Showing posts with label evolutionary theory. Show all posts
Showing posts with label evolutionary theory. Show all posts

Saturday, October 31, 2009

Book review: Why Evolution is True

This is one of those great science books that the people who need to read it the most will never touch.  It is, as the dust jacket blurbs promise, a succinct and thorough evaluation of evolutionary theory written in terms a nonscientist can easily understand.  The author, Jerry A. Coyne, summarizes the Charles Darwin's 19th century work in early development of evolutionary theory, lays out the theory's key ideas -- evolution, gradualism, speciation, common ancestry, natural selection, and the recognition that processes other than natural selection can cause evolutionary change -- and then explicates in detail each of those concepts.  The book explains evolution clearly, concisely, and stacks up so much supporting evidence it's guaranteed to make a creationist's head explode.

Coyne begins with the basics:  what is a theory in science?  One of the mantras of the creationists is that evolutionary theory is "just a theory."  Saying that labels the speaker immediately as someone who lacks a basic understanding of science and how science works.  Of course evolutionary theory is just a theory, just as gravitational theory is just a theory; so what?  In science a theory is a possible explanation or collection of related explanations used in an attempt to understand a fact or phenomenon.  Evolution is a fact; the evidence is all around that organisms evolved and continue to evolve; evolutionary theory explains evolution. 

But more than explain a phenomenon, a scientific theory has other properties:  it has to be testable, or potentially falsifible.  In the case of evolutionary theory, when we're surrounded by ongoing, continuous evidence of it happening (pandemic influenza A(H1N1) 2009 being the most recent example to spring to mind), what would falsify it?  Finding fossils known to be from organisms that lived in one distinct geologic era embedded in rock side by side with organisms from another could do it.  An obvious example would be fossilized mammals, which first appeared about 250 million years ago, embedded in geologic strata from a much earlier time period, like the Silurian (over 400 million years ago).  This is one reason some creationists will go to extraordinary lengths to try to prove that humans co-existed with brontosaurs (they apparently think The Flintstones was reality tv). 

Another way to disprove a theory is to use it to make predictions -- and if the predictions don't come true, then the theory may be fatally flawed.  Unfortunately for the doubters, evolutionary theory to date has proved remarkably accurate in its predictions.  A criticism of evolutionary theory used to be that various transitional forms did not exist, e.g., if, as scientists claimed, creatures like whales evolved from land mammals then there should be fossilized whales with legs.  I know a few folks who were quite proud of making that argument 20 or 30 years ago.  Bad news for them:  paleontologists have found a veritable plethora of legged whales, the transitional forms between land mammals and marine.  Evolutionary theory predicted not only that such forms would be found, but in what geologic era.   

In short, Coyne's book explains evolutionary theory and provides numerous examples to support it. The book is extremely readable and loaded with interesting tidbits from the history of science and the natural sciences.  Unfortunately, as Coyne himself admits, even though one would think so much compelling evidence would help to change a few minds, it probably won't. 

Thursday, August 27, 2009

Book review: Your Inner Fish

Neil Shubin's Your Inner Fish is one of the best science books I've read in a long time. Shubin manages to explain paleontology, human anatomy, evolutionary theory, and geology in terms the average semi-literate reader can understand -- and does it all seamlessly in a fairly small number of pages. Your Inner Fish had been on my "must read" list since it was published last year, and now I'm wishing I had gotten around to it sooner.

Shubin looks at various parts of the human body -- the hand, the bones of the inner ear, and others -- and explains how the fossil record shows those body parts evolving over time. It's fascinating. Who would have thought that the auditory ossicles started off as part of the jaw and moved over millennia?

While he's doing that, he's also throwing in personal anecdotes about the joys of field work (he's been doing his in the Arctic so the hazards he gets to deal with include polar bears), explaining geology, casually explaining genetics and mutations, and describing both how fossils form and how paleontologists decide where to go looking for them. It's a great book for anyone who has any interest at all in the how and why of science.

This book was one of those rare ones, too, in nonfiction where you pick it up and get sucked right in. It's actually fast, fairly easy reading. I zipped through it in a couple evenings. I spent actual money on this book instead of looking for it at the library, and it was money well spent.