Thursday, July 2, 2009

But if humans evolved from apes, why are there still apes?

I hear this question frequently from people (especially creationists). The answer is actually pretty simple. A better question would be, "if humans evolved from fish, why are there still fish?" Fish don't have lungs, can't walk on land, can't fly and are slimy. Surely us modern mammals like humans, bats, and tigers are so much more advanced! Why haven't fish gone extinct?

The easy answer? Fish are still around for the same reason bicycles are still popular years after the invention of cars and rocket ships: they are configured for different environments. Sure, fish can't do some of the great things that humans and birds do, but the job they do (swimming), they do very well. A bicycle is no moon rocket, but it's a much better vehicle for a quick run through the city park--or crowded streets. Heck, even after all these years of bicycles and cars, policemen still oftentimes ride horses!

Creationists make hay over the occasional discovery of a "living fossil." Once in a while we find a living animal that we previously thought was extinct. Sometimes the living animal is very similar to million-year-old ancestors. But again, in the case of a fish (like the famous coelacanth), evolution long ago arrived at the best shape for living in the oceans. Why would we expect it to look different?

Explaining the persistence of perfectly functional animals like fish or apes is not at all difficult. Evolution adapts animals to their environments. As long as those environments are still around (oceans, deserts, forests, etc.), animals that are well-adapted to them have a shot at being around for a long time as well.

2 comments:

Tyler Fox said...

Hi,

Nice site and nice post. I came across this doing some online research for a teaching unit on evolution. I want to just make you aware of some ideas and terminology that have some big implications.
The first is using the phrase "evolved from." This is usually not correct, as two branches on a tree (take humans and apes) did not evolve from one or the other but rather from a common ancestor that may have been neither (human nor ape). This is important because many creationists take umbrage at the fact that we "came from" apes (and then they think of what they see today) when in fact we both have evolved since diverging long. long ago from an ancestor who was very, very different from either of us.
The second point is more or less related to the first, and it is on the matter of "advanced." You clearly demonstrate correct understanding of evolutionary theory by your description of how certain organisms are better *adapted to their environments. However, adaptation does not always look like our anthropocentric idea of "advanced." Every organism that exists today is just as advanced as the next by the simple fact that it exists: it is a form that is adapted to survive in its environment. By this measure, we are no more advanced than tigers, or even the slimy fish in the sea! Using the term adapted rather than advanced seems like a semantic quibble, but the implications again bear serious consequences for creationism because of the place it relegates the human race in the tree of life: not at the top, but on one branch among millions.
your fellow student,
Tyler Fox

David Board said...

Hi Tyler,

Thanks for the comments and the kind words. I definitely appreciate the points you make. However, I have a slightly different take on both issues.

Regarding the "evolved from," this isn't so much my language as the creationist's. And as a layman's simplification, I think it's ok to say humans and great apes evolved from something like an ape. Still, you are technically right here.

The bigger disagreement I have is with your second point regarding the "advanced" language. While I've heard your argument many times (including from distinguished scientists), I don't agree with it--at least not entirely.

True, evolution "merely" helps living things adapt, but I don't think we can really say that there are no objective differences between various living things. You mention tigers and fish, but what about bacteria? Are humans no more advanced? Again, you raise a valid point about evolution, but I think it's fair for reasonable people to cry foul when evolutionists (also known simply as "biologists") make this claim. It may be valid, but it requires qualifications and extra explanation, and as such is not a strong argument, in my opinion.

It's a valid point that humans shouldn't be seen as standing at the top of a pyramid of life. But it's also apparent that the human brain (for example) is far more complex than the brains of other animals. I think evolutionists sound like they are grasping at straws when they try to diminish this fact.

Another way to state the argument about adaptation is that animals (including humans) are adapted to their mode of life. Fine, but you would have to say the human mode of life is far more complex than that of other animals. What other creature can live, work, socialize, play, etc in so many very diverse and complex ways? Or what other creature can adapt itself (by will!) to so many diverse environments? There is an obvious complexity here, call it "adaptation" or "advanced" or whatever you will. It's fair to say humans are the most notable of living creatures (on Earth, that way know of, at least).

Having said all that, I like to point out to creationists that complex living things (e.g. vertebrates) are really just collections of individual cells. In that sense, we truly are very similar to bacteria! There are simply more cells and many more specialized cells in the human body. This arrangement is hard to explain from an "ex nihilo" worldview.

Further, you can quite easily say that most of the "specialized" cells in humans can also be found in other animals (not only the apes). So we may have MORE brain cells, but apes have them all the same--just not in the same quantity. Again, this is a curious state of affairs for the creationist as they must explain why so much of life seems to be shared/related. As I've mentioned before, designers don't design in this way (at least not when they are seeking to be efficient and practical).

 
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