Science & Nature Archive

Friday, March 28, 2008

A (Somewhat) Brief Introduction to Evolution

Evolutionary TreeThe other night, we went out to eat with some friends. I forget why, but for whatever reason my daughter was going through, with our help, trying to think up a mammal for every letter of the alphabet (aardvark, bear, cat...) Well, for P she picked platypus, so when the game was all over, it got us to talking about them. And I foget exactly how the next part came up, but the guy I was talking to brought up that he couldn't see how they were related to other mammals, and that he really doubted the whole theory of evolution. I tell ya what - get a couple beers in me and then tell me you don't accept evolution, and just see what type of conversation gets going. Boy, was it fun. Unfortunately, I don't think I did much convincing. It had nothing to do with the beer, but a whole lot to do with the fact that discussions like that are basically my word vs. your word. Considering that I'm not a biologist or in any related field, and it makes my word worth that much less. So, I decided to write up an e-mail to send him, along with links to lots of sources backing it up. Once I got through with typing it, I figured that it made for a decent general introduction to evolution. Maybe at some point I'll clean it up and make a good essay out of it, but even in its rough e-mail form, I figure it makes for a decent blog entry. So, if you want to read it, go head below the fold.

Continue reading "A (Somewhat) Brief Introduction to Evolution" »

Friday, March 7, 2008

Book Review - At the Water's Edge

The full title of this book is At the Water's Edge : Fish with Fingers, Whales with Legs, and How Life Came Ashore but Then Went Back to Sea. It was written by Carl Zimmer, and as the long title suggests, is all about those two dramatic transitions of life evolving into such distinct environments. This book was great - one of the best non-fiction books I've read in a while. It was just the right blend of story telling, concepts, and evidence, and made for a very compelling read. In fact, I think I finished it in less than a week.

When I reviewed another book by Zimmer, the Smithsonian Intimate Guide to Human Origins, I commented that it wasn't very in depth. At only 176 pages, much of them filled with photos and illustrations, it was a little light on commentary. At the Water's Edge is very different in this regard. It's 304 pages, filled with small print, with only enough diagrams as are needed to illustrate a few key points. It's not a tome, by any means, but it certainly provides Zimmer with enough space to do this subject justice.

The book is divided into basically two halves - the first dealing with the transition from lobe finned fish to early tetrapods, and the second half dealing with the transition from mesonychids to dolphins and whales. As would be expected, both halves deal with the specifics of each of those cases - transitional forms that have been discovered, environmental pressures that would drive the transition, etc. However, mixed throughout the entire book are also sections on general theory. There's a nice section on development in the beginning, covering such topics as Hox genes and non-genetic factors; he describes exaptation; there's another section on cladistics; as well as sections on many other concepts related to evolution.

I learned quite a bit by reading this book. Even though I was already familiar with much of the general theory, Zimmer presented it in ways that made me think of things differently. He also introduced a few concepts, such as the evolutionary "quit point," that I hadn't thought of much before. Still, where I learned the most was in those specifics of the transitional forms between fish and tetrapods, and land mammals and whales.

I'll give one example of something very interesting I learned from this book. (In fact, this was the very first passage of the book that I read, when I first got it and was just thumbing through to see what it was like.) At some point, our ancestors must have developed lungs to breathe air, obviously. When we look at the world around us, most fish today cannot breathe atmospheric air - they rely on their gills to get oxygen from water, but also have organs similar to lungs called swim bladders, which they use to regulate their buoyancy. From that observation, you may be tempted to think that lungs are a modified swim bladder, which perhaps evolved to allow fish to survive in swamps or other oxygen poor environments. After all, what need would an ocean going fish have of lungs? I know that's what I had thought, but as it turns out, it's almost certainly wrong.

Continue reading "Book Review - At the Water's Edge" »

Friday, February 22, 2008

Book Review - Smithsonian Intimate Guide to Human Origins

I already posted a brief review of this book in my review of the Lucy's Legacy Exhibit at the Houston Museum of Natural Science. I don't really have much to add, but I thought I ought to at least give that review some closure, since I'd only read 2/3 of the book when I wrote it. I also figured this would give me a good chance to get the review into my Books section.

The book is the Smithsonian Intimate Guide to Human Origins, by Carl Zimmer. I liked it. It's not very in depth - it only took me about one weekend to read the whole thing - so if you follow science news, you probably won't learn a whole lot from it. That's not to say you won't learn anything - I certainly did learn a few things from this book, but most of the information was a review of what I alread knew.

But, it does have lots of pretty pictures that make it worth the price. And I mean that in the best possible way - paragraphs are all well and good, and it would be impossible to teach evolution with nothing but glossy pictures, but it can be nice to have a page full of pictures of fossil skulls, to see with your own eyes the similarities and differences. Sometimes pictures do show things more clearly than words ever could. Plus, if you don't follow science news as much as I do, or happen to know a person who doesn't know much about human evolution, it makes for a very good overview. If someone doesn't want to read the whole thing, but they're willing to listen to you explain something to them, you can still use the book, and open it up to some of those pretty pictures to help illustrate your point.

Tuesday, February 12, 2008

Book Review - Voyage of the Beagle

In honor of Darwin Day, I figured I'd post a review of The Voyage of the Beagle, which I just recently finished reading. The edition I read was actually the one from The Folio Society, given to me as a gift, and not the one pictured at right from Amazon. The book is also available as a free download from Project Gutenberg as a text only version, or as html with pictures, or from The Complete Works of Charles Darwin Online.

There are many reasons to like this book. One can't ignore the historical importance, since this expedition gave Darwin much of the insight that would lead to developing the theory of evolution, but this book would still be interesting even if Darwin had gone on to do nothing after sailing on the Beagle. The book is basically the journal of a young man on a round the world voyage, visiting much of South America, Tahiti, Australia, and a few other places, describing all the different cultures, geographies, and animals that he encountered.

For this review, I'll quote heavily from The Voyage of the Beagle, letting Darwin speak for himself, to give the reader a better idea of the language of the book. But first, let's get the somewhat confusing background out of the way. Darwin went along on the second survey expedition of the HMS Beagle. The first expedition, begun in 1826, consisted of two ships, the larger HMS Adventure, captained by Phillip Parker King, and the smaller HMS Beagle, captained by Pringle Stokes. Stokes committed suicide near the end of the first expedition, and 23 year old Flag Lieutenant Robert FitzRoy was named as temporary captain of the Beagle. On the second expedition, begun in 1831, only the Beagle returned, and as FitzRoy had proven himself well enough as temporary captain on the first expedition, he was given command of the ship for this second expedition. Worried about becoming depressed and suffering the same fate as Stokes, FitzRoy invited Darwin along for the journey so that he could have someone to talk to. As survey expeditions, the main purpose was acquiring data to produce nautical charts. Darwin had a slightly different agenda, as a naturalist, collecting many samples of the flora & fauna and taking many notes along the way. After the expeditions' completion, a four volume account was published, titled, Narrative of the Surveying Voyages of His Majesty's Ships Adventure and Beagle. The third volume of this narrative was written by Darwin, and titled, Journal and Remarks, 1832--1835. Darwin's volume proved to be so popular that the publisher, Henry Colburn of London, decided to publish it as a stand alone book, renamed, Journal of Researches into the Geology and Natural History of the various countries visited by H.M.S. Beagle. The book was published several more times under several different titles, but is most commonly referred to today as The Voyage of the Beagle.

Continue reading "Book Review - Voyage of the Beagle" »

Thursday, October 18, 2007

Book Review - Origin of Species

Well, I just announced that I was starting a new Books section, so I figure I ought to post a book review. But, I'm going to cheat a little on this first one - I'm going to combine two previous posts, with a little bit of editing, and adding only a paragraph's worth of new content.

The book is the classic, Darwin's The Origin of Species. Long before I picked up the book, I already had a pretty good understanding of evolution - better than most laymen, I'd wager. So I didn't start reading Origin of Species to try to learn anything about the theory. Rather, it was more to do with my interest in history, particularly my interest in the history of science and technology. And it doesn't disappoint.

Continue reading "Book Review - Origin of Species" »


Selling Out