Thankfully, most of the people I know accept that microevolution* is present in the world all around us. (I’m not really sure how people who don’t believe in microevolution explain drug-resistant bacteria and etc – perhaps witchcraft? I’ve never had the pleasure of discussing evolution with such a person.)
However, they still are not convinced about macroevolution. It can be hard for someone versed in evolution/biology to understand why someone could accept one and not the other, as this quote reflects:
Saying you believe in microevolution, but not macroevolution, is like saying you believe atoms exist but that you don’t believe you’re made out of them simply because you don’t see how something so small can be a part of something so much larger.
- (Credit to Patrick Hunter, in an evolution group on Facebook)
While the quote is humorous, and pretty true in my opinion, I believe there are two main reasons for why people balk at macroevolution:
1. Understanding ‘Species’ – There is a huge amount of controversy in the defining of what makes a ‘species,’ and how to differentiate species. Most people tend to take the species rules commonly used that they know at face value, without really questioning how obviously incomplete they are. We have classified animals as different species based on tiny differences in colouration, shape, or size, even when they can produce viable and fertile offspring. Yet they’re on different sides of a mountain, and don’t meet, and so don’t breed in nature, so we call them different species. Well, hey, before the Portuguese discovered Australia, Europeans certainly looked different from aborigines, and certainly didn’t interbreed. Different species? Of course we can’t say that, since it’s not politically correct – but it’s a good example of where our species rules have gotten us. Not to say that they aren’t damn good rules – it’s just that it’s hard to draw a line where there almost isn’t one (hint hint). Species are in the eyes of humans ONLY.
So, forgetting this, people tend to think of macroevolution in the largest possible terms – amoeba to fish, or multi-celled creature to man. When, really, if you can accept that a few changes in size, colour, and shape can stop some specimens from back-breeding with those who don’t have the changes, you have the foundation of macroevolution. Now it’s not far to see the mutations that accumulated to differentiate a King penguin from a Galapagos penguin. And from there, it’s not hard to see how penguins differentiated from sea-going (swimming) birds, and sea-going birds from land-going birds. Follow that on up, and you’re well on your way.
2. People Don’t Understand Genetics – Many people tell me they can’t accept macroevolution because ‘it just doesn’t make sense to me.’ To really understand evolution, one must understand genes. And mutation. And alleles. And frequency of alleles. And ‘fitness.’ And ‘relative fitness.’ And change in frequency of alleles. And natural selection. And heritability. Obviously, that’s a lot to ask, and a lot to learn, especially if your biology understanding is basic. Once you can get a picture of all of this in your head, evolution clears up quite a bit – better understanding the behaviour of genes alone (never mind really understanding what ‘fitness’ means) can make a huge difference in someone’s comprehension level of evolution.
But part of me wants to say that this isn’t really an excuse. Can we/should we believe what we don’t fully understand? In an ideal world the answer is no. But hey, this is reality. We believe things we don’t understand all the time. I don’t fully understand why really big things attract other things (gravity), but I believe it’s true – and I doubt anyone’s going to call me gullible for doing so. On the other hand, I don’t want to tell people to just ‘trust’ what I say when I tell them that evolution is real because I’m a biologist and I understand it. But, back to the other side, can ignorance really be claimed as a reason not to believe something? ‘I don’t understand it thus it can’t be true?’ If I really questioned the validity of gravity, I’d go out and try and find out more. I don’t think it’s asking too much for those who don’t believe in evolution to go learn some basic information so that they can better understand what ‘doesn’t make sense to them.’
I guess I do like the quote at the top more than I admitted at first. It’s true – just because you yourself can’t see how something fits in to the big picture doesn’t mean it isn’t the truth anyway. Even if it’s incredibly hard to picture (can you truly wrap your mind around the fact you’re made of itty-bitty tiny atoms whose properties are nothing like you?), it far from means it’s impossible.
So go out there, guys, and Viva la Evolution!
*I know these terms (microevolution/macroevolution) have some controversy about what they *exactly* mean, especially in the argument’s context, but whatever.