Saturday, November 28, 2009

Killer Pig

When my 7 year old daughter starts telling me about entelodont biology based on her watching "Prehistoric Predators - Killer Pig" (a National Geographic special), it's kinda cool. When my students start doing it, it's kinda worrying. Dudes - turn off the TV and go read some of those journal articles I gave you! Sheesh.

Friday, November 27, 2009

Revenge of the Phantom Monkeys

Over the last week or so, there has been much chuntering (or perhaps chuckling) on the VP listserve regarding a paper by Michael Heads that was published in the latest edition of Zoologica Scripta. Entitled "Evolution and biogeography of primates: a new model based on molecular phylogenetics, vicariance and plate tectonics," Heads' paper makes the remarkable claim that primates originated in the Early Jurassic, 185 MYA. That's a mere 130 MYA before the appearance of the first primates in the fossil record. Heads further concludes that the split between strepsirrhine primates (lemurs, galagos, lorises and - of course - our old friend Darwinius maxillae) and haplorhines (monkeys and apes, including us) occurred 180 MYA, that Lemurs arrived in Madagascar 160 MYA, and that New World and Old World monkeys diverged 135 MYA. What is particularly awesome about this paper is that there is no evidence whatsoever for any of this, and yet he still managed to get it published.

This isn't to say that his argument isn't worthy of consideration. It draws on two thorny problems for evolutionary biologists. This first of these is answering the question of how modern groups of animals and plants ended up with the global distribution that they have today. Back in the days before plate tectonics, biologists used to postulate the existence of vanished "land bridges" connecting continents or seemingly unlikely models of colonization such as "rafting" (animals get swept out to sea on logs or other floating debris and get washed up in novel places). Then in 1915 German geophysicist Alfred Wegener proposed that the continents themselves might drift around the surface of the planet carrying animals and plants with them and after everyone had finished laughing at him (which took around 40 years) they came to realize that this was actually true. Of course, Wegener had been dead for over 20 years at this point, having expired from a heart attack on top of a glacier in Greenland, so I guess some people may have felt a bit bad about this. But hey, that's science!

The problem is that continental drift can't account for all animal distributions. When you reconstruct the positions of the continents at critical periods in evolutionary history, it becomes apparent that sometimes animals had to cross water to get to colonize new areas. What it can do is make the gaps between continents narrower than they are today, or create island chains through volcanic and other tectonic processes, which then allow species to "hop" from island to island like stepping stones. But even so, you are still left with models that require animals to either swim or float for quite long distances and for some people that's just too unlikely to swallow.

In the case of the primates there are two major instances where this has to be invoked as a scenario to explain modern distributions - first, the colonization of Madagascar by the ancestors of today's lemurs, which are believed to have arrived from Africa somewhere between 50 and 80 MYA, and second the origins of South American monkeys, which are also thought to have evolved from African ancestors around 35 MYA. In each case, the conventional model of biogeography says that they did this by rafting across the Mozambique Channel and the Atlantic respectively, both of which were narrower at the time when these events occurred.

Phooey - or words to that effect - says Heads. The most parsimonious solution to this problem, given that Africa was at one time connected to both South America and Madagascar, is that the ancestors of these groups were once part of a widely distributed population of proto-primates that fragmented as the continents broke apart. That being the case, you can date the origins of each group of primates, plus some of their close relatives, to the radiometrically determined dates for the separation of the continents. Which all occurred during the Jurassic.

There are certainly animals that look like mammals around in the Jurassic, but none of them are particularly like the modern-day groups and many palaeontologists prefer to call them "mammaliaformes" to differentiate them from the "crown group Mammalia" as the true mammals are known. There's certainly nothing remotely resembling a primate; the earliest known eutherian mammal, Eomania, is 125 million years old. That makes it about the same age as the earliest known ancestor of marsupials, Sinodelphys, and 2 million years older than the oldest monotreme, Teinolophos.

This brings us to the second thorny problem, which is what to do about dating evolutionary events that must have happened (e.g. the origin of primates) but for which we have no direct fossil evidence. Finding the oldest fossils in different lineages is helpful because it enables us to fix the latest date for the common ancestor of those groups. So if Eomania and Sinodelphys are both 125 million years old, and Teinolophus is 123 million years old, then the common ancestor of modern mammals (monotremes + marsupials + eutherians, incl. primates) cannot be less than 125 million years old. The problem is that we can only use the fossil record to fix the most recent date. Absence of evidence, as we all know, is not evidence of absence and given the notoriously patchy nature of the fossil record there may be earlier members of these groups that are as yet undiscovered.

As ever, molecular biologists think they have an answer to this. Back in the 1960s (which is like the stone age of molecular studies) they made the observation that the molecular sequence of a variety of biological molecules, including proteins and DNA, changes over time. It follows, they hypothesized, that the magnitude of the difference between the same molecule in two different groups of organisms is a reflection of the time since the two lineages diverged. Provided that this rate remains constant, you can calibrate your "molecular clock" to figure out how long ago the common ancestor of the two groups. Once again hard science triumphs over the woolly uncertainties of the fossil record. Hurrah!

Of course, it's not as simple as that because the clock does not "tick" at the same speed in different lineages. Albatrosses have molecular clocks that run at half the speed of other birds. Small mammals accumulate molecular changes at 8 times the speed of turtles. Over time and much study it's become apparent that there are several factors affecting the rate of molecular change, including population size, the time taken to reach reproductive maturity, the intensity of natural selection, and physiological differences between species. This means that you have to apply a series of statistical and computation fudge factors to your analysis to compensate for these confounding variables. In short, the molecular clock can provide supporting evidence for a hypothesis, but is not direct evidence. This is a pity for Heads, because the molecular clock for primates does suggest an earlier origin for primates than the fossil record - but only 80-116 MYA, which is still a good way short of his 180 MYA model. Having said so, there's no more evidence for 80 million year old primates than for 180 million year old ones.

Heads' Jurassic primates are a classic example of a "ghost lineage." Ghost lineages are phylogenetic branches that are inferred to exist, but for which there is no direct (i.e. fossil) evidence. Ghost lineages are a plague for those researchers interested in the early history of the modern placental mammal groups because molecular dating suggests that they originated back in the Cretaceous, but so far no-one has found a fossil member of one of these groups that predates the K/T boundary 65 MYA. Open-minded paleontologists (and there are a few of these rare creatures around) are prepared to at least consider the possibility that there might be some late Cretaceous primates kicking around. But no-one is going to swallow the idea of an unrecorded evolutionary history for primates that is almost three times longer than their known fossil record.

Why? Well, the fossil record for Mesozoic mammals isn't great, but it's still good and we know from the fossils that there were other other animals of similar size and ecologies (e.g non-placental eutherians) known from the "missing" time period. That means that you have to start coming up with increasinglt tenuous arguments to explain why the animals in question (e.g., Jurassic primates) are completely missing. Plus, if you accept that there were primates in the Jurassic, then you also have to conclude that the diversification of almost all the groups of placental mammals took place even earlier than this. Not being able to find a fossil of a Jurassic primate is bad enough; not finding evidence of *any* modern group if their ancestors were all present makes this hypothesis untenable.

Tuesday, November 24, 2009

More Like What We Were

Many thanks to my colleague, James Bryant, who posted a link on NHCOLL-L to this splendidly Pooterish article in the Chronicle of Higher Education. The author is one Thomas H. Benton; "Thomas H. Benton," apparently, is the pen name of one William Pannapacker, an associate professor of English at Hope College MI. (As an aside, I don't get why you would write an article under a pen name, then tell your readers your real name. Doesn't that defeat the point? Or is it like me saying, "hi, this is Chris, but today I'm writing in my Chuck persona?") Benton/Pannapacker's thesis is that some time in the past natural history museums lost their way - reading between the lines, this seems to have a lot to do with letting children in to run around the place with a lack of "decorum;" as with most things that are bad for you, this began in the 1960s. Damn those Baby Boomers!

I'm being a little unfair, because it's a better article than that. After starting unpromisingly with one of those thumbnail sketches of "man in a cluttered office full of interesting things" that serves as the lazy writer's shorthand for the eccentricities of museum life, Benton goes on to explain that such places as this office "are the accidental accumulations of time, rather than the clean, uniform, and often deadening spaces created by committees governed by the orthodoxies of a narrowly defined mission." Crikey, you can tell he works in the humanities, can't you? I feel obliged to note that they are also places where irreplaceable specimens get lost for generations, armies of cockroaches breed, and fires start in trashcans.

After this, we meander through some warm fuzzy reminiscences of Benton's youthful dalliances in various natural history museums, before finally getting to the meat of his argument. "At some point, apparently back in the 60s, natural-history museums began to focus on attracting children; it made sense for demographic reasons allied to the educational imperatives of the Cold War." Silly me - there was I, thinking that we wanted to use natural history to inspire and awaken their interest in science. Now I realize that we were just slaves to our educational imperatives. Anyway, it seems that grown-ups don't come and visit our museums any more. "Could you imagine a sharply dressed couple walking through a natural-history museum, making sophisticated remarks about the archaeology of knowledge and the frisson of old and new epistemologies?" ponders Benton. I am not ashamed to admit that I wept openly at his vision of what we have lost.

Anyway, the good thing about this article is that Benton does actually make some concrete suggestions about what natural museums should be doing about this. I'm not going to go through these point by point; you can go read them yourself. Some are reasonable; some describe things that museums are already doing; some are provocative; and some are just plain daft ("teach the conflicts"? - oh please, Thomas, you sound like a warm-up act for Kirk Cameron). So I'll just pick a couple of his ideas that I think are worth looking at in more detail.

First, Benton thinks museums should "stop being ashamed of dead animals." What is it with these social historian types? They're obsessed with taxidermy - my wife and I used to joke that the only time that natural history museums turned up in Museums Journal was when someone (and it was never a natural history curator) tried to turn taxidermied specimens into the front line of the culture wars. This happened every couple of years, regular as clockwork. I'd hate to break it to these guys, but the main reason museums take taxidermy off display is that it's really, really bad taxidermy - for every masterpiece like a Carl Akeley or Perry Wilson diorama, there are a hundred sausage-shaped monstrosities with bulging glass eyes and straw sprouting from their seams.

Second, Benton is not a fan of anthropology in natural history museums. "Apart from prehistoric human evolution—a branch of the history of primates—avoid anthropology, which has often led to ill-considered displays of indigenous cultures that are offensive and rightly scare away potential supporters." He's not the first to make this point and there is a case to be made that it is intrinsically offensive to display non-western cultural objects alongside animals in a natural history museum, rather than in a museum of art or ethnography.

The counter argument, of course, is that museum displays exist to share the museum's collections with the widest possible audience (or at least, they should do) and that, like it or not, many natural history museums have extensive and important collections of human artifacts. You could also argue that humans are part of the natural world and that our culture is an integral part of the biology of our species.

Then there is the historical angle. Elsewhere in his article, Benton argues forcefully that museums should not "sacrifice" their history and, like it or not, museums have an unenviable history as promoters of scientific racism in the 19th and 20th Centuries. If you want to read more about this, I'd suggest taking a look at "The Race Gallery" (1995), Marek Kohn's masterly overview of racial science. Forget futile attempts to engage with the creationists - here indeed is a "conflict" worth teaching.

Sunday, November 22, 2009

Samson - An Update

Back in September, I posted on the forthcoming auction of a substantially complete skeleton of Tyrannosaurus, called Samson, that was about to go under than hammer at a Bonham's auction in Las Vegas. For those of you who still don't know, it failed to reach its reserve price of $6 million; the highest bid was $3.7 m. The owner initially declined to part with Samson for less than the reserve, but on November 12 of this month Bonhams announced that a sale had been made. As ever, the buyer remains anonymous. Various news outlets trumpted this story as "Sampson is Heading for Museum," or headlines to that effect. This is not entirely true.

What's actually happened is that the new owner is trying to find a museum that is prepared to take Sampson on loan for the purposes of display. Now you might think that any self-respecting museum would jump at this opportunity but, as ever, it's not as simple as that. Sampson will take up a sizeable chunk of display space; will probably require the museum to shell out significantly to develop lighting and display content; and will require hefty insurance cover. And all of this assumes that the new owner will not be charging for the loan. It's far from clear that this will be the case - Bonham's auction catalog was quick to highlight the moneymaking opportunities presented by owning your own T. rex.

All of which means that if it were my museum that was interested in taking Sampson, I'd have lawyers crawling all over the loan agreement. I'd want a long loan period - maybe as much as 10 years - with first refusal on a renewal. I'd push hard for a cast specimen (at a discounted price), to permanently replace Sampson at the end of the loan. I'd want far-reaching waivers of liability for any damage incurred while on display and I'd probably insist on the donor handling care and maintenance, even if I had in-house expertise. I'd also be considering doing a deal to license any exhibit content I develop, for use with casts of Sampson that the owner is selling or loaning to other museums. And I'd want to be able to make the specimen available to visiting researchers as well as the general public; this would be subject to formal approval by the owner, but I'd want a "which will not normally be refused" clause. Actually, I probably want a lot more than this, which is why I raised a skeptical eyebrow when Bonham's spokesman said the new owner was planning on having it on display by Christmas. It may well be on display, but I doubt whether this will be in a museum.

So, is this a bad thing? I guess the answer is "not entirely." Sampson will be on exhibit, which is good. A canny museum, with good negotiators that can develop a partnership with the owner, could actually come out of this with a pretty sweet deal. And while this might be a novel situation for natural history museums, our colleagues in the art world would barely raise an eyebrow at the idea of borrowing a privately owned work for exhibit. Sampson is a bit more complicated than this, because there's more involved than just hanging a painting on a wall, but the general principles are the same. In an age when private ownership of fossils has become rather fashionable, we may have to swallow hard and get used to arrangements like this.

The downside, of course, is the issue of permanence. Another fact that emerged in the post-sale interviews is that the new owner is the third one that Sampson has had since it was discovered. If the skeleton remains in private ownership, it can be sold again and again; in these days of financial upheaval, that's a very real possibility. Which means that for all the good intentions of the current owner there's no certainty of access in the long-term, either for the public or for anyone wanting to carry out research on this specimen. As I've said many times before in this blog, this is why you put things in museums - so that future generations have a guarantee of access. This is why our community gets upset when universities like Brandeis start talking about selling off their collections and why I get twitchy when museum policy wonks get all gung-ho about deaccessioning.

So if you happen to be the mysterious new owner of Sampson, congratulations on your purchase and much kudos to you for moving quickly to get it onto public display. I urge you to put it in a museum (rather than a casino lobby, for example) and to partner with that museum to produce some really high-quality educational and exhibit material to make the best possible use of an extraordinary specimen. But beyond that, you should think seriously about donating the specimen. Yes, it's cool owning a T rex, and it did cost you a ton of money. But anonymous or not, donating it would put you into the big league of museum philanthropy, and earn you the gratitude of an army of future museum goers.

Friday, November 20, 2009

Deaccessioning. Again

Flipping through the pages of Time recently (hey, I don't have time to analyse the news myself. I need someone to do it for me. Preferably with nice graphics and a couple of bar charts) I came across this article, which is yet another "hey, why don't we make deaccessioning sexy by asking the public what they think we should throw away. This time it's UCL. Guys! This is like so five minutes ago. Manchester did it far better with the hermit. At least UCL didn't clutter up their rationale with a bunch of guff about how this is making their institution sustainable - they cheerfully admitted that their major aim was to make space for new stuff. I'm all in favor of collecting; collect-or-die is an excellent motto for museums. Except natural history collections where it's more a case of collect-and-die, especially if you happen to be the unfortunate organism being collected.

The Time article implies that the UCL exercise and ones like it are shining a light on the processes by which museums dispose of material and that this is something that many museums would like to keep hidden because it is contentious; they cite the recent Brandeis case as an example of the passions that might arise. Personally I think this link is a bit tenuous. In 20 odd years of working with collections, I have never disposed of anything where I wasn't 100% sure it was a piece of worthless junk; if I was less sure than this, I kept it. There's nothing at all contentious about that. What aroused fury about Brandeis was not disposal per se (although there were plenty of people unhappy about that as well) but the fact that the university was proposing to sell off the collections and use the proceeds to fund other, non-museum activities. This is generally considered to be a breach of the institution's duty of reasonable stewardship. Now, an article where museums talk candidly about responsibility - that would be worth reading.

Saturday, November 14, 2009

2012

If you've been living under a rock (or perhaps in Utah) for the past few months, you may have missed the fact that a movie called "2012" is opening next week. For the rest of you, I'm sure by now you are heartily fed-up of the barrage of Mayan-inspired pseudoscience whirling around this movie, which posits that the world will suffer a series of planet-shaking catastrophies in a couple of years' time. No? Well, here's some more.

2012 is the brainchild of German director Roland Emmerich. Emmerich is a cinematic bĂȘte noire of mine, rivalling that other dollar-guzzling monster Richard Curtis. While Curtis's speciality is cheerily heartwarming tales of middle-class British niceness masquerading as comedy, Emmerich specializes in heartwarming tales of ordinary folk surrounded by the deaths of millions. He has become known as a specialist in end-of-the-world disaster movies, whether through alien invasion ("Independence Day"), climate change ("The Day After Tomorrow"), or giant radioactive lizard ("Godzilla")

My grudge against Emmerich goes back to his Revolutionary War epic "The Patriot" (2000). I could forgive him casting an Australian (Mel Gibson) as the only non slave-owning Southern landowner in the 18th Century, or for having another character who was a heroic Frenchman (obviously a foretaste of Emmerich's later science fiction and fantasy films). No, what I objected to was having him turn my fellow countrymen into a bunch of barn-buring Nazis. Sorry, Roland, but it was your army that did things like that, not mine.

However, like Curtis, Emmerich seems to be a nice man, who has been an active campaigner for gay rights; against racism in Hollywood; and promoting awareness of global warming. And it's not really his fault if there are a bunch of wingnuts out there that think his film is true. He has managed to skillfully weave a bunch of genuine geophysical nasties like the Yellowstone Supervolcano, Mega-tsunamis, and "The Big One" into a tale of planet-crushing horror - all that's missing from the mix is a dose of Asteroid Porn. Setting aside the morality of treating the deaths of millions as suitable subject for entertainment (hey, if you don't want to watch, you don't have to go) and Emmerich's formulaic "ordinary-joe-thrown-into-desperate-struggle-for survival" screenplay, it's probably not a bad date movie.

However, it has given a raft of academics from a variety of fields the opportunity to get onto TV (and into the papers, and on-line) and, in doing so, get some real research into the spotlight. How long has Mayan cosmology been waiting for it's day in the sun? But if there's an astronomical phenomenon that needs explaining, my go-to guy is the awesome Neil DeGrasse Tyson, Nova presenter and Director of the Hayden Planetarium at AMNH. Sure enough, last week Tyson sent all staff at AMNH an email circular that pulled no punches:

Now occupying nearly 50-million web pages on the Internet, the 2012 fears derive from nothing more than a hoax of the scientifically illiterate perpetrated on the scientifically uninformed.

Wow - I'm totally going to steal that line and use it at dinner parties. If you change the "2012" to, say, "H1N1 vaccine," "Darwinius maxillae," or "the millennium bug" you'll see that it has broad applicability for a variety of scientific debates. Of course, Tyson then went on to undermine the considerable force of his argument (IMO at least) by giving readers three video links to calm their fears; CNN, Jimmy Fallon, and a video Q&A. All featuring.... Neil DeGrasse Tyson. Some people may fear the impact of a planet-sized body on Manhattan, but as far as I can see a planet-sized ego impacted there some years ago with minimal damage and is still around today.

[disclaimer: after I pointed out Tyson's self-promotional chutzpah to a colleague of mine, I was accused of being a "hater." So, for the record, I think Neil is one of the best popularizers and advocates for science around today. And I am not a "hater." Except where Richard Curtis is concerned]

Stuck in Perissodactyl Hell

I've not been very productive on the blog front this month, partly because I'm mired in a project to develop a website on perissodactyl evolution. This is something that I should have kissed goodbye to when I left AMNH, but like Brer Rabbit's tar baby, it seems to have come along for the ride to Yale. Between editing the reams of text generated by our consultant; trying to find decent, copyright free images of obscure Eocene perissodactyls (Palaeotherium, anyone?); and manually inserting creative commons links for said images, I've been run ragged.

Then there's the etymological glossary of names of perissodactyls and other fossil mammals mentioned in the site. Why did we ever decide to do this? One of the problems with early authors of names (e.g. Cope and Marsh) is they assumed that their readers would have had the benefit of a classical education and that providing an etymology was a redundant exercise.

Thank God for Theodore Sherman Palmer, who in 1904 published the Index Generum Mammalium, 984 pages giving the authors, citations, and etymology of every genus of living and fossil mammal known at that time. And thank Google for scanning the whole thing and putting it on line - you can view it and download a PDF copy here. Of course, those pesky Greek roots are all in the Greek alphabet (even Palmer wasn't above making assumptions about his reader's education), but armed with MS Word's Greek typeface and the awesome Greeklish Converter even this problem is not insurmountable. God, I love the web.

Anyhoo, I'm on track to deliver the site content to my colleagues at AMNH next week. This is about the time that the content for the Paleoportal Fossil Preparation website should arrive from my other consultant. Which also needs editing for a deadline. Then in the monthly collection managers meeting, I get told that I'm being volunteered to review collections content for the Peabody website.

God, I hate the web. I'm going to unplug my computer and go back to writing letters. With a quill pen.

Tuesday, November 10, 2009

One word - plastics

A friend of mine, Terri, sent me a link to this website. It's one of those sites where you don't know whether to laugh or cry. On the one hand, it looks like some bizarre art school project. And on the other hand it's a tragic indictment of just how polluted our oceans are becoming. These photos are the remains of Laysan albatrosses (Phoebastria immutabilis), which nest on Midway Atoll in the North Pacific. Ocean currents in the Pacific cause floating plastic garbage to accumulate in two huge patches, which happen to be right within the feeding grounds of the albatross - you can read a paper on this that was published by Young et al in PLoS ONE by clicking here). The adult albatrosses are attracted to the brightly colored plastic, swallow it (hey, they're birds - noone claiming they can make good choices), then fly back to Midway to feed it to their chicks. The website, which was produced by photographer Chris Jordan, shows what happens to the chicks - they fill up with inedible plastic doohickeys and eventually die. On the plus side, the Laysan albatross is the second most common seabird in the Hawaiian Islands, with a population of 2.5 million birds and a range that is expanding to include new nesting islands. Having said that, they're going to need to breed at a furious rate to offset this mortality.