Science & Nature Archive

Monday, March 19, 2007


BodyWorlds Whole Body PlastinateThis past weekend, my family and I went down to Dallas to see BodyWorlds, the traveling museum exhibit that shows preserved human bodies in various poses and various states of dissection. After reading PZ Myers' review on Pharyngula, I was a little worried that it was going to be too artsy. But I have to say, it was great. After reading a few reviews from other locations, it seems like certain locations may not get the full exhibit, either because the venue isn't large enough for all the exhibits, or political pressure keeps the museum from displaying all of the specimens, but it seemed like Dallas had quite a bit.

If you haven't heard of this exhibit, yet, like I said above, it's made up of many specimens of preserved humans. The preservation process is called plastination, which, to quote the Dallas Museum of Nature and Science, "Plastination, invented by German anatomist Dr. Gunther von Hagens in 1977, is a process whereby all bodily fluids and soluble fats are replaced with reactive plastics that harden after curing with light, heat or gas. All tissue structures are retained." To make things even more interesting, the bodies have been dissected in various ways to show off different aspects of human anatomy (and a handful of other animals, as well). For example, there are some specimens that show all of the muscles, others that show the circulatory system, others that show the nerves, and yet others that show different combinations of systems, so that you can see how it all works together. Yes, a few of the specimens may have been overly artistic, but those were the exception, and not the rule. Aside from the "whole body plastinates" in poses, there were several specimens of whole bodies that were sliced into ~1/4" sections. These were another, very interesting, and very informative way to show how the body fits together. On top of that, there were many, many more specimens that were of individual organs, or smaller groups of organs (such as the digestive system), also disected in various ways. These included not just healthy, but also abnormal and diseased tissues, so you could see what they looked like. It also showed how much variation there is from person to person.

One of the other complaints from Myers' review that had me a little worried was this, "I like my biology wet. It's supposed to be vital and dynamic and messy and complicated, but it all ties together into a lovely integrated whole. A collection of plastinated cadavers is precisely the opposite of what I enjoy about the science: it's dead and static and distressingly dry." So here's my response to that. In our trips to Guatemala (2005 & 2006), I've been lucky enough to help out in a few of the operations and get a peek inside of a living body. My wife's a nurse, so she's gotten to see much more than I have, and she had to go through all of those anatomy classes to get her degree. And both of us thoroughly enjoyed BodyWorlds. It gives you the type of overall view that you just can't get unless you actually perform your own dissection, and that's certainly not something that's going to be available to most people. The closest most of us will ever get to that is dissecting non-human animals, which although informative, just isn't the same as seeing the inside of your own species.

One more positive review is the fact that my 7 year old daughter was interested enough in the whole thing to spend an hour and a half looking at it, up until the time they closed the exhibit and kicked us out. She probably would have spent a little more time there if we'd had it.

I guess I ought to make note of the general mood. It was, after all, an exhibit full of dead people. The atmosphere was respectful, almost like a cemetary, with everybody talking in hushed tones. For the most part, I wasn't too bothered by it, since these were mostly adults who had lived (hopefully) full lives, and who had willed their bodies to this exhibit. There's still the sense that these were once living, feeling people who were now gone, but the presentation, and the knowledge that this was how these people wanted to be remembered, kept it from being sad. That is, all the exhibits except for the babies. I must admit, those were very moving. If you think that would bother you too much, the way the exhibit was laid out in Dallas, you could bypass that section if you wanted to. But even though it was sad, I think it was still worth seeing.

So, if you're reading this and planning on going to see BodyWorlds, my advice is to buy your tickets a few days in advance. The exhibit is so popular that the Dallas museum has expanded their hours to 9 am till 9 pm. And even at that, they're selling out. We waited until the night before to buy our tickets, and they were all sold out until the 7:15 pm entry time - 7:30 was the last slot they sold tickets for (and because they were running late, we didn't get in until 7:30 - so we ended up having to rush a bit at the end just to see everything). Buy your tickets well ahead of time so you can go in the morning and look at your own pace, and then have plenty of time to go look at the rest of the Museum of Nature and Science.

Friday, March 9, 2007

More on Origin of Species

This is a follow-up to a previous entry. However, both of thses entries have been supplanted by a newer post, which combines the two, with a little editing, and a paragraph's worth of new content.

Cover of Origin of SpeciesWell, I finally finished reading Origin of Species (actually, I finished it a couple weeks ago, and I'm just now getting a chance to write about it). My impressions that I wrote about in a previous entry haven't really changed, but there were two other things that struck me that I wanted to write about.

First, and maybe this is just my fault for my own ignorance, but it's changed my perception of Darwin (kind of like as an aviation buff, I always get upset when people think of the Wright brothers as just tinkerers, and don't give them their proper due as engineers). The story you're always presented with about Darwin is this naturalist who went on a voyage on the Beagle to observe plants and animals, had an epiphany at the Galapagos islands, and came up with this theory of evolution. While this is true to a certain extent, and Darwin was a very keen observer, Origin of Species had more than just his observations from the Beagle and some interesting ideas to explain it. Let me give a couple examples. In one of the chapters on geographical distribution, Darwin discusses how certain plants might spread from one pond to the other. In addition to trying to think up plausible means, he then goes on to test how plausible they might be. Consider this passage, discussing the possibility of seeds sticking to water fowl and being transported from pond to pond in that way:

I do not believe that botanists are aware how charged the mud of ponds is with seeds: I have tried several little experiments, but will here give only the most striking case: I took in February three table-spoonfuls of mud from three different points, beneath water, on the edge of a little pond; this mud when dry weighed only 6 3/4 ounces; I kept it covered up in my study for six months, pulling up and counting each plant as it grew; the plants were of many kinds, and were altogether 537 in number; and yet the viscid mud was all contained in a breakfast cup!

Later in the same chapter, Darwin discusses inhabitants of oceanic islands, and the problem of how certain animals could have come to live on them. I'll just let Darwin speak for himself on this one:

Almost all oceanic islands, even the most isolated and smallest, are inhabited by land-shells, generally by endemic species, but sometimes by species found elsewhere. Dr. Aug. A. Gould has given several interesting cases in regard to the land-shells of the islands of the Pacific. Now it is notorious that land-shells are very easily killed by salt; their eggs, at least such as I have tried, sink in sea-water and are killed by it. Yet there must be, on my view, some unknown, but highly efficient means for their transportal. Would the just-hatched young occasionally crawl on and adhere to the feet of birds roosting on the ground, and thus get transported? It occurred to me that land-shells, when hybernating and having a membranous diaphragm over the mouth of the shell, might be floated in chinks of drifted timber across moderately wide arms of the sea. And I found that several species did in this state withstand uninjured an immersion in sea-water during seven days: one of these shells was the Helix pomatia, and after it had again hybernated I put it in sea-water for twenty days, and it perfectly recovered. As this species has a thick calcareous operculum, I removed it, and when it had formed a new membranous one, I immersed it for fourteen days in sea-water, and it recovered and crawled away: but more experiments are wanted on this head.

It's this practical approach from Darwin that impressed me. He didn't just sit around trying to come up with just-so stories - when he came to a question, he'd go and get his hands dirty doing real experiments.

The other thing I wanted to discuss from Origin of Species is how it made me appreciate how much we know now. Let me explain this a bit - right now, there's a lot we don't know about a lot of things in the universe, and it kind of fills you with a longing to know the answers, even though you know you won't survive long enough to learn them. Like life on other planets - I would love to travel to other solar systems and see how complex life has developed on them, what strategies and structures have evolved in an environment completely isolated from our own, but I know that that's something I'll never know. Now, consider Darwin's condition in relation to his theory, having the limited evidence that he did. In the final chapter of Origin, Darwin wrote, "Numerous existing doubtful forms could be named which are probably varieties; but who will pretend that in future ages so many fossil links will be discovered, that naturalists will be able to decide, on the common view, whether or not these doubtful forms are varieties?" We are those "future ages!" Granted, our knowledge of the fossil record is still far from perfect, but we've discovered so many things since Darwin's time. For example, we now have a pretty good idea how whales evolved, how the first tetrapods went from water to land, how birds evolved from dinosaurs, and so many other things that Darwin could only dream of. So, while I'll still long to know the things I can't, I can at least be grateful for the things we know now, that were the longings of people in the past.

Monday, February 12, 2007

Review of Darwin's Origin of Species

There is a follow-up to this review, written after I finished reading the book. However, both of thses entries have been supplanted by a newer post, which combines the two, with a little editing, and a paragraph's worth of new content.

Cover of Origin of SpeciesSince today is Darwin Day, I figured I ought to post something. As it turns out, I'm currently reading The Origin of Species. I'm not quite done with it, yet - only about 2/3 of the way through - but I wasn't intending to write an in-depth review, anyway; I was only going to cover my general impressions of the book. So, with today being the day it is, I figured this would be a good time to do it, as I doubt my opinion will be changed much with the last third of the book.

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 for this case my interest in the history of science and technology, that was the reason I wanted to read this. And it doesn't disappoint.

Okay, let's get the background out of the way, first. Origin of Species was published in 1859, with the full title, On the Origin of Species By Means of Natural Selection, or, the Preservation of Favoured Races in the Struggle for Life. It's not that Darwin was the first to propose some type of evolution and common descent, but Origin of Species really was the book that presented the evidence in such a way, and proposed a plausible mechanism, that the theory really came to be accepted.

Part of what I find just so fascinating is how Darwin came up with all this without any knowledge of genetics. Even though Gregor Mendel was performing his pea plant experiments around the same time that Darwin wrote Origin of Species, it appears that Darwin wasn't really aware of Mendel's work. In fact, it wasn't until the early 1900's that the scientific community recognized the importance of Mendel's experiments. And it wasn't until the 1940's and 50's that people finally understood what DNA was and how it controlled heredity. Obviously, people in the 1800's knew that offspring bore some resemblance to their parents, but nobody knew how exactly this happened, or what it was that caused offspring to have variations. So Darwin was kind of left groping around in the dark, and all throughout the book, he's reduced to explaining concepts while admitting that he doesn't truly understand the mechanisms responible. From a modern viewpoint, understanding genetics, it almost makes you wish you could travel back and explain it to Darwin. It would have made things so much easier for him.

So knowing that Darwin was ignorant of genetics, and knowing that our knowledge of the geologic record was even less complete then than it is now, it's interesting to see the insights Darwin had that lead him to formulate the theory. For me, when I think of evolution, I think of fossils. Yeah, I know there are multiple other lines of evidence, but growing up, that was the main line of evidence that convinced me that evolution actually happened. But Darwin only briefly discusses fossils in two chapters of the book. The rest of Origin of Species is about what he observed in the world around him - how there seem to be clusters of similar species, the difficulties of distinguishing between true species and merely varieties of the same species, the geographical distribution of species, etc.

It's also interesting how Darwin determined that variation and natural selection were the mechanisms responsible for evolution. Consider one of Darwin's contemporaries, Jean-Baptiste Lamarck. Lamarck came up with the idea of "Use and Disuse," that animals could affect their own bodies through their actions, and that they could then pass on these acquired traits to their offspring. The classic example of this is a giraffe stretching its neck to reach higher leaves, and it's offspring thus having a longer neck because of it. Thanks to genetics, we now know this is a false view. To be fair, Darwin didn't rule this out entirely in Origin of Species, but he concluded that it must have been secondary to variation and natural selection. And one of the best examples he used to demonstrate this was ants - all the variation evident in workers, even though it's the queen that lays eggs.

I also find it fascinating to read Darwin comparing evolution to special creation, to think that creationism was the dominant scientific theory of the time. What I find especially fascinating, is to think how people integrated this into the knowledge of an ancient earth. Darwin fequently cited Charles Lyell in Orign of Species (Charles Lyell was one of the early popularisers of uniformitarianism, and helped promote the idea of the Earth being truly ancient), and in his chapters on the geological record, Darwin discussed some of the different geological periods. And concerning fossils appearing in the geological record, Darwin tells of how people proposed that those species were created during those periods. Just imagine that - seeing all the evidence for an ancient earth, and thinking that different species had been specially created throughout the history of the earth. I suppose without a better explanation, that's all the people could come up with then, but it certainly does seem an odd idea now.

I've read other places that evolution, through Origin of Species, was one of the last major scientific theories that was first presented to the world in a book intended for a lay audience. It wasn't presented in a peer reviewed journal; it wasn't full of technical jargon or equations; it was a book published by a regular publisher and sold through normal venues. It was easy to understand, and became a best seller. Now we need science writers to translate for us lay people, so we're always a few steps removed from the real science. It's hard to imagine any new major theories being presented the same way evolution was in Origin of Species.

I'd recommend this book to anyone with a good understanding of evolution who's interested in the history of the theory, but not necessarily to those people who don't undertand evolution, yet. For one thing, Darwin gets a few things wrong. For another, being written in a style 150 years old, it's not the easiest thing for a modern reader to understand. And finally, genetics is such a huge component of evolution, that a good introduction to evolution should include genetics in its explanation.

Anyway, despite any mistakes he may have made, Darwin certainly made a huge contribution to our understanding of the world. Happy Darwin Day, everybody.

Tuesday, February 6, 2007

Upcoming Darwing Day Event in Wichita Falls

Darwin Day GraphicWhile reading the latest entry on The Loom, I found out that there's actually a holiday called Darwin Day. Following the link that Zimmer provided, I found that there's even an event going on right here in my own hometown of Wichita Falls. Whoda thunk it? I doubt I'll go, but it's nice to see things like that here in this part of Texas.

(Yeah, I stole that picture from Zimmer, but I figured that a caricature from the 1800's was probably in the public domain by now.)

Thursday, August 24, 2006

Knowledge for Knowledge's Sake

This is something I wrote the other day in the comments of a TerrapinTables thread. It's short, but I like it enough that I wanted to post it here on my own blog. It was in response to the following question posed in relation to studying dark matter (prompted by this article), "But tell me this: first, I mean, seriously, aside from knowledge for knowldege's sake, why do we need to know what comprises a galaxy cluster infinity-miles away?" Here is my reply:

First off - I think knowledge for knowledge's sake is a good enough reason to do research. In the same way that some people may find beauty in a painting, others can find beauty in a deeper understanding of the mysteries of our universe. If you're going to question why we need to know about a substance that composes 1/4 of the universe, I could just as easily ask why we have an entire profession dedicated to smearing paint on canvas, or another profession dedicated to plucking guitar strings and beating on drums. (Don't take me the wrong way - I'm not saying the arts aren't worthwhile; I'm saying that I think pure knowledge with no practical applications is just as important.)

But aside from that, who knows where knowledge will lead? Like in the 19th century, when physicists were trying to measure the ether that light travels in, could they have known that it would eventually lead to such practical applications as lasers, CDs and DVDs? Or the geologists of that era, did they really start off thinking that their theories would lead to the abandonment of a literal interpretation of the bible (at least in most of the developed world, not counting the U.S.)?

So there you go - one example of knowledge that led to practical technical applications, and another that had huge societal & cultural implications. I'm sure I could go on listing more, but you get the point.


Selling Out