Tangled Bank Nr. 15

It's the day after the first Tuesday in November, and you know what that means. Countless millions -- in America and around the world -- are waiting eagerly to learn just one thing: What will I find along the Tangled Bank today? Fret no longer, your patience has been rewarded. It's my privilege to take a turn as host to this biweekly science and medicine-focused 'carnival of the vanities'.

As both PZ Myers (who will, I hope, find it in his atheist heart to forgive me for calling him 'The Pope of the Tangled Bank') and I are partial to invertebrates, it's appropriate that this edition of TTB kicks off with a contribution from The Raw Prawn. The Prawn's Reena Ganga tells us about India's burgeoning medical tourism industry. Sounds like a good deal to me: take in the Taj Mahal in the morning, and still have time to be on the table for your heart transplant in the afternoon.

Chris Clarke writes Creek Running North (again, an appropriate image for the Tangled Bank, n'est-ce pas?). Here he records his thoughts during a hike somewhere in the western United States. He achieves communion with the distant Permian past, quite literally: he is covered in its dust. Well, dust we are, and unto dust shall we return, of course. It was no different in Permian times, but the great Permian extinction made sure that lots of organisms returned to dust in very short order. Chris thinks about why this might have happened, and in mulling over mass extinction and the decline of biodiversity in our own era gets a bit depressed. He should cheer up: his post also describes his garden, which began simply enough as a plan for putting some plants in the ground but has evolved (if you will) into a fascinating cooperative venture between Chris and Mother Nature. Even as we race inexorably towards extinction, there's some consolation in that, surely.

I'm sorry to have to dampen the mood of the party by mentioning creationism, presumably a bugbear for all regular wanderers along the Bank. But there's good reason to do so. As even a brief visit to his main website, An Evolving Creation, makes clear, Jeremy Mohn is a committed Christian who takes scripture seriously. He's also a biology teacher who knows that creationism -- whether in its traditional troglodytic form or wearing the stolen labcoat of 'intelligent design' -- is atrocious pseudoscience. Equally interesting from a believer's perspective, he knows it is atrocious theology as well. Really, there shouldn't even need to be a debate over creationism. Most believers have no trouble reconciling their theism with science; many scientists are themselves believers. Still, to listen to the noises coming out of some American states, you'd think the Evil Darwinists are regularly feeding Christians to genetically-modified lions. It's important to hear scientifically knowledgeable believers reminding their fellow theists that evolution doesn't threaten their beliefs -- indeed, it should deepen them. Here, Jeremy gives us some thoughtful reflections on what we mean by 'science'. Very useful stuff if you ever find yourself talking to a creationist who doesn't understand the distinction between philosophical and methodological naturalism (or who, more vulgarly, tells you that evolution is 'just a theory').

But let's see how that 'theory' works out in practice. At Pharyngula, PZ Myers reports on a recent paper in Nature by O. Jaillon et al. We've all seen those huge glossy fold-outs in Nature showing genomes as swatches of colour. I can't make head or tail of the things myself, but Jaillon and colleagues make sense out of two of them at once. They have published a draft genome for a freshwater pufferfish, Tetraodon nigroviridis. And they've gone on to compare it with our own genome. As you'd expect, there are some differences. One difference you might not expect is that, unlike our own 'junk DNA'-bloated genome, T. nigroviridis's is lean and elegant. (The pufferfish genome, if you will, is Linux to our Windows.) But Jaillon et al. sift through the junk and find the syntenies lurking beneath the surface -- regions of DNA that have remained preserved across millions of years of mutation and speciation. Using these syntenies, they construct a putative genome for the last common ancestor of pufferfish and people. A remarkable chapter added to the book of knowledge; or, as PZ puts it, 'kick-ass, far-out, mega-cool'.

Enough of pufferfish, those distant cousins. Let's look now at animals much more closely related to us: dinosaurs. Sadly, most of them are long dead. One line of Euraptoridae, though, has not only survived but flourishes to this day. We call them 'birds'. There are some ten thousand species; the website 10,000 Birds records one couple's ambitious project of seeing them all. Mike Bergin explains why it's sometimes hard to know which species you're looking at. He describes two raptors (in the more modern sense of the term), the sharp-shinned hawk (Accipiter striatus) and Cooper's hawk (A. cooperii). Different species, yes; but only just barely different. Many birders can't distinguish them, Mike reports, and even old raptor hands can expect to get it wrong from time to time. The differences are subtle. The most obvious is size: sharpies are smaller. But the maximum of their size range overlaps with the minimum of the Cooper's hawk. Spotting the difference involves picking up on a number of very faint clues; tough enough in the best of situations, and frightfully difficult when the subject you are observing is on the wing. Mike offers guidance to his fellow birders (I am going to have to forward this to my father, himself a devoted raptorophile). Though Mike's article is primarily intended as practical advice for the naturalist in the field, it stirs up thoughts familiar to anybody with a penchant for systematics: what makes two animals conspecifics, and what makes them members of different species? And how did they get that way?

Hawks are fierce and impressive and all, but I'm not sure we'd call them 'cute'. So, you want Cute? Radagast will give you Cute. Over in Rhosgobel, Radagast has adopted some baby mice. First we see them as infants, blind and bald but insufferably Cute for all that. (I hope it will not horrify you too much to learn that some tarantula-keepers like to feed their hairy eight-legged brutes with mice at this stage of development.) Radagast's baby mice seem to have escaped the giant arachnids, though; here they are at 17 days, and the Cuteness has reached such dangerous levels that your monitor might just melt down into a warm sweet sticky goo. So, is this all just so much Cutenessblogging, a rodent counterpart to Kevin Drum's adorable fluffy kittens or PZ Myers's adorable scaly Leanchoilia? Not at all. Like any good scientist, Radagast forms a hypothesis (here, about fur colour patterns) and observes the results to see if it pans out.

Finally, there seems to be a Tangled Bank tradition of including a post of one's own. (All right, maybe there isn't such a tradition; if not, I've just invented it.) No earth-shattering scientific revelations here; just a tale of bittersweet romance and death.

Thanks for visiting; it's been a pleasure to have you. Tune in two weeks from now at Rhosgobel, where Radagast will bring you an all-new action-packed edition of Tangled Bank -- and, perhaps, a new batch of baby mice. (And do consider sending Radagast something of your own for inclusion.) Until then, farewell, and may the frequency of your alleles in the overall population increase from generation to generation.