Sunday, July 25, 2010

Some Suggested Science Reading

Caption: A bulb tipped anemone at the Seattle Aquarium. (Click to enlarge)

Image credit: Cujo359

If you're interested in some science reading today, and hadn't stopped by Pharyngula recently, I'd suggest checking out an article that PZ Myers wrote yesterday. It starts out with this attempt at explaining what evolution is, which he quickly noted isn't an accurate one:

Evolution proceeds by mutation and selection. A novel mutation occurs in a gene that gives the individual inheriting it an advantage, and that person passes it on to their children who also gets the advantage and do better than their peers, and leave more offspring. Given time, the advantageous mutation spreads through the population so the entire species has it.

One example is the human brain. An ape man millions of years ago acquired a mutation that made his or her brain slightly larger, and since those individuals were slightly smarter than other ape men, it spread through the population. Then later, other mutations occured and were selected for and so human brains gradually got larger and larger.

It's More Than Genes, It's Networks And Systems

Not being a biologist, I wasn't too sure what to think. This explanation struck me as way oversimplified, which it turns out it is:

Just to make you even more queasy, the misunderstanding here is one that creationists have, too. If you've ever encountered the cryptic phrase "RM+NS" ("random mutation + natural selection") used as a pejorative on a creationist site, you've found someone with this affliction. They've got it completely wrong.

Here's the problem, and also a brief introduction to Evolutionary Biology 201.

First, it's not exactly wrong — it's more like taking one good explanation of certain kinds of evolution and making it a sweeping claim that that is how all evolution works. By reducing it to this one scheme, though, it makes evolution far too plodding and linear, and reduces it all to a sort of personal narrative.

It's More Than Genes, It's Networks And Systems

After reading The Waters Edge by Carl Zimmer, and Your Inner Fish by Neil Shubin, I have a new appreciation for just how complicated the process of going from a genetic code to an organism is, and all of the things that go into that affect the evolution of organisms. For instance, there are both genes that actually determine how various tissues develop, and others that decide whether or not those traits are expressed, and how large they become.

What's more, a species is really a population of organisms. There's no one perfect gray wolf or perfect fern. There are populations of gray wolves and ferns that are each unique.

So, yes, it's much more complicated. In fact, it's a lot more complicated than I can hope to explain correctly. Read PZ's article for an idea of what evolution really is.


Expat said...

One of the very best writers on the subject and nature of evolution (outside C. Darwin himself) sadly was the late Stephen Jay Gould. His "Wonderful Life, The Burgess Shale and the Nature of History" (ISBN 0-393-02705-8) is written with enthusiasm, love, and respect for the idea. Some items he mentions have been changed by further studies but on the whole the essay stands the test of time. For a wonderful glimpse of geologic history, this book should not be missed.

Cujo359 said...

Believe it or not, I have that book. It's on the reading list. Gould's Full House is another interesting read, partly because it tries to explain how biologists view species as statistical phenomena.