Why are flounder funny looking?

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The other day, I was asked a simple question that I knew the answer to, right off the top of my head, and since I’m nothing but lazy and lovin’ the easy stuff, I thought I’d expand on it a bit here. The question was, “How do flounder get to be that way, with their eyes all on one side of the head?” And the answer is…pedantic and longwinded, but not too difficult.

The Pleuronectiformes, or flatfish, are a successful teleost order with about 500 known species, some of which are important commercially and are very tasty. The key to their success is their asymmetry: adults are camouflaged ambush predators who lurk on the sea bottom, taking advantage of their flat shape to rest cryptically and snap up small organisms that wander nearby. They lie on their sides, and have peculiarly lop-sided heads in which one eye has drifted to the other side, so both eyes are peering out from either the left or right side (which side is consistent and characteristic for a particular species, although there is at least one species with random assignment of handedness to individuals, and mutant strains are known in others that reverse the handedness.)

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Ancient rules for Bilaterian development

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Assuming that none of my readers are perfectly spherical, you all possess notable asymmetries—your top half is different from your bottom half, and your front or ventral half is different from you back or dorsal half. You left and right halves are probably superficially somewhat similar, but internally your organs are arranged in lopsided ways. Even so, the asymmetries are relatively specific: you aren’t quite like that Volvox to the right, a ball of cells with specializations scattered randomly within. People predictably have heads on top, eyes in front, arms and legs in useful locations. This is a key feature of development, one so familiar that we take it for granted.

I’d go so far as to suggest that one of the most important events in our evolutionary history was the basic one of taking a symmetrical ball of cells and imposing on it a coordinate system, creating positional information that allowed cells to have specific identities in particular places in the embryo. When the first multicellular colony of identical cells set aside a particular patch of cells to carry out a particular function, say putting one small subset in charge of reproduction, that asymmetry became an anchor point for establishing polarity. If cells could then determine how far away they were from that primitive gonad, evolution could start shaping function by position—maybe cells far away from the gonad could be dedicated to feeding, cells in between to transport, etc., and a specialized multicellular organism could emerge. Those patterns are determined by interactions between genes, and we can try to unravel the evolutionary history of asymmetry with comparative studies of regulatory molecules in early development.

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The Big Bang for Dummies

I’m not a cosmologist and I don’t even pretend to be one on the internet, but as an evolutionist I hear far more about the Big Bang from creationists than I should…and it’s everything from the Big Bang never happened to the Big Bang disproves evolution, and often both opinions are held by the same person, who will often also tell me both that the Cambrian is proof of sudden creation and that the earth is less than 10,000 years old (consistency is not a quality valued by most creationists). It’s therefore rather handy to have a summary of misconceptions about the Big Bang all in one place.

Flap those gills and fly!

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I am going mildly nuts right now—somehow, I managed to arrange things so multiple deadlines hit me on one day: tomorrow. I’ve got a new lecture to polish up for our introductory biology course, a small grant proposal due, and of course, tomorrow evening is our second Café Scientifique. Let’s not forget that I also have a neurobiology lecture to give this afternoon, and I owe them a stack of grading which is not finished yet. I’m really looking forward to Wednesday.

Anyway, so my new lecture for our introductory biology course is on…creationism, yuck. What I’m planning to do is to describe some of the most common creationist arguments and then give a biologist’s rebuttal. Creationism is really a waste of our class time, but using it to explain some general concepts that any informed biologist should understand (and that the creationists, including Mike Behe, are astonishingly clueless about) will make it a little more productive, I hope. We’ll find out tomorrow.

One of the common creationist claims I plan to shoot down is the whole idea of “irreducible complexity” as an obstacle to evolution. I was going to bring up two ideas that invalidate it: the principle of scaffolding (which I discussed here), and exaptation, in which features evolved for some other purpose than the one that they play in an organism we observe today. I was looking for a good example, and then John Wilkins fortuitously sent me a paper that filled the bill (we evilutionists, you know, are sneakily sending each other data behind the scenes to help in our assault on ignorance. We’re devious that way.)

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Peter Doran in the NY Times

Peter Doran published a paper several years ago showing that parts of Antarctica were actually cooling, rather than warming—that there were local variations in temperature trends. This is not surprising. It’s also not surprising that he was quote-mined like mad by the global warming denialists. He has now written a calm, solid rejection of the misuse of his data in the NY Times.

Our results have been misused as “evidence” against global warming by Michael Crichton in his novel “State of Fear” and by Ann Coulter in her latest book, “Godless: The Church of Liberalism.” Search my name on the Web, and you will find pages of links to everything from climate discussion groups to Senate policy committee documents—all citing my 2002 study as reason to doubt that the earth is warming. One recent Web column even put words in my mouth. I have never said that “the unexpected colder climate in Antarctica may possibly be signaling a lessening of the current global warming cycle.” I have never thought such a thing either.

Our study did find that 58 percent of Antarctica cooled from 1966 to 2000. But during that period, the rest of the continent was warming. And climate models created since our paper was published have suggested a link between the lack of significant warming in Antarctica and the ozone hole over that continent. These models, conspicuously missing from the warming-skeptic literature, suggest that as the ozone hole heals—thanks to worldwide bans on ozone-destroying chemicals—all of Antarctica is likely to warm with the rest of the planet. An inconvenient truth?

This is great stuff, but anyone want to take any bets on whether the anti-scientific global warming crackpots will now extract that penultimate sentence and use it to urge easing the ban on fluorocarbon release?

Francis Collins, doofus for the Lord

I just watched the Francis Collins/Charlie Rose interview (it starts at about 35 minutes on that clip), and although I struggled manfully to appreciate the fellow’s accomplishments and status in science, I failed. All I could see is that he was illogical, irrational, and downright goofy—all the symptoms of a severe affliction with a bad case of religion. That video ought to be a warning to scientists: even a prestigious scientist can suffer Christian mind-rot.

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A simple story gets complicated

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People, scientists included, are always looking for simple, comprehensible explanations for complex phenomena. It’s so satisfying to be able to easily explain something in a sound bite, and sound bites are so much more easily accepted by an audience than some elaborate, difficult collection of details. For example, we often hear homosexual behavior reduced to being a “choice,” the product of a “gay gene,” a “sin,” or something similarly absolute and irreducible…suggesting that it is part of a diverse spectrum of sexual behaviors with multiple causes and that different individuals are different in their behaviors is almost certainly the more accurate description, but that doesn’t satisfy our need for straight, simple, linear causal mechanisms. This is true of most animal behavior, I think—you just can’t crunch it down to one single agent that drives much of anything.

I thought there was one excellent counter-example, though, one that suggested at least some complex behaviors might be reducible to a discrete source: the mating behavior of Microtus voles. It was such a simple, clean story; new results suggest that it was too clean, and that there’s much more to the behavior than was thought.

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Religious credulity and the recent spate of godly ‘science’

I usually like Cornelia Dean’s science reporting, but this recent collection of book reviews put me off from the opening paragraph. She begins with the tired old claim that “scientists have to be brave” to embrace religion. Malarkey. I’ve never heard a scientist bring up the subject of religion, pro or con, at a scientific conference or associated informal gathering. You can be as devout as you want to be with no risk to your professional career (you may even find yourself an icon for the compatibility of science and religion!), and as for your personal life, being religious in a country in which 90% of the residents self-identify as religious, and in which religiosity has become a defining character of our political leadership, is hard to characterize as boldly bucking a trend. The rest of the review is an exercise in credulity.

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