On a recent trip to the Houston Museum of Natural Science, I bought a ticket to see the the exhibit, Archaeopteryx: Icon of Evolution (related link). The exhibit was a fascinating collection of fossils from the Solnhofen region of Germany, with an archaeopteryx known as the Thermopolis specimen as the centerpiece. The archaeopteryx fossil was very interesting, but there were two things about it, in particular, that I was struck by. First was the size. For some reason, in my mind's eye, archaeopteryx had always been a big bird, something along the lines of an eagle. The archaeopteryx fossil at the museum was about the size of a crow (more on this below). Second was the level of detail in the feather imprints, which photos just don't do justice to. It's not that the feathers were imprinted perfectly in their entirety, but in the regions where the preservation was best, it was very obvious that you were looking at an actual feather.

The Thermopolis Archaeopteryx, With a Hand for Comparison to Show Size

So, after I left the exhibit, I went to the museum gift shop to find a souvenir. About the only thing they had that was appropriate for an adult was the book, Archaeopteryx: The Icon of Evolution, by Peter Wellnhofer*.

Before I get started with my own review, let me note that the publisher has a great section for the book. Perhaps best for someone considering buying the book is the section of sample pages. The pages shown are not anomalous - nearly every page had many illustrations, which was great. Also note the small text size and amount of text per page. Even though the book was only 208 pages, it was an information packed 208 pages.

The book was divided into several sections. The first was a short description of the locale where the fossils were found, the Solnhofen region of Bavaria, in Germany. It was the sort of description you'd expect from a chamber of commerce.

Next came a brief description of the geology of the Solnhofen region, and what this tells us about the ancient environment of the area. All of the archaeopteryx specimens found so far have come from Solnhofen Jurassic limestone deposits. It turns out that these deposits were from lagoons in shallow seas. The water was apparently fairly calm, and formed stratified regions with very low oxygen levels at the sea floor - no multicellular life could survive in those anoxic conditions. The mainland was not very close, but it's possible there were islands nearby. So, the limestone deposits were necessarily not the native habitats of any of the terrestrial animals found there. It's possible that the archaeopteryx were blown out to sea during storms, and didn't have the strength to fly back to land (the fact that all archaeopteryx found thus far are juveniles supports this idea).

Death March of a Horseshoe Crab, Which Died after Wandering into an Anoxic Lagoon

After that came a discussion of the history of fossil discovery in the Solnhofen. Obviously, being a marine environment, most of the fossils from the region are from sea creatures, with the fossils of terrestrial animals being very rare. Because of the way the fossils were formed, the preservation is excellent, and Solnhofen fossils have been prized for centuries. They were regular inclusions in the curiosity cabinets of medieval Europe, which emerged in the 16th century (some of the best collections served as the start of modern museums).

Next came the heart of the book - 83 pages discussing the known archaeopteryx specimens in detail. If you think 83 pages of discussion sounds like a lot - it was, and it was a bit dry. I think of myself as a fairly knowledgeable layperson when it comes to evolution and biology, but much this section was a bit advanced for me. The fossils were described in technical terms (radius, ulna, meta carpal, flexor tubercle, pneumatic foramina), which would have made a firm grounding in anatomy useful in understanding this chapter.

This section started with a discussion of how the urvogels (a common name for archaeopteryx from German, meaning proto bird) likely became fossils - they floated in the sea for a few days before sinking to the sea floor, where they were covered with a microbial film before being covered by sediment. One fact I found interesting is that the feathers formed an imprint in the sediment before decomposing, and then this imprint was transferred to the adjacent layer of sediment after the feather decomposed. So, when a slab containing an archaeopteryx is split, both new slabs show only one side of the feathers.

After discussing fossilization, this section moved on to the controversy in the nomenclature and taxonomy of archaeopteryx. The rules of taxonomy state if a species is named twice, the first description has precedence, even if it was obscure and few people heard of it, or if the type specimen wasn't as complete as the later one. (This, for example, is why brontosaurus is now referred to as apatosaurus, since apatosaurus was the first name used, even if it wasn't as widely known). An early archaeopteryx specimen, not being recognized as a bird, was named Pterodactylus crassipes, so crassipes should be the species name. But before that specimen was recognized as a bird, a fossil feather was discovered and used as the original type specimen for Archaeopteryx lithographica. Once subsequent archaeopteryx were discovered, they were named after the feather, even though it's not certain if the feather is actually from the same animal. Another ealy genus name was Griphosaurus. In the end, most people referred to the animals as archaeopteryx, so a special petition was made to the International Commission on Zoological Nomenclature in 1977 to make the London specimen the type specimen, and to make Archaeopteryx lithographica the official genus and species names.

There is, however, some controversy as to whether the archaeopteryx specimens found so far are actually all from the same species. Most notable is the size difference between the specimens, but there are also differences among the details of the anatomy. The size and some of these differences could be explained by the urvogels being different ages at their times of death, along with individual variability, or even sex differences. But, it's possible that the fossils represent more than one species.

Size Comparison of Archaeopteryx Specimens

Next came the discussion of each fossil. For each fossil, Wellnhofer gave a brief overview of how the fossil was discovered and brought into public light, followed by a detailed physical description, which as I already mentioned, was rather technical when it came to anatomy. Besides the feather (which may or may not be from an archaeopteryx), there have been 10 archaeopteryx specimens discovered so far, of differing levels of completeness and preservation. Most are now housed in museums, and are known by the city in which they're permanently located. In order of discovery (though not necessarily public knowledge), the specimens are the feather, London, Berlin, Maxberg, Haarlem, Eichstatt, Solnhofen, Munich, Burgermeister-Muller, the 9th, and Thermopolis specimens.

The first, and one of the most complete, was what is now known as the London specimen. It was discovered in 1861, just two years after Darwin published On the Origin of Species, and made quite a stir being such an obvious transitional form. Also notable is the Maxberg Specimen, which has gone missing since its owner's death. Luckily, casts were made of the fossil before it was lost, but casts are not as useful as the real thing.

Once all the fossils had been described, the next section was a sort of synthesis, describing as much as we can know about archaeopteryx from the fossils we've found. Wellnhofer started with the subject with the most certainty, the skeleton, and moved on from there through less certainty and more conjecture - plumage, physiology, then lifestyle.

The remaining four chapters were all related - discussing early bird evolution, and the role of archaeopteryx in understanding that story. Archaeopteryx is, after all, the oldest bird yet known (though not the first bird, as is too often mistakenly said). Wellnhofer discussed some of the leading hypotheses on the ancestor of birds, including the thecodont hypothesis and the crocodile hypothesis, along with a few more 'imaginative' theories. But the leading hypothesis, which is pretty much certain, is that birds are a lineage of dinosaurs, closely related to the maniraptoran theropods. They're so similar, actually, that there's some discussion as to whether some animals traditionally classified as non-avian dinosaurs are in fact birds that have secondarily lost the ability to fly (in the same manner as ostriches, but back when birds still had teeth and clawed hands).

One of the things that struck me is just how much more dinosaur-like than bird-like archaeopteryx was (yeah, yeah, I know - birds are dinosaurs, but I think my meaning is clear enough). In fact, the Solnhofen Specimen was originally mistaken for a Compsognathus theropod by an amateur collector. I've included two pictures from the book below to dramatically illustrate this (I apologize for the quality of the scans, but like I said in another review, I wasn't about to ruin the binding on my book just to make it lay flat in the scanner).

Comparison of Bambiraptor, Archaeopteryx, and a Modern Chicken - not to scale

Comparison of Archaeopteryx to a Modern Eagle - not to scale

Take a close look at those skeletons. If you had to pick which other animal archaeopteryx was most closely related to, it seems pretty obvious that it would be the bambiraptor. Archaeopteryx still had clawed hands, a hyperextensible 'killer' claw on its foot (though not shown in the above reconstruction), a long bondy tail, gastralia (the bones under the stomach), a more theropod pubis, and teeth in its mouth. Just as important is what archaeopteryx didn't have - a pygostyle, a keratinous beak, a large keeled sternum, fused hand bones, a fused tibiotarsus, or a fused tarsometatarsus. It also seems pretty likely that archaeopteryx lacked a bastard wing. And those are just some of the differences between archaeopteryx and modern birds.

I hadn't realized just how many ancient birds have been discovered that are younger than archaeopteryx. There are quite a few. In fact, the evolutionary story of birds following archaeopteryx is pretty well understood. The family tree below illustrates this. Note that archaeopteryx is most likely not actually the ancestor of today's birds. Like most animals, it was in a lineage that went extinct, which means it had a few traits it had evolved that set it apart from the surviving avian lineage. However, it's still a very valuable specimen for understanding what early birds were like.

Avian Family Tree

This discussion also helped to put into perspective the K-T mass extinction. You often hear that birds were the only lineage of dinosaurs to survive that event, which makes it seem like there must have been something extra special about birds. But look at that phylogenetic tree. Most birds died at the end of the Cretaceous along with their non-flying relatives. There may have been some advantage that the surviving lineage of birds possessed, or they may have just gotten lucky (similarly, most mammals also died out at the end of the Cretaceous).

Despite there not being any known birds older than archaeopteryx, in recent years, paleontologists have discovered quite a few feathered dinosaurs. The book discussed a few of those dinosaurs, and compared the structure of their feathers to those of archaeopteryx and birds. The dinosaur feathers are more primitive. Some are just a downy covering, but some more advanced feathers do resemble the flight feathers of birds, only lacking the asymmetry. While the downy feathers were likely used for insulation, the function of those flight-like feathers is still uncertain.

Wellnhofer also covered the ground up versus trees down debate on the origin of flight. Up until I heard of this debate a few years ago, I'd always assumed that avian flight must have evolved from the trees down. It didn't seem plausible that it would have developed any other way. But many people have made compelling arguments for how it could have evolved from the ground up, where the wings would initially have been used for balance, and then maybe flapped for extra thrust to increase running speed, before fully developing flight. It's interesting that the flapping motion of a bird wing is very similar to the motion possible in a maniraptoran arm (most likely used to capture prey).

Perhaps the best evidence for the ground up hypothesis is that archaeopteryx very strongly appears to be a fully terrestrial animal, with no special adaptations for an arboreal lifestyle. Since archaeopteryx wasn't the first bird, it's possible that archaeopteryx secondarily evolved a terrestrial lifestyle, but given its similarities to the theropods, this seems unlikely. One proposed evolutionary stage in the ground up scenario, wing-assisted incline running, is supported by observation of living birds. The idea has also been proposed that flight may have evolved from jumping and parachuting from cliffs or other elevated points, followed later by gliding, as a sort of reconciliation between the trees down and ground up hypotheses, but eliminating the trees.

The ground up hypothesis certainly seems to be the more likely at this point, but as Wellnhofer pointed out, all ideas on this are speculative for the time being, since we haven't found the fossils of earlier birds.

Archaeopteryx: The Icon of Evolution was a very interesting book. It's very informative and detailed, and I learned quite a bit from it. I wouldn't recommend it for everybody, though. The target audience is quite a bit higher than the general layperson. Although some sections would probably be interesting to many people, if you only have a passing interest in archaeopteryx, maybe Wikipedia is a better choice. But if you happen to have a really strong interest in avian evolution, and don't mind reading technical jargon, then this is the book for you.

Update 2011-08-02 - A new fossil, xiaotingia zhengi, has been found that sheds further light on the evolution of archaeopteryx like animals. A cladistics analysis using this fossil suggests that archaeopteryx might not be quite as closely related to birds as previously thought. You can read more about it in a new entry, Is Archaeopteryx Still a Bird?

Update 2010-09-28 - I reworded several sections to make them more clear, particularly the section on the origin of flight. I also added a bit of information to the section on the origin of feathers.

* Although I commonly buy books as souvenirs from museums, this one was a little more expensive that I was willing to pay, so I walked out of the museum without it. However, my wife and daughter, seeing how interested I was in it, bought it without me noticing, and gave it to me later as a Father's Day present. Actually, it was my daughter's girl scout troop leader who bought the book, who then gave it to my wife when I wasn't looking. The full story is that we were at the museum as part of a girl scout trip. My wife was an official full time chaperon for the trip, and although I helped with chaperoning duties for most of the time, since I wasn't officially one, I was free to go off and do my own thing if I wanted to. Since the tickets to the archaeopteryx exhibit cost extra, it was out of the budget for the girls, so I went through the exhibit by myself. I would have liked to have taken the girls, but to be honest, I think they were all fossiled out after the museum's main exhibits. At the least, they definitely wouldn't have taken as much time as I had.

Posted by Jeff on Friday, Sep 10 | Permalink | Comments (27) | TrackBacks (0)

The Year of Living Biblically: One Man's Humble Quest to Follow the Bible as Literally as Possible was written by A.J. Jacobs. As the name suggests, for a year, he attempted to live his life by following the Bible literally, from observing the Sabbath, to not wearing mixed fiber clothes, to stoning an adulterer (he threw a pebble), to all the other myriad rules. The first 3/4 of the year were dedicated to just the Old Testament, since Jacobs is (nominally) Jewish (he described himself as "Jewish in the same way the Olive Garden is an Italian restaurant. Which is to say: not very."), and the latter part of the year to adding in the New Testament rules.

In the following paragraphs, I'll discuss quite a few things from the book where I disagree with Jacobs, but don't let that bias you from reading the book. This is a blog, so it's my duty to disagree and be vocal about it, so I've focused on the areas of the book that I disagree with the most. But overall, the book is very good, and very thoughtful.

Jacobs did seek advisors in his quest, people to help him understand the meaning of different passages. He explained in several parts what some of the more traditional, non-literal interpretations were of different passages (which, of course, he didn't follow, since his quest was to follow a literal interpretation). He also explained how people got around some the contradictions in the Bible, and a bit of the rationale many Christians use for no longer following Old Testament rules. It wasn't simply one long running joke about how silly Biblical literalism is - it was in many ways a sincere attempt to understand Judaism and Christianity.

I do question Jacobs' motivation somewhat. Consider this passage from when he went to Jerusalem.

As I wander over to a café near the hotel for a bagel, I realize something: Walking around Jerusalem in my bilbical persona is at once freeing and vaguely disappointing. In New York - even though it's home to the Naked Cowboy and gene Shalit - I'm still unusual enough to stand out. But in Israel I'm just one of the messianic crowd. A guy with strange outfits and eccentric facial hair? Big deal. Seen three dozen today. Jerusalem is like the Galápagos Islands of religion - you can't open your eyes without spotting an exotic creature.

It seems as if Jacobs relished in the attention he was getting, so I think that vanity might have had a bit to do with his quest, and not just attempting to understand the religious mindset.

There's almost always a church youth group at the soup kitchen. I have yet to see an atheists' youth group. Yeah, I know, religious people don't have a monopoly on doing good. I'm sure that there are many agnostics and atheists out there slinging mashed potatoes at other soup kitchens. I know the world is full of selfless secular groups like Doctors without Borders.

But I've got to say: It's a lot easier to do good if you put your faith in a book that requires you to do good.

Jacobs included the appropriate disclaimer, but doesn't seem to have really given it the weight it deserved. Us atheists and agnostics don't form atheist/agnostic charity groups because it's a bit superfluous. If you want to help feed people, you don't start an atheist soup kitchen, or an agnostic food drive. You start a plain old soup kitchen, or a plain old food drive. Or, more often, you go volunteer at one of the the charities that's already been founded.

As far as youth groups, hasn't Jacobs ever heard of the Scouts or Campfire? I know, technically Boy Scouts have to be religious, but it's mostly a secular organizations, with little focus on religion. I know that as a kid I did a lot more charity work with my Boy Scout troop than with my church youth group. My daughter is in Girl Scouts, which in their policy officially declares the organization to be secular ("Our movement is secular and is founded on American democratic principles, one of which is freedom of religion.") My daughter has done quite a bit of volunteer work through Girl Scouts.

As another anecdote, my wife and I volunteered a few times to go on a medical mission trip to Guatemala. And I'd say that 1/4 to 1/3 of the volunteers were non-believers, which is about what you'd expect if Christians and non-believers were helping equally (actually, us atheists were over represented compared to the general population, but that's not all that unexpected for such a small group size).

Jacobs can say that it seems easier to do good if you put faith in the Bible, but I'm not sure that reality agrees with him.

At one point, he described his reaction to attending an atheist meeting.

Ken has, in fact, boosted the group's membership and started some programs. But go to an atheist meeting, and you'll see why the religious lobby doesn't have to worry about the atheist lobby quite yet. You'll see why there are no soaring atheist cathedrals and why hotel room night stands don't come with a copy of Why I Am Not a Christian by Bertrand Russell in the top drawer. It's hard to be passionate about a lack of belief.

Well, yeah. The only reason why atheists are so vocal is because of the pernicious influence of religion in our society. As soon as religion stops being such a problem (i.e. outlawing homosexual marriage, trying to get creationism taught in schools, the de facto requirement that political candidates are religious, etc.), we atheists won't have so much to complain about. Like Thomas Jefferson said, "It does me no injury for my neighbor to say there are twenty gods or no God. It neither picks my pocket nor breaks my leg."

Now that I'm an atheist myself, I have no desire to go to a building just to celebrate my non-belief. I'd rather be productive. I like going to museums to learn more about the world, going to parties to enjoy time with my friends, going to my daughters school pageants. It seems silly to even think about atheist cathedrals.

In another section, he described his aunt and uncle becoming religious for the benefit it would give their children, and contemplated it for himself.

They explored several religions, including Hinduism, but ended up diving into Orthodox Judaism, since they were born Jewish.

They didn't become ultrareligious because of a charismatic leader or the truth of the Bible - they did it for the structure. And now their kids have grown up into responsible young adults...

Would I rather have Bart Simpson or one of the Flanders kids? A couple of years ago, I would have chosen the loveably spunky Bart. No question. But nowadays, now that I have my own three-dimensional son, I'm leaning toward the Flanders progeny. Yes, they may be a little creepy, they may sing loud songs about Noah's ark, but at least you know they won't spend their free time burning down the cafeteria or skateboarding off a canyon. I'd sacrifice some individuality for the knowledge that my son will outlive me.

Perhaps it's because I place such high value on truth and honesty, but this is one of the reasons I hate most for being religious. If you think God is real, and you believe all the consequences spelled out in the Bible, then it makes perfect sense to go to church and raise your children in that environment. But if you don't believe, why would you raise your kids to believe in falsehoods? It's such an intellectually dishonest position.

Besides, this is a false dichotomy. Not being religious doesn't mean behaving like Bart Simpson. You can raise your children to think about other people, and think about the consequences of their actions, without ever bringing up religion.

Attempting to follow all the rules of the Bible includes the first commandment. Jacobs tried to pray to God, which is understandably difficult for an agnostic. He had varying levels of success, depending on the day. In one passage discussing his prayer, Jacobs made a very good point.

I even find myself being skeptical of those times when my heart was near to God in the last few months. Perhaps it was an illusion. If I prayed to Apollo every day, would I start to feel a connection to Apollo?

This is a line of reasoning that I don't think enough people explore. I noticed it especially the last time I went to a mass - how much reinforcement there was to continue believing, and how hard it would be to break that cycle when you do it every week.

At the back of the book, there was an interview with Jacobs. I'm assuming that this interview was only in the paperback edition, and not the hardcover.

It was a life-changing and perspective-changing year. In the end, I became what a minister friend of mine calls a "reverent agnostic," which is a phrase I love. Because whether or not there's a God, I believe in the idea of sacredness - that rituals can be sacred, the Sabbath can be sacred, and there's great importance to them. So I'm still agnostic, but a deeply different kind of agnostic.

In some ways, I can appreciate this view. The universe is an awesome place, and we're such tiny parts of it. There are a great many things that inspire me, or fill me with a sense of reverence. However, you have to be careful when it comes to 'sacredness'. Too often, when people put something in the category of the sacred, it becomes beyond reproach, above criticism, unassailable. Nothing deserves that level of immunity, because it's possible that we could be wrong about anything.

It also risks taking those concepts to extremes. Jacobs may consider the Sabbath sacred, but others have taken it so far to where they worry about whether or not they can flip a light switch, and whether the spark that might happen should be considered lighting a fire.

As for lessons I learned, perhaps the biggest was 'Thou shalt not stereotype.' Every preconception I had was smashed when I actually spent time with these groups. I had some very narrow notions about evangelical Christians before the year. But I found it's such a varied movement that you can't make a sweeping gneralization about it. For instance, I met an evangelical group called the Red Letter Christians. Instead of focusing on, for instance, homosexuality, the Red Letter Christians stress the literal words of Jesus and his teachings on compassion and peace.

This is a very good lesson, I think, for two reasons. First, taking Jacobs at his word, it shows the dangers of stereotyping. I have friends with all different types of religious beliefs, from atheists like myself to young earth creationists. People can get so caught up in religion that they forget that it's just one aspect of our lives. There's so much more that we do, that defines who we are, that it's easy to get along with someone while still disagreeing over religion.

On a more cynical side, though, Jacobs' observation reveals how people who do bad things aren't the evil villains of comic books. He discussed his visit with Jerry Falwell, and how friendly the man was in person, and how mundane the church service was. But don't forget that Falwell founded Liberty University, and co-founded the Moral Majority. The people in those organizations may have good intentions, but look at all the harm they've caused. To quote a religiously themed cliche, "The road to Hell is paved with good intentions."

Q: Are you going to raise your sons differently?
AJ: After the year, my wife and I decided to join a synagogue in our neighborhood. Granted, it's a reform temple and we don't go very often. (But I do pay the annual fees. Which, from the letters they send, is a very important part). We're going to send our sons to Hebrew school. I don't care whether they become Hitchens-like atheists or believers. As long as they're good people, I'll be happy. But I thought it was a good idea to give them a basis in religion, so they'll know what they're accepting or rejecting.

I already discussed above why I don't think you should raise your children to be religious if you're not a believer yourself. It's dishonest. But that's not exactly what Jacobs is saying here. It sounds like he's trying to expose his children to religion so that they can make their own choice. But, as I'm sure is glaringly obvious to anybody reading what he wrote who isn't Jewish, he's given them a pretty limited view on religion by sending them to a Hebrew school. Why not send them to Catholic school, or a Protestant school, or a Hindu temple, or a madrasah? That's one of the problems I've noticed with many people. When they say they want to expose their children to religion so that their children can have their own choice, those people usually mean their own religion, or the religion of their ancestors if they're no longer particularly religious themselves. It's hardly ever meant to expose them to the full spectrum of religious views.

On the other hand, given how important religion is in contemporary society, it's probably not such a bad idea to expose children to it in some form, so that they'll have some type of understanding of that mindset.

So, after the whole year was over, what was Jacobs' conclusion on following the Bible literally?

Q: How did it change your view on religion? AJ: In several ways, I feel I better understand some of the great things about religion and have incorporated many of them into my life. I also learned that interpreting the Bible too literally can be dangerous. I learned that you can't follow every single rule in the Bible. There is a certain amount of picking and choosing. And fundamentalists call this cafeteria religion and they mean it as an insult. But I say: What's wrong with cafeterias? I've had some delicious meals at cafeterias. It's all about choosing the right parts of the Bible, the ones about compassion and helping your neighbor. I also learned that even the rules that seem crazy at first can have a deeper meaning.

So, after actually reading the entire Bible, and trying his best to follow it literally, he concluded that it just wasn't possible. I don't think that's much of a surprise to anyone else that's actually read the Bible.

His approach of picking the best parts sounds reasonable to anyone who's not religious themselves, but it kind of removes the whole authority of the Bible, doesn't it? Especially considering how he's contemplated using the Bible as a rulebook for his kids so that they grow up with some structure - how can you justify using it as an authoritative source when you throw out all the rules you don't like?

Anyway, as I said at the beginning of this review, I've focused on the parts of the book that I disagree with the most. Overall, it's an interesting look at just what it takes to follow the Bible literally, along with some thoughtful discussion on religion in general.

Further Reading:

• Debating The Year of Living Biblically - A dialogue on Slate
  
• Interview with A.J. Jacobs by The Friendly Atheist
  

Posted by Jeff on Friday, Jul 30 | Permalink | Comments (31) | TrackBacks (0)

I know I don't have many regular readers, but I get a few passers by. So, I figured I'd post a strange request:

Please recommend to me the most convincing creationist book or other resource to read.

I'll be honest. I really, really doubt that creationism is correct (I put it on the same level as flat earthers), and I doubt that I will be convinced. I've followed the debate on Internet forums quite a bit, and I'm well familiar with the standard creationist canards. However, in the interests of being open minded, I figured I ought to give creationism its best chance, and go check out whatever is recommended as the best source to convince me that it's true.

I've already wasted time on two creationist sources - the book, God: Or Gorilla (which was written back in the '20s, so I'll give creationists the benefit of the doubt and assume that they've come up with better arguments by now), and the 'documentary', Expelled (which was little more than propaganda). Neither was very convincing at all. While God: Or Gorilla was somewhat entertaining, Expelled pissed me off with its exploitation of the memory of Holocaust victims. So, I don't want to just go off willy nilly reading creationist material if it's going to be as bad as those two sources, which is the reason for this request.

I'd really prefer if the resource was a book, since it gives me a clear goal of what to read. Websites are rather nebulous. And please don't be a smart alec and recommend Genesis. First of all, I've already read it plenty of times, so it won't be anything new. But mainly, I'm looking for some actual evidence.

Leave any recommendations in the comments. Since I get so little traffic, I'll leave this thread open for a while before I go out and buy any books.

2010-08-06: A friend of mine who's a creationist has recommended Thousands, Not Billions: Challenging the Icon of Evolution, Questioning the Age of the Earth. If I don't get any comments here within the next couple weeks recommending anything else, that's the book I'm going to read. It will be quite a change of pace considering the book I'm currently reading - Archaeopteryx: The Icon of Evolution.

2010-11-30 I went and ordered the book a couple months ago, read it, and came up with my review. To summarize, the book didn't convince me that creationism was valid. If you want to read why, go take a look at the review, in two parts:

• Part I
• Part II

Posted by Jeff on Friday, Jul 9 | Permalink | Comments (27) | TrackBacks (0)

It is interesting to contemplate a tangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms, so different from each other, and dependent upon each other in so complex a manner, have all been produced by laws acting around us. These laws, taken in the largest sense, being Growth with Reproduction; Inheritance which is almost implied by reproduction; Variability from the indirect and direct action of the conditions of life and from use and disuse: a Ratio of Increase so high as to lead to a Struggle for Life, and as a consequence to Natural Selection, entailing Divergence of Character and the Extinction of less-improved forms. Thus, from the war of nature, from famine and death, the most exalted object which we are capable of conceiving, namely, the production of the higher animals, directly follows. There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.

So ends Darwin's Origin of Species, giving the inspiration for the title of Carl Zimmer's latest book, The Tangled Bank: An Introduction to Evolution. It is described as a textbook on evolution for non-biology majors, and it is very good.

The term, 'evolution', is pretty broad. In general, when people talk of biological evolution, there are two broad categories they're referring to. The first is the concept of common descent with modification - that all life on this planet is related, and that populations of organisms change over time. The second is the theories describing how that works, with natural selection being the most famous. Pretty much every book that covers evolution will cover both areas to some extent, but often times they will focus on one area over the other. The Tangled Bank covers more of the latter subject. Of course, it uses examples, but it is more about how evolution works rather than a fossil by fossil account of the evidence for common descent (for that type of book, read Donald Prothero's Evolution: What the Fossils Say and Why It Matters - also, realize that there's much more evidence for evolution than just fossils).

Let me give an example of one of the concepts I learned about - Hardy-Weinberg Equilibrium. This term is probably familiar to biology majors, but it's not something us non-biologists generally read about in most popular books or magazine articles on evolution. The concept has to do with allele frequency. As a refresher, an allele is a variation of a gene. Think back to your high school biology class, and the genetic experiments of Gregor Mendel. For example, Mendel discovered a certain gene* that controlled pea color - one version would make them green, while the other would make them yellow. Each version is called an allele. Remember further, that us eukaryotes carry two copies of a gene (actualy, at least two - it can get a bit more complicated than this). So, individual plants in a population of all green peas might all carry two copies of the green allele - GG, and individual plants in a population of all yellow peas might all carry two copies of the yellow allele - YY. Now, if you were to bring those two populations together, the alleles woud start mixing, and you'd end up with three different combinations that the plants could have - GG, YY, and GY (GY and YG are the same thing). What Hardy-Weinberg equilibrium tells us, is that according to just random mating and chance distribution, these allele combinations should all be present in certain ratios. In this example, half of the plants would likely be GY, one quarter would be GG, and the remaining quarter would be YY. But what if you checked up on your pea population, and found that it didn't match the Hardy-Weinberg equilibrium? What if less than a quarter of the plants were GG, and more than a quarter were YY? Well, then we could conclude that something about the Y allele was advantageous to the plants, and that natural selection was pushing the population to have more plants with the Y allele.

This concept of Hardy Weingberg equilibrium can be applied to more complicated scenarios. It doesn't have to be just two alleles, and the initial distribution doesn't have to be 50/50. However, for any combination, the Hardy Weinberg equilibrium is the distribution you'd expect if there weren't any natural selection, and measuring how much the actual distribution varies from the Hardy Weingberg equilibrium is a measure of how strong the selection is.

To me, that's a pretty interesting concept, and it wasn't something I'd given much thought to before reading Zimmer's book. However, the book didn't go into much more detail than what I just gave in my summary. If you're not of a technical bent, that may be all you need. I realize that Zimmer's goal was to provide a book for non-biology majors, so maybe that's all the detail he felt was necessary. However, to someone like me, who may not be a biology major but wouldn't mind seeing a little light math, Zimmer's explanation was a little too superficial. I mean, if you follow that Wikipedia link I provided and read the explanation of Hardy Weinberg equilibrium, the math isn't all that hard. It's just a bit of algebra. Maybe as an engineer who works with equations all day long I'm a bit biased, but it's not as if you need to understand any calculus or differential equations to follow the basics of Hardy Weinberg equilibrium.

I can't discuss this book without mentioning the illustrations. Practically every page of the book has a figure or a graph. I'm sure that the printing cost associated with this contributed to the $50 price tag for the book, but it really makes it easy to understand certain concepts that would be difficult to get across with just words.

This book was published right around the same time as Richard Dawkins' The Greatest Show on Earth: The Evidence for Evolution, so there were inevitably comparisons. But the truth is that they're just not the same kinds of books. In my discussion above on the broad meanings of evolution, I said that Zimmer's book covered more the theories of evolution. Dawkins' book was more of a look at the evidence itself. Zimmer's book was a textbook with color illustrations on each page, while Dawkins' book was a popular book with few illustrations. Comparing the two is comparing apples to oranges.

If you'd like to get more of a taste of the book, I've found two excerpts available for download online. Chapter 1, Evolution: An Introduction is availabe from Carl Zimmer's own site. Chapter 10, Radiations and Extinctions is available from the National Center for Science Education. You can also read Zimmer's announcement of the book on his blog, to hear his intentions in his own words.

All in all, The Tangled Bank was very good. It was a nice broad introduction to many of the theories and mechanisms of evolution, but without getting too technical for those of us that don't plan to go into careers in biology. Unfortunately, being a textbook, it's a bit pricey. You may try going to your library to check it out, find it used, or maybe be lucky enough to be able to borrow it from a friend. However you manage to get your hands on a copy, I definitely recommend this book.

*Mendel's insight was that there were units of heredity, now known as genes, as opposed to the prevailing concept at the time of blending inheritance, but he didn't actually know the mechanism responsible. It wasn't until later that other scientists discovered that genes were contained on chromosomes, and later yet that scientists discovered that chromosomes were made of DNA.

Posted by Jeff on Thursday, Jun 17 | Permalink | Comments (27) | TrackBacks (0)

Guns, Germs, and Steel: The Fates of Human Societies is a Pulitzer Prize winning book by Jared Diamond. To quote from the book itself, it is "A short history about everyone for the last 13,000 years." Diamond has attempted to explain why world history has taken the course it has. But he's more interested in large scale trends and causes, as opposed to battle by battle or even war by war tracking of history. Or, to put it another way, he was taking a more scientific approach to history, as opposed to just stamp collecting. Wikipedia has a good overview of the book, so I'll only present a brief summary here.

To use an example, we all learned in school of the European conquest of the Americas, even though the Europeans were vastly outnumered. We've been taught many of the factors that lead to that result, most notably the superior weapons technology of the Europeans, horses, and the diseases that Europeans brought with them. Diamond noted all these proximate causes (and a few others), but then moved on to ask why the Europeans had developed those advantages, and not the other way around. Why hadn't Motecuhzoma sent ships to conquer Spain?

According to Diamond, much of the advantage of certain regions was a result of geography and the indigineous plants and animals. To help support his case, Diamond looked at native plant species around the world, how nutritious they were, and how easily they could be domesticated. Wheat, for example, is a very nutritious crop, with a fairly high protein content for a plant. It required only a single mutation in wild wheat, inhibiting the seeds from falling off the crop when ripe, to make it suitable for agriculture. Teosinte, by comparison, required many more mutations to become domestic corn (maize), which isn't as nutritious as wheat. As it turns out, Eurasia has a greater number of nutritious, easily domesticated plants than any other region.

Eurasia also had a higher number of potential livestock candidates. In many regions of the world, the Pleistocene extinction event killed off most large mammals at the end of the last ice age (there is debate over the cause of this extinction, but that's largely irrelevant to Diamond's hypothesis). If you don't have large wild mammals, you can't domesticate them into livestock. But you can't just domesticate any large animal. In this section of the book, Diamond quoted Tolstoy, "Happy families are all alike; every unhappy family is unhappy in its own way." There are many traits an animal has to have to make it suitable for domestication (diet, behavior, lack of aggression, social structure, etc.), but missing any one of them would make an animal unfit for domestication. Diamond used this reasoning to show why, for example, zebras weren't domesticated in Africa like horses were in Eurasia, or why bears or rhinos weren't suitable to domesticate for food or as draft animals.

Diamond went on to argue how differences in geography allowed agriculture and domestic animals (referred to collectively as food production) to spread more easily in some regions than others once they had been developed. Eurasia, without any great barriers such as deserts, and with an east-west axis that meant the climate was more similar along its breadth, facilitated this spread more so than other regions.

Once regions had developed food production, they could maintain higher population densities. Initially this gave them a military advantage just through shear numbers. But eventually, by providing for an artisan class that didn't have to grow its own food, it led to technological advantages, as well. The high population densities, along with domestic animals, also contributed to those regions having endemic diseases that didn't exist elsewhere.

As an example of how Diamond was attempting to explain the grand patterns in history over tens of thousands of years, he pointed out that someone could ask why, out of all the areas of Eurasia, Western Europe currently dominates the world stage, and not Eastern Asia. He stated that this simply might be a short term 'blip', and not part of the long term trend (just look at the resurgence of modern China).

As I said, this is only a brief summary of the book. Diamond had many more reasons and examples that he used to support his hypothesis.

Some parts were more convincing than others. It also didn't help that in a few examples he brought up that I already knew a bit about, I saw some mistakes. For example, when discussing ancient human history, he compared the Out of Africa hypothesis to the multiregional hypothesis. The weight of evidence strongly favors the 'Out of Africa' hypothesis, but Diamond seemed a little more ambiguous in the book. In another section, discussing why cultures might be resistant to adopting certain technologies, he brought up the old QWERTY/DVORAK controversy, claiming that DVORAK is clearly superior to QWERTY, but market forces have kept it from being adopted. This is an old urban myth that isn't true. There haven't been many actual studies comparing the two keyboard layouts, and the studies that have been done don't show a very big advantage of one design over the other (certain advantages of each layout are offset by different advantages of the other layout).

Overall, I thought the book was very interesting, and that Diamond did a good job of presenting his case. I'd definitely recommend it.

Update 2010-03-29 - Slightly revised wording in 4th from last paragraph.

Posted by Jeff on Friday, Mar 26 | Permalink | Comments (28) | TrackBacks (0)