Saturday, January 29, 2011

"On the Origin of Feces," or Do Scientists Have a (Sick) Sense of Humor?

Charles Darwin Biography

Well, judging from the last post, I suppose the answer to this question is probably moot (at least the "sick" part).  But I hope you'll indulge me nonetheless for another brief probe into the murky depths of scientific so-called humor, using the sordid story of my own personal (d)evolution as a guiding thread before I move on to other topics in later posts.



Scientists have a reputation among the general public for being strictly rational, fact-obsessed, and devoid of feeling (apart from the "mad" varieties who cackle gleefully as they plan to destroy the world, etc.).  But if you hang out with enough of them for long enough, you'll find quite a bit of humor bubbling up here and there like unexpected springs in a desert. Much of it, of course, is distinctly nerdy in flavor, often salty as well,  and even more often eccentric enough to reinforce the "mad" characterization of our kind.

One of the classic figures in this regard is satirical musician/science-math guy Tom Lehrer.  Perhaps my favorite piece of his is "The Elements," a fast-paced run-down of the first 102 elements on the periodic table set to a Gilbert and Sullivan melody. (listen here, if you dare: http://www.archive.org/details/elements_0).



I would KILL to be able to perform this myself, but even after listening to Lehrer's recordings for the last 4 decades I still can't fully wrap my brain around it.  Even so, I suppose I can attribute at least some of my own twisted psyche to having imprinted on this crazed genius at an early age.

During my college years at Bowdoin, my fellow students and I were occasionally stunned to realize that our science profs were at least semi-human enough to attempt humor in front of the class.  My anatomy professor, the late Jim Moulton, once shocked us by bursting into song as a way of illustrating the history of vertebrate evolution, singing about Amphioxus (a primitive marine vertebrate, pictured here) to the tune of "It's a Long Way To Tipperary:"



"It's a long way from Amphioxus. It's a long way to us.
It's a long way from Amphioxus to the meanest human cuss.
Well, it's goodbye to fins and gill slits, and it's welcome lungs and hair!
It's a long, long way from Amphioxus, but we all came from there."


(a YouTube version here: http://www.youtube.com/watch?v=LNoHBU1He1o  )

Geology professor Art Hussey used to spice up his lectures by punning on geological terms ("Don't take it for granite.") and occasionally delving into the raunchy side (typically in reference to minerals with such choice names as "virginite," pictured here).



One of our favorite geo-tales from "Huss" was about two paleontologists who lost their long-standing friendship when one of them named a newly discovered fossil creature after his buddy-colleague.  The tiny marine snail was found attached to a fossil crinoid (a kind of stalked starfish), and it later transpired that such snails are indeed typically found with crinoids, usually attached to... the place where, um, waste is excreted.  One can quickly deduce what the snail's diet probably was.  Sadly, the fellow for whom the poop-eating snail was named refused to believe that his former friend hadn't done it on purpose, and never forgave him for it.

As a graduate teaching assistant at Duke, I watched master teacher and biomechanics guru Steve Vogel use vivid imagery to get otherwise abstract scientific points across to his undergrad non-major science classes.



One particularly memorable explanation had to do with "positive feedback loops," in which a process makes itself more and more extreme the longer it continues (a key concept in biology and also in climate change; for example, warming thaws permafrost which releases more methane which causes more warming, etc.).  I'll paraphrase him here.

"Imagine you're in bed, naked, with the partner of your dreams," he'd say.  Nodding heads invariably jerked to attention at that. "The room is chilly, but you've both got an electric blanket over you.  However, in the distractions of the moment, you didn't notice that the control mechanisms for your individual blankets have been switched."

 

More giggles.  "As you feel the chill, you turn up the thermostat on your blanket.  But all that does is warm your partner up, thanks to the switch.  They feel too warm and turn their own thermostat down, which makes you feel even colder.  Pretty soon, you're freezing while your partner is roasting.  That, my friends, is how a positive feedback loop works."

While on a 3-month expedition through the South Pacific Islands in 1983, botanist John Kress used to lighten our mood by making jokes about potholes in the local tarmac that made travel a trial.  "Those are dug by the Excavatia bird," he'd say. "It digs those holes in hopes of causing an accident so it can feed on unlucky tourists." 



When swerving to avoid said potholes caused an overhanging arm to rip through the pricker bushes lining the  road, he'd say "Ah, that was another species, 'Excavatia talon.' It places the potholes in such a way as to divert cars close to the vegetation where it lurks, ready to reach out and snag pieces of arm with its claws."

And whenever I'm feeling queasy at sea, I think of my friend and fellow Dukie, oceanographer Larry "Caboom" Cahoon, who used gallows humor on any students foolish enough to show up late and hung-over for one of our early-morning sampling cruises along the Carolina coast.  As soon as the breeze picked up and the sea started turning rough, he'd sidle up close to the greenest-looking miscreant and hold forth. 



"So, listen up," he'd say to all within earshot.  "Here's today's physiology lecture. There are three stages of seasickness. Stage one is when you're afraid you're going to die.  That's apparently where some of you are at right about now.  But don't worry, losing a few cookies is no big deal." 

By that, he meant that things were only going to get worse from there on out, as he'd then proceed to explain in his usual deadpan fashion.

"Before too long, you'll probably move on to stage two, which is when you KNOW you're going to die.  But that's nothing.  Just wait until you finally reach stage three, which is when you're going to WANT to die!"

With all this exposure to the twisted side of science, I suppose it's no surprise that I've been terminally affected by it.  During grad school, though, it led me to the greatest  heights (or depths) when my pal/colleague Kurt Haberyan published a paper describing what appeared to be the fossilized dropping of  copepods (tiny, shrimp-like plankton animals) in a billion-year-old rock deposit. He and his advisor got the discovery into print in a major journal because it seemed to represent some of the earliest signs of animal life ever found.



Some reviewers, however, were skeptical because nobody had ever found fossils of copepods themselves from rocks of that age.  "He must have misidentified the pellets," they claimed, "because copepods hadn't evolved yet."



In a flash of inspiration, I experienced my first "eureka moment" as a budding scientist. The skeptics had completely missed the most important aspect of Haberyan's discovery. By finding copepod pellets that pre-dated the origin of copepods, my friend had demonstrated something that would revolutionize evolutionary biology.

Scribbling feverishly, I penned what would later become a short article in the Journal of Irreproducible Results (the very existence of which was a testament to the secret depravity of scientists), under the title "The Origin of Feces."  Its thesis (no almost-pun intended) was that the evidence should be taken at face value; clearly, feces evolved before animals did.




It made sense then and, to my continuing horror, it still does. See if you can disprove it.  If you can, I'll eat a copepod pellet.

Here are the basics.  Feces evolved in the organic, bacteria-rich, primordial ooze at the bottom of the sea; that's why they look and smell as they do.  Animal bodies evolved later as shelters, means of transport, and nutrition-collecting mechanisms that pass resources down into the intestinal breeding grounds from which fecal progeny continually emerge.  Sewer systems which eventually drain into the oceans are actually migration routes along which young feces seek to return to their ancestral home.  Genes are merely the blueprints with which feces construct more host-bodies for themselves.  The primacy of feces over bodies is perhaps most clearly illustrated when an animal is in deadly, terrifying danger.  At such times, notice what often happens at the rear end of the animal, as the small, brown residents slip quickly and quietly out in an effort to escape...

OK, I know it's over the edge, and what little reputation as a serious scientist that I may have had before has surely been demolished now by this posting.  Just remember that I was merely a young, naive grad student at the time, not the all-knowing paragon of professional respectability that I am today.

But there's another reason why I'm confessing this Origin of Feces thing to you-all here.  I think it's a potentially useful teaching tool, not unlike the Flying Spaghetti Monster (Bless His noodly appendages, and learn more about Him at http://www.venganza.org/ ).  I sometimes use both of them in my classes now that I'm all grown up and can inflict sick science-humor on my own crops of hapless college students.



Like the "F.S.M.," my older but far less famous "O.O.F." hypothesis illustrates an important concept, that just because an idea fits a given array of facts doesn't necessarily mean that it's correct.  That's the problem with most arguments in support of so-called "intelligent design" or climate denial, in which an incomplete set of data is presented and may even seem to make some sense when strung together in a certain way.  But it doesn't really prove the point that the creationist/denier is trying to make.

It's also a reminder to scientists and their supporters that seemingly loony ideas are not always totally irrational or baseless, and that a single array of reputable facts may sometimes yield different yet more or less reasonable interpretations among people who have different worldviews.

So don't worry.  I don't really believe in the FSM, and most certainly not in The Origin of Feces.

No, really.

I mean, it simply can't be true because... um, well, because...

Hmmmm.

Saturday, January 15, 2011

"Always look on the BRIGHT side of... global warming."



The ironic closing song from the Monty Python movie, Life of Brian ("Always Look On the Bright Side of Life"), came to mind after a friend passed this news along.  According to a story in the Daily Mail, dawn came two days early to a coastal settlement in Greenland this winter.

http://www.dailymail.co.uk/sciencetech/article-1346936/The-sun-rises-days-early-Greenland-sparking-fears-climate-change-accelerating.html#ixzz1B1XeKod5

Because of the high latitude there, the sun doesn't rise over the horizon in mid-winter, causing a weeks-long "midday moon/gloom" as opposed to a "midnight sun" in summer.  Normally, the residents of Ilulissat watch it re-appear over the eastern horizon on January 13.  But, according to the Daily Mail, the sun showed its face two days earlier than expected last week.

Is global warming making days longer?

Low horizon: The fishing town of Ilulissat is Greenland's most westerly habitation. Temperatures in Greenland have risen 3C above average over the last year
Ilulissat, western Greenland.

Well, assuming that the report is accurate (I'll assume here that it is), then the answer is a qualified "yes."  In Ilulissat, anyway.

The best-sounding explanation seems to be related to local geography.  Ilulissat lies on the edge of Greenland between the sea and the western flank of the mile-or-more-thick inland ice sheet.  Because the downward-sloping margins of the gigantic ice slab lie low enough to dip below the freezing point in spring/summer/fall, and because of the ongoing warming trend, it stands to reason that the surface of the ice may have dropped somewhat.  That, in turn, might expose the horizon-hugging sun a bit earlier in January.

Again, I don't know if the story is even true.  The reader-comments below the online story certainly do hurl a torrent of abuse at it, but that's sadly typical of any global warming story these days. 

OK, I admit it.  I WANT it to be true.  Even though it suggests that massive environmental changes are afoot, this story is kind of cool, and it seems too crazy-sounding to be fictional.  And it's nice to think of finding a tiny bright spot in what can otherwise be a dark, depressing topic.

I am therefore not going to dig into it any farther online, for fear of finding out that it's a bunch of hooey. Instead, I'm going to take off my "dispassionate scientist cap" now and just run with the idea. 

First thought to play with: how could such a big change happen so suddenly?  The article makes it sound like it all happened within the past year.

Maybe there's a reasonable-sounding mechanism by which such a rapid change could occur.  Greenland's largest outlet glacier, the Jakobshavn Ice Stream, lies nearby.  It's always been a major source of icebergs, and probably spawned the one that sank the Titanic.  Maybe some surge in that outlet has drained enough ice to drop the surface noticeably where the sun normally appears on that particular skyline?


Jakobshavn ice stream draining the main ice sheet, with a conveyor belt of icebergs flowing from right to left.  The edge of the solid stuff at the head of the ice stream has retreated inland over the years.

So with that hypothetical explanation in mind, let's say it's true.  Daylight season is getting longer in Ilulissat, thanks to global warming. And in a warming future, the trend is likely to continue, perhaps until all of the marginal ice is gone.

Now with the aforementioned hypothetical explanation paving the way to more speculation, let's move on to this question...

Isn't that kind of a GOOD thing, in a way?

The more ice that melts, the more sun they get in Ilulissat (and, presumably, all along the eastern and western coastlines).  Longer growing seasons over time could mean more fresh produce on local dinner tables - nowadays, most veggies are imported at great cost, which puts them beyond the reach of many Greenlanders. 



Wouldn't it make for shorter "Seasonal Affective Disorder" seasons, as well?   And cheaper heating and lighting bills?

On the other hand, the longer sunlit season should also add to the local heating trend, I suppose.  More sunlight hitting Greenland's dark, ice-free rind of rock could produce something akin to the urban "heat island" effect that makes cities hotter than they otherwise would be, thanks to heat-absoring roads, roofs, and parking lots.  And if this is true, then maybe it also holds true in Antarctica, which could be scarier.  The unstable ice sheet on the West Antarctic Peninsula is being warmed especially intensely by air and ocean currents, and there's a good chance that much of it could slide off into the ocean as a result.  That would raise global sea levels by several feet over several decades.



If melting has lowered skylines there as well, then maybe locally extended light-seasons could be amplifying ice losses there, too, thereby increasing the risk of a slide-off?   However, there are no "native Antarctican" towns there to have kept track of such things for us, so it's just a guess.

But this is all just speculation, of course.  For all I know, the whole Ilulissat sunrise thing could be fake.  If you find out that it is, DON'T TELL ME.    :)

And besides, we all know that this global warming stuff is just a bunch of propaganda anyway, right?  At least, that's what the critics of the Daily Mail article tell us.  So if global warming has been getting you down, just remember to take Eric Idle's advice - always look on the BRIGHT side of life...



He'll even sing it for you  here, if you like:
http://www.youtube.com/watch?v=1loyjm4SOa0

Always look on the right side of life...
(Come on guys, cheer up!)
Always look on the bright side of life...
(Worse things happen at sea, you know.)
Always look on the bright side of life...
(I mean - what have you got to lose?)
(You know, you come from nothing - you're going back to nothing.
What have you lost? Nothing!)
Always look on the right side of life...

Saturday, January 8, 2011

Where have all the cave-relatives gone?

 Cast of Cavemen TV  show

Most of us think of humans as being exceptional among Earth's organisms because, well, because we're the only ones that are so... human. 

But that's not how it used to be.  And some of this past year's discoveries in the world of paleo-anthropology really drive the point home.

Anatomically modern humans date back roughly 200,000 years, having arisen in Africa from "archaic" types who in turn probably arose from Homo erectus.  Nowadays, we're the only living members of our genus and species, which makes it especially easy to focus on our uniqueness.  Such alone-ness also feeds into mistaken ideas that evolution is a linear process with the singular aim of producing modern humans like ourselves.

But for most of our existence, we had company, and plenty of it.   

Neanderthals split somewhat from our direct lineage about half a million years ago, but they continued to share Europe and the Middle East with our forebears until about 30,000 years ago, and according to DNA analyses published in 2010 by a team headed by Ed Green of UC Santa Cruz, they also shared in more intimate ways.  As this web article explains, they also interbred with our ancestors.  (http://news.nationalgeographic.com/news/2010/05/100506-science-neanderthals-humans-mated-interbred-dna-gene)

A reconstruction of a Neanderthal female.

A Neanderthal-female reconstruction based on both fossil anatomy and DNA. Photograph by Joe McNally, National Geographic.

Strictly speaking, Neanderthals and our direct ancestors were therefore members of a single species, representing two slightly different branches of the same family tree.  In other words, they were "people," too; or maybe "people-cousins" is a better term to use.  Either way, we lost them about 30,000 years ago, for reasons that are as yet unknown.

And then there were the human-like, Neanderthal-like "Denisovans," whose DNA was recently coaxed from a 30-50,000 year old finger bone that was found along with a molar in Denisova cave, southern Siberia.  We don't know much about them yet other than that they (or at least their fingers and molars) lived in southern Asia, and that much of their genetic heritage lives on among Papuans and Aboriginal Australians. ( http://www.scientificamerican.com/article.cfm?id=new-hominin-species )

 

Apparently, the ancestors of today's Melanesians interbred with Denisovan people-cousins in Asia on their way to New Guinea, Australia, and Pacific islands farther eastward.  In other words, the Denisovans were enough like us to bear and/or produce viable human children.  But now they're gone, too.

The following chart suggests that a walk in the woods or steppes of Europe or Asia 40,000 years ago could have been a wildly multicultural experience.  Back then, you could have encountered all sorts of "regular" folks, plus Neanderthals and Denisovans (and, as noted on the chart, the pint-sized Homo floresiensis "hobbits," as well, though we don't have the full genetic scoop on them yet).


 Meet the Denisovans



This is pretty cool stuff, prime material for daydreaming about stone artifacts and bones and digs and Indiana Jones hats.

But when I stop and really think about it, it's more than that. 

Don't simply think of them as having disappeared tens of thousands of years ago, or you'll fall into the usual trap of assuming that they were just half-baked evolutionary dead-ends that are naturally "supposed" to be extinct.  Think instead of the whole half-million-year span of our mutual co-existences, and you'll notice that they lasted quite a long time alongside us and then vanished relatively recently.  If that time period were shrunk down to the span of a single day, our people-cousins would have disappeared just an hour or two ago after spending all day and most of the night with us.

From this paleo perspective, it's rather odd that we're now the only form of humanity on Earth. And that realization makes it easier to take the next step and ask: what would it be like if those people-cousins were still with us today?

Have you seen any of these "Geico cave man" ads (below) on TV or YouTube?   If not, look some of them up on Google and check them out. They're hilarious, but also somehow oddly troubling, as well. Sometimes I think they make us laugh so hard because they also make us uncomfortable.

 Caveman appears on television
The main premise of these skits is that we try hard to avoid being "politically incorrect" when discussing different ethnic groups nowadays, but we still get away with speaking of cave people as dimwitted brutes.  These characters bring cave men into the present day to confront us with those negative stereotypes, and we laugh to hear them chastise us for our modern-human-chauvinist-piggery. 

Entertainment and marketing techniques aside, I think it's a fantastic way to force ourselves to think of these close relatives as being the real people that they actually were. 

We normally tend to think of "cave men" as non-humans, as barbarian "others," as symbols of humankind's basest instincts and behaviors...just as people have so often done to members of other racial/cultural/religious/political groups throughout history.  It happens most often when people don't know each other very well on a personal basis and, of course, it's particularly hard to get to know someone who has been dead for 40,000 years.

But even so, I sometimes wonder what the modern world might be like if, in addition to the many differences that so often seem to divide and trouble us, we also had to deal with the ethics and complexities of interacting with Neanderthals and Denisovans. 

Would they be subject to the same rights and expectations as the rest of us, or would we treat them as we do chimps, which have only now become our closest living relatives?

What would religion be like with people-cousins still among us?  Would some neo-evangelists claim that God actually created the world for Neanderthals to hold dominion over, and then point to the environmental damage that we "regular" humans cause as a sign that we're just the lowly spawn of Satan, sent to desecrate the Creation?

Are the widespread and diverse legends of "the little people," elves, dwarves, leprechauns, and such actually ancient folk memories of life among former relatives?

And the darkest question of all - did we kill them all off?


I don't have answers to these questions, though that's not surprising.  It's tough to deal with them intellectually while navigating such great depths of time and mystery, and it's also difficult emotionally to fully acknowledge that we've lost entire branches of humanity in the not-so-distant past.

Sometimes when I do grasp that absence, the world suddenly seems emptier and un-naturally quiet, as if I've fallen asleep in the midst of a party and then woken up to find most of my friends gone.  At other times, placing our people-cousins back onto the scale of human diversity where they belong seems to shrink the differences that we use to distinguish today's various ethnic/cultural groups from one another. 

Above all, I just enjoying thinking about this stuff. 

How about you, my fellow people-cousin?

Saturday, January 1, 2011

Hyenas should live in Paris

I just came across an interesting paper in Quaternary Science Reviews that also got some international press coverage when it came out last September, though I missed it at the time (this article is from Wired: http://www.wired.com/wiredscience/2010/09/what-killed-europes-hyenas/)

The main finding of the study was that spotted hyenas, the giggling hunter/scavengers that we normally think of as living in tropical Africa, also lived in much of Europe for the last million years or more, and they only vanished from those former haunts around the end of the last ice age when the mammoths and wooly rhinos that they coexisted with also died out. Their European range stretched from Spain to the Urals, meaning that they did well in seasonally chilly environments as well as in hot ones.  In other words, hyenas "should" still live in Europe.



Photo here by Silvain de Munck; Original article = Varela, S., Lobo, J., Rodríguez, J., & Batra, P. 2010. Were the Late Pleistocene climatic changes responsible for the disappearance of the European spotted hyena populations? Hindcasting a species geographic distribution across time. Quaternary Science Reviews, 29: 2027-2035

Two things come to mind, the first one being that this is just one more example of humans being implicated in mass extinctions.  Some scientists still argue that the charismatic "ice age" mammals must have died out because of climate change, but as I mentioned in an earlier post and as these authors clearly demonstrate, the weight of evidence strongly suggests otherwise.  If the end of the last ice age killed off Europe's hyenas, then how come they lasted at least a million years under similar conditions, and why do they still live in tropical Africa today?

But the second realization may be more important for modern times. As the authors point out, we tend to associate species with particular environments on the basis of where we find them today, and as we try to anticipate the effects of future climate change on animals and plants we may be misled if we forget that today's home ranges are not normal, either. 

Human activity has radically re-sculpted the distributions of countless species in recent centuries to millennia, so how can we be sure where species really COULD live if given the opportunity? Are some species actually more geographically adaptable than we think and, if so, which ones?

We run into this same kind of problem when some people claim that global warming will allow malaria to invade North America - without realizing that it's actually already native to this continent but has been extirpated by massive mosquito-control efforts (pesticides, window screens, etc.).

We also encounter it when some people present computerized predictions about the effects of future warming on North America trees and birds, such as the much-cited, interactive atlases offered online by the USDA Forest Service (http://www.nrs.fs.fed.us/atlas/).  Here, for example, is where sugar maples live today (left) and where they might prefer to live in a warmer future (right).



Such projections can seem impressive because they're based on "the latest super-computer models" and they make colorful, detailed maps of where sugar maples or loons supposedly may or may not exist in a warmer future.  But they all suffer from a core problem that's difficult to remedy in a world that's so heavily human-impacted; the supposed "normal" ranges are largely based on today's patchwork remnant of former ranges that don't necessarily reflect where species would live if our forebears hadn't shot/lumbered/burned/infected so many of their ancestors.

In the long run, the only thing we can be sure of in this regard is that future climates will differ from those of today (mostly being warmer than now for the next tens of thousands of years), and that human activity will continue to play a hugely powerful role in determining what lives where on the Future Earth.

Welcome, for better or for worse, to the "Anthropocene" - the Age of Humans.

And "Vive la hyène!"