a little bit from one, a little bit from the other) with a very, very small chance of mutations (no copy is ever perfect). The amount of mutations is really, really tiny – so tiny that none of our own copying mechanism compare. Still, it happens. These mutations are generally harmful and the unfortunate child doesn’t replicate, or replicates a great deal less than its generation mates; but on occasion there’s a helpful mutation (a little faster, a little stronger, a little smarter, a little bigger, you get the idea).
These mutations make the fortunate receiver a little fitter (remember that expression, survival of the fittest?) and as a result they get more than their generation mates and therefore are able to have more children than their generation mates. Those children that also get this mutation (not all them will, a little from the mother, a little from the father) will also be a little better than their fellows. As a result the mutation spreads, at the expense of the original, un-mutated version of the species.
Of course, the advantage is very small and therefore can take many thousands of generations to spread through the whole population. That’s why there’s different versions of the same species – especially if the two versions of the species were separated.
Which brings us to the next part of evolution – a new species is formed when two originally same species populations are somehow split (mountains, distance, rivers, what ever) and evolution is allowed to work on both independently. First off, not the same mutations will happen (mutations are random) and secondly, their environment might be different, which would mean different mutations would deliver different advantages (for instance, seeing far would be much more useful on the savannah than in the forest). Slowly these mutations accumulate, until the two original groups have changed so much they can't even mate with each other anymore.
So why can’t we find some in between monkey man? Well, in all probability because we’re an incredibly aggressive species and have long since eliminated the competition. Monkeys have evolved into their own niche, where we don’t feel greatly challenged, but any species that tries to occupy the same niche as we occupy (ground dwelling omnivores with a preference for the savannahs) will have to compete with us - Winner takes all. Apparently it was us that won.
Also, if we would have come into existence slowly all over the world, then there would probably be more versions of intelligent, upright walking creatures; but we only came out of one place, Africa. So there was really only space for once species, us. Of course, there was another species much like us, the Cro Magnon – but they all seem to have kicked the bucket as well.
Another mistakes is to think that evolution has stopped. It hasn’t. We are not the peak of evolution, we are not the end result that evolution was aiming for. All species that exist on this world today are equally as evolved as we are. Evolution has spent just as much time on them as it has on us. They just have different tools than us.
And don’t think that we’ve got the best tools, either. There might be a lot of us, but ultimately it isn’t about how many are around now, but about who sticks around the longest. We’ve been around for a very short time and at the rate we’re going, we won’t be around much longer. In fact, if you really want to know what is possibly the most ‘advanced’ on the planet (as in, it would survive the best what ever happens and is therefore the fittest) it would be the humble (and hated) cockroach.
Now I can tell you more, but I’ve already well overshot my normal length. Instead I advise you to read Richard Dawkins’ book ‘The Selfish Gene’ and if you’ve read that, that and still aren’t convinced by evolution, then we’ll talk.
PS: Please don’t let the fact that Richard Dawkins wrote the book ‘The God Delusion’ influence your decision to read ‘The Selfish Gene’. First off all, that book was written now and the Selfish Gene nearly twenty years ago; secondly it’s the message that matters, not the messenger.
PPS: 'The Selfish Gene' is possibly one of the best written books I've ever read, in case you're worried about that. I thoroughly enjoyed it and it really taught me a great deal. If I could write like Richard Dawkins, I'd be happy as a writer.