Told you so...

Guess what's about to make its way onto the MCAT, and into medical school curricula?

Stupid birds...

Someone should explain to the pied flycatcher that climate change is all in the liberal imagination.

Actually, an interesting look at how the flycatchers and other birds have been able to adapt their migratory cycles.

Mad cow

Transmissible spongiform encephalopathies like Creutzfeldt-Jakob disease in humans and bovine TSE, better known as mad cow disease, have certainly caused their share of misery, as well as capturing public attention. A new study appearing in Science, and appearing online at Science Express, describes the work of Ohio State's Jiyan Ma and his colleagues in which they have shown how normal proteins can be converted into prions, the causative agent of spongiform encephalopathies. Prions are abnormally folded proteins which stimulate the formation of other such proteins in the development of the brain disease. However, since the original description of prions in the 1980s it has been unclear how the process operates, with a major drawback being the inability of researchers to employ recombination techniques in the creation of infectious prions. That's exactly what Ma and his associates were able to do. Employing mouse proteins, they determined that it is through an interaction with lipids in the cell membrane that the protein is altered.

They were also able to induce TSE in laboratory mice, which developed TSE symptoms within a few months after recombinant prions were injected into their brains. (On a side note - I'm all for the ethical treatment of animals. I think work like this certainly fits that description). This certainly represents a major step forward in our understanding of prion disease.

Now, for those of you that might have wanted a less dry treatment of mad cow disease - hope this is warped enough for you...

Excuse me? I didn't catch that last part...

Ok, here's the deal. We're gonna stop growing pine trees, see? And we're gonna replace the pine trees with these genetically engineered eucalyptus trees from Australia, see? And we're gonna grow these trees really fast and harvest 'em and use 'em to produce biofuels, see? And we can grow 'em here because they're genetically engineered to not freeze, right? And we're gonna plant these genetically engineered eucalytpus on, I don't know, maybe 10 million acres across the South. And, get this cause it's like the the best part, we know that these trees won't cause any problems because they've also been genetically engineered to produce an enzyme that destroys the reproductive parts of the tree.

Kudzu says "Hi".

tgif...

Looks like Friday is now meeting day. Some time this weekend. Maybe.

A thought. It's not over in Haiti. The news media will back off, because the story's not so dramatic - but a lot of lives hang in the balance. And, chances are, you got just paid. Consider hittin' it one more time.

Some weekend music. Enjoy.

The Red Queen

Why sex? Because, if we stop, they'll catch us. More to come.

Remember...

Thursday's lab day.



But, here's a little something from the Wayback Machine.

"Help me, Doctor! Please!"



Several times, I've taught a class in our Honors Program in which we investigate the influence of Charles Darwin on farflung fields ranging from the sciences to literature to economics. Here's an interesting little tidbit in that arena. Brian Regal, an assistant professor at Kean University in Union, NJ, believes that Charles Darwin has pretty much single-handedly killed off the last remaining werewolves. His idea, presented last summer at meeting in the UK, is that the development of the theory of evolution by natural selection has changed the nature of our boogymen. Throughout human history, the werewolf legend has been a part of our night terrors. Not so much any longer. Regal believes that this is partly due to the evolutionary distance between canines and primates, allowing Darwin to transform the werewolves of our heritage into more evolutionarily suitable analogues like yetis, sasquatches, and skunk apes.

I'm not sure I buy that. I'm not convinced that purveyors of horror spend a lot of time thinking about the genetic similarity of their chimaeras. Remember Jeff Goldblum's 1986 entomological moment? Of course, that was a remake. But what about the recent vampire craze? Most mammalian cladograms wouldn't put the chiropterans any closer to primates than the carnivores.

No, I suspect that Dr. Regal has hit on an interesting idea that doesn't really shed a lot of light on our cultural evolution. I only wish that the general public knew enough about biology to watch a monster movie and say, "Wait a minute.... that doesn't make sense - you know, in an evolutionary context."

A dinosaur of a different color...

If you're at all into documentaries or the Discovery Channel, you've watched scenes like this...



...and probably made the assumption that the depiction is fairly realistic. Truth is, we've learned enough about the skeletal structure of dinosaurs and other prehistoric species that we can render a picture that's accurate in size and shape. Even aspects of how they might have moved is revealed from an analysis of structure. The one area, though, where images like these remain highly speculative is in coloration. Our best guess of the color of a T. rex has been largely that - a guess. ScientificAmerican.com tells us about a new study that will appear in the January 28 issue of Nature that may fill in some of the missing hues. Examining 125 million year old fossils of dinosaur feathers under a scanning electron microscope,researchers have been able to identify organelles responsible for pigment production. Applying what we know about pigments in living birds and reptiles, they are able to make an educated guess about what the fossilized creatures might have looked like.



Among the animals examined was Sinosauropteryx, a turkey-sized, feathered predatory dinosaur. The analysis revealed that the little guy had a tailed marked by "russett, gingery" bands, according to the University of Bristol's Michael Benton.

The dinosaur colorists owe a debt of gratitude to Jakob Vinther, a Ph.D. student in paleontology at Yale. Vinther noticed that fossilized melanosomes in the ancient squid that he was studying looked identical to those in living squid. He speculated that this might be true of melanosomes in other structures, and the work took off from there. Of course, there's still a lot of work to be done, and still a lot of conjecture. Still, we may be headed toward more realistic images of the animals that we've all been fascinated with since elementary school.

This probably shouldn't surprise me....

...but it does. It's better to run barefoot.

Convergence in bats and whales...

Dolphins aren't the only mammals that employ echolocation for navigation and prey detection. It's a trait that's also well developed in bats. It's clearly convergent, as the ancestry of the two groups is quite different. However, new research appearing in Current Biology tells us that echolocation in bats and whales arises through nearly identical genetic changes. A gene known as prestin has evolved along the same lines in both the bats and in the dolphins examined. As a result, if we examined the phylogeny of the groups based on this gene alone, they would appear to be closely related when, in fact, they aren't.

The results suggest that, when a mammal finds itself in an environment where the ability to hear high frequency sounds and utilize them for echolocation, there may be only a very few genetic approaches to solving that problem. Perhaps, only one.

We know that there was at least some overlap between modern humans and neanderthals in western Europe around 40,000 years ago, but that the Neanderthals eventually were replaced or assimilated. However, there is strong evidence of the existence of a Neanderthal refuge in in the region of modern-day Spain and Portugal for several thousand years after they had vanished from the rest of Europe. What has been uncertain is exactly how long these populations persisted, and what ultimately became of them. Science Daily reports on new research by Joao Zilhao and his team which indicates that modern humans were established in the region by 37,000 years ago, suggesting that the Neanderthal refuge had declined by that time. This means that the Neanderthals persisted in the region for only about 5,000 years, considerably less than the 15,000 or so that had been previously suggested.

There's another interesting implication of this find. A 30,000 year old fossil find of a chlid in Portugal demonstrates some previous features, and there have been some rather off-the-wall suggestions that this might be evidence of hybridization between a relict Neanderthal population and modern humans. Doesn't look like the new time frame allows for that possibility.

Brains - big and little

Of course, Brett's big brain didn't do him much good. But, in the normal course of events, isn't a big ole brain the way to go? We humans are certainly proud of our large reasoning organs - couldn't be biased, could we? A new paper in the online journal BMC Biology (and referenced at ScientificAmerican.com) takes a look at brain/body sizes over primate history and concludes that evolution hasn't always trended toward the giant economy size.

That conclusion is particularly significant in our interpretation of one little guy - the hobbit. No, not Frodo. And actually, not a guy either. The small female hominid discovered in Indonesia in 2004 and christened Homo floresiensis by her finders and the "hobbit" by the popular media has a brain size about 1/3 that of a modern human. Since the fossils are only about 13,000 years old, the tiny-brained hobbit and her ilk would have had to coexist with their big-brained cousins for almost 200,000 years. A number of ideas have been advanced to explain the find, with some contending that H. floresiensis had adapted toward a smaller size because of their island habitat and others claiming that the specimen simply represents a malformed individual. Still others have suggested that the little lady is the culmination of an ancient lineage that, for whatever reason, had evolved toward smaller brain and body size.

The researchers, led by Cambridge's Stephen Montgomery, examined sizes of bodies and brains of 50 primate species, 35 living and 23 extinct, and concluded that, while there has been an overall trend toward increased brain size, there are certainly exceptions in some lineages. The earliest primate brains were little more than a tenth of a gram. The Cadillac today, of course, is the human brain which averages around 1.3 kg, and over the extent of primate history there has been an average increase in brain size in the neighborhood of 2.5% per million years. However, this is by no means universal, and decreases are the rule along some lines. In fact, the researchers conclude that the decrease in brain size seen in our little hobbit friends are "not unusual in comparison to these other primates."

So, good news for the little lady. Still in the club. Take your little hat off and take a bow.

juicy links.

Professor Baba Shiv at Stanford University may be able to tell you why a night of cramming may make you more likely to eat junk food:
Willpower And The 'Slacker' Brain - NPR

And some new info on the origins of amputation from the Times Online, courtesy of Jordan Blaize:
Evidence of Stone Age amputation forces rethink over history of surgery - Times Online

Deadbeat moms

Thanks go to Kyle for bringing to my attention an interesting story about about the ongoing evolutionary wars out there (the ones between animals - not the ones between people). In this case, the strategy is brood parasitism, in which a parastic species has evolved a life history strategy that allows it to use another species to rear its young. It's a great idea (biologically speaking) if you can get away with it. Here, a brood parasitic catfish that utilizes mouth brooding cichlids in the Great Lakes of the African Rift Valley...

If you're a bird watcher, you're probably struck by the similarities between the strategy employed here and those of the brown-headed cowbird (very abundant locally right now). Cowbirds lay their eggs in the nests of a wide range of other species. The eggs hatch early, the nestlings grow fast, and often wind up pushing other eggs and nestlings out of the nest. Here's some video of a cowbird laying an egg in an cardinal nest.

For your viewing pleasure...

Epibulus insidiator, the slingjaw wrasse.

and on a similar note...

Follow the breakup of Gondwana, if you can get past the awful audio (albeit, with a very pleasant Kiwi narrator)..



The movement of continental plates led to the formation of the great southern continent we call Gondwana about 200 million years ago, and began to split it apart some 30 million years later. Among the products of the breakup were the southern continents of of Antarctica, Australia, South American, and Africa - and the islands that today make up New Zealand. By more recent times, the formerly continuous land mass was a fragmented puzzle separated by vast expanses of the southern ocean. Biogeographic questions abound, including the degree to which the current flora and fauna of these derive from a Gondwanan heritage or a later dispersal to their current locations.

A new paper in the American Journal of Botany provides evidence that,for some plants at least, addresses this issue for certain components of the flora of New Zealand. Researchers led by Gregory Jordan of the University of Tasmania report on two new fossils from the heath family (Family Ericaceae) discovered in New Zealand deposits dated to the Late Oligocene/Early Miocene. That puts them between 15 million and 28 million years old. They seem to be of a different lineage than much older fossil pollen finds from New Zealand which go back to the Late Cretaceous, over 67 million years of age. The analysis of the fossils suggests that the ancient pollens represent ericacid lineages that went extinct, with the living heaths of the islands being descended from a much more recent line.

Score one for the dispersalists.

They may like to move it...

...but the question is, how? Some biogeography news that might shed some light on the whole Madagascar-moving issue.

The island subcontinent, which has had some pretty good PR recently, is the proud owner of one of the most unique faunas on the planet. In fact, the world's fifth-largest island, which lies just 300 miles of the coast of southeast Africa, has more endemic animals than any other location with the exception of the much larger island continent of Australia. The most famous of the island's inhabitants are the high profile, photogenic lemurs, but almost 90% of the other amphibians, reptiles, and mammals are found nowhere else.

The animals of Madagascar had to come from somewhere. The island has been isolated for over 100 million years - vertebrate life has been there for less than 65 million. Historically, two competing ideas have suggested different mechanisms for the intial inoculation of the island's fauna - a land bridge which would allow for overland movement or an overseas "sweepstakes" dispersal explanation which envisions ancestral Madagascarians (my word) rafting their way on floating debris.

Each of the ideas has its problems. There's no geological evidence of a land bridge connection between Madagascar and the African continent, and our knowledge of plate tectonics doesn't allow for a drifting continent connection. Furthermore, a land bridge connection would allow for a fairly nonselective introduction of species to the island - large animals like lions and hippos and giraffes in addition to the smaller ones that form the bulk of Madagascar's fauna. On the other hand, the rafting hypothesis is complicated by the fact that existing ocean currents flow in the wrong direction to faciliate an easy drift across the Mozambique Channel.

In a new paper in Nature, Purdue's Matthew Huber and Jason Ali of the University of Hong Kong report the results of computer simulations indicating that ancient ocean currents would have made the rafting possibility much more likely. Huber's simulations, performed on a supercomputer at Purdue and employing information about climate patterns 20 million to 60 million years ago, indicate that currents at the time likely flowed east - toward Madagascar from Africa. Furthermore, they would have likely been strong, fast currents, enabling a small reptile or mammal swept to sea on a raft of floating vegetation to make the shores of Madagascar without starving or dying of thirst.

In biogeography, distribution explanations employing this type of sweepstakes dispersal are sometimes met with skepticism. They are, after all, sort of a wild card. Can't explain a distribution pattern any other way? Then they must have floated there. Modeling techniques such as these may make it easier for us to provide some supporting evidence.

Most remote...

Twelve humans have walked on the surface of the moon. Two have been to the Challenger Deep of the Marianas trench. Fifty years ago. But, marine biologists are focusing once again on this deepest point in the world ocean to learn how life can cope with one of most extreme environments imaginable.

Try this

Mud-ring feeding by bottlenose dolphins...

Brothers in arms...

Malaria is one of the most deadly infectious diseases that mankind has ever had to confront, rivaled only by the bubonic plague which swept through Eurasia in the 14th Century and the smallpox epidemic donated by westerners to the New World. Roughly a half billion people fight the disease annually, with some two million losing the battle. Most of the fatalities are young children in sub-Saharan Africa.

Malaria is caused by a group of protozoans in the genus Plasmodium, the most deadly of which, P. falciparum, is the agent of almost all lethal infections. The parasite is carried from host to host by the bite of the female Anopholes mosquito. Within the human host, the parasites reproduce within red blood cells. The infected experience fever, pain, and weakness. The most unfortunate - coma and death.

A new study led by researchers in France and Gabon has identified another host for P. falciparum - gorillas. The research also provides additional evidence that this deadliest form of the parasite had its origins in another Plasmodium species found in chimpanzees. These conclusions are drawn from fecal samples taken from 125 chimpanzees and 84 gorillas in Cameroon. In the gorillas, the researchers found two new Plasmodium species - and P. falciparum.

The bad news here is that increased contact between the apes and humans resulting from deforestation could lead to increased malarial transmission rates. Another cross to bear, as well, for already dwindling gorilla populations. The "good news", at least on the human side of the equation, is that this adds to our knowledge about the parasite and also about the potential for interspecific transmission of infectious diseases.

And again...

If the last couple of weeks have taught us nothing else, it's that there are far too many causes out there in need of assistance from good people. I won't pretend that the Floreana mockingbird is more deserving than the Haitian people. But the day may come when you have a few extra dollars and there's not a human disaster staring at you nightly from your TV screen. If that happens, the birds that actually influenced Darwin more than those finches deserve a look. Without help, they're probably on the way out.

Nocturnal reading...

A while back, a friend gave me a copy of Pavlov's Trout, by Paul Quinnett. Autographed, actually - Thanks, K. Quinnett's a psychologist, and he writes about the psychology of fishing. It goes a little beyond that, though. One quote in particularly stuck with me...

"Not getting answers to 'Why' leads kids to stop asking, and contributes to the death of their curiosity and hope, perhaps even condemning them to a life of boredom and watching daytime television. Fishermen who keep coming up with one more why question become fish biologists, or ichthyologists, or ecologists..."

True that. Looking for the why.