Wednesday, May 27, 2009

Vaccine Wars: The Phantom Menace

It's been 9 months since I read Autism's False Prophets and participated in a discussion over at Science Blogs Book Club. The good news is that there is increased awareness of the overwhelming scientific evidence refutating a link between vaccines and autism. Many organizations including the CDC, the Courts and the National Academy of Science, have all rejected a link between vaccines and autism.

There's even a Jenny McCarthy Body Count. (Former playmate Jenny McCarthy is the most prominent of the anti-vaccine advocates).

So why is the anti-vaccine movement still strong? Oprah has notably given Jenny McCarthy a highly visible platform. Despite overwhelming evidence that vaccines don't cause autism, one in four Americans still think they do. This has led to upsurges in measles, mumps and whooping cough among other easily preventable diseases. Large numbers of unvaccinated kids are dropping the population immunity below the herd immunity threshold for many diseases.

A great article investigating this tragedy is now available at PLoS Biology.

As the article points out, there is a conflict between individual interests and community interests. Pediatrician Jeffrey Baker says that "parents who claim nonmedical exemptions seem to become so focused on their own children that they “lose the bigger picture,” not accepting responsibility for the impacts their actions may have on the health of the community."

Autism's False Prophet's author Paul Offit blames "the media for keeping the myth alive by following the journalistic mantra of ‘balance,’ perpetually presenting two sides of an issue even when only one side is supported by the science. And shows like “Larry King Live” have been “just awful on this issue,” he adds, placing ratings and controversy above public health by repeatedly giving McCarthy and other “true believers” a platform to peddle fear and misinformation."

Medical anthropologist Sharon Kauffman thinks that the easy access to information online has exacerbated the crisis. Kaufman says, “many parents see even the most respected vaccine experts' perspective on the issue as just one more opinion.”

Article author Liza Gross writes, "Scientists on TV and radio are hard-pressed to compete with the emotional appeals of activists....McCarthy emerged as a hero for some parents by telling her story. Personal stories resonate most with those who see trust in experts as a risk in itself—a possibility whenever people must grapple with science-based decisions that affect them, whether they're asked to make sacrifices to help curb global warming or vaccinate their kids for public health. Researchers might consider taking a page out of the hero's handbook by embracing the power of stories—that is, adding a bit of drama—to show that even though scientists can't say just what causes autism or how to prevent it, the evidence tells us not to blame vaccines. As news of epidemics spreads along with newly unfettered infectious diseases, those clinging to doubt about vaccines may come to realize that several potentially deadly diseases are just a plane ride, or playground, away—and that vaccines really do save lives.

"Embracing the power of stories" sounds like framing to me. The notion was abhorrent to me when I first read the Nisbit and Mooney article, but lately I've been feeling less certain regarding the role of scientists in their intersection with the media.

Gross, L. (2009). A Broken Trust: Lessons from the Vaccine–Autism Wars PLoS Biology, 7 (5) DOI: 10.1371/journal.pbio.1000114

Wednesday, May 20, 2009

Scientia Pro Publica #4 - In Memory of Stephen Jay Gould

Stephen Jay Gould is my homeboy. True story, he grew up in my present hometown of Bayside, NY. I am honored to be included in a blog carnival in his memory: Scientia Pro Publica #4.

I never met SJG, but I did bump into him once. Literally! When I was a junior in college, I visited MCZ at Harvard on my way to the Ernst Mayr Library. (Back in olden days, we didn't have access to "online" articles. If you wanted an article, you had to go to the library and photocopy it from a bound volume.) As I was climbing the stairs to the library, a door swung open and SJG came barreling out, and collided with me. He hardly hesitated save to glance back and scowl at me. Or maybe it was a look of surprise. Hard to say since it happened so fast. I haven't been so thrilled to see a celebrity since the time I sat next to Bobby Orr at a hockey game.

Tuesday, May 19, 2009

Missing Link Found?

Franzen et al. announced the discovery of the most complete transitional fossil primate ever found. The fossil, described as Darwinius masillae, shows prosimian characteristics (e.g. a grooming claw on the second digit of the foot, and a fused row of teeth in the middle of her lower jaw known as a toothcomb), but has toe and fingernails, opposable thumbs, and a humanlike talus bone.

The Conclusions/Significance section of the abstract tells us,

Darwinius masillae represents the most complete fossil primate ever found, including both skeleton, soft body outline and contents of the digestive tract. Study of all these features allows a fairly complete reconstruction of life history, locomotion, and diet. Any future study of Eocene-Oligocene primates should benefit from information preserved in the Darwinius holotype. Of particular importance to phylogenetic studies, the absence of a toilet claw and a toothcomb demonstrates that Darwinius masillae is not simply a fossil lemur, but part of a larger group of primates, Adapoidea, representative of the early haplorhine diversification.
The announcement accompanies a veritable "media tsunami", including a American Museum of Natural History unveiling, a New York Times article, and a two-hour documentary to be broadcast on the History Channel on Memorial Day (May 25th).

Hype? Uberhype?

Probably, but I am withholding judgment until I find out more about it. Generally speaking, I am in favor greater public awareness of transitional evolutionary fossils. Even if this turns out to be somewhat inaccurate, and the precise phylogenetic position isn't directly linked to man, it will still raise awareness of evolutionary theory among an ill-educated public.

Franzen, J., Gingerich, P., Habersetzer, J., Hurum, J., von Koenigswald, W., & Smith, B. (2009). Complete Primate Skeleton from the Middle Eocene of Messel in Germany: Morphology and Paleobiology PLoS ONE, 4 (5) DOI: 10.1371/journal.pone.0005723

Saturday, May 16, 2009

The Giant’s Shoulders #11

The Giant's Shoulders #11 is up at Curving Normality. This month's issue has excellent reads from Schrodinger, Faraday, Darwin, et al. I particularly liked the article by Eric Michael Johnson, who blogs at The Primate Diaries. In the article, Rivalry Among the Reefs, Johnson writes about Darwin's little known coral reef work.

Coral reefs hold an important place in the history of evolutionary theory, as they were the subject of Darwin’s first scientific monograph and his official entrance into the scientific community. It was this research, and his eight-year study of barnacles, that led to the Royal Society awarding him the Copley Medal for outstanding achievement in science. Based on depth measurements taken of the coral reefs at Cook, Keeling and Mauritius Islands, Darwin developed his theory of “subsidence” to explain their development. Darwin didn’t know just how coral reefs grew, but he was aware that the living coral formed fringing reefs just below sea level along many coastlines. He was also aware of white strips of limestone that encircled volcanoes throughout the South Pacific. Darwin theorized that these were the remnants of fringing reefs that had been raised above sea level by the rising volcano. The same logic should therefore operate in reverse; if the coast were sinking then the coral would continue to grow upwards in order to remain in the warm, sunlit waters. Eventually, once the coastline was completely submerged, all that would remain would be the coral atoll. After arguing away every problem that had previously plagued coral reef formation, Darwin was left with his triumphant conclusion.

"On this view every difficulty vanishes; fringing-reefs are thus converted into barrier-reefs; and barrier-reefs, when encircling islands, are thus converted into atolls, the instant the last pinnacle of land sinks beneath the surface of the ocean."
Darwin was later shown to be correct by Dr. Harry Ladd, a researcher for the US Geological Survey. Ladd convinced the US War Department to drill holes deep into the Bikini and Eniwetok Atolls just prior to their obliteration in 1952 by hydrogen bombs.
After digging nearly 5,000 feet through the coral of Eniwetok Atoll, the drill finally passed through and hit pay dirt. The atoll had been built up from coral as the land had sunk from view, just as the theory of subsidence had predicted. Tiny organisms, just millimeters across, had pulled themselves up by their own bootstraps to create the largest natural structures ever created by a living being. Just next to the borehole that ended the debate, Ladd erected a small sign that still stands today. It reads, simply “Darwin was right!
Figure: Darwin's drawing of a reef from Voyage of the Beagle.

Sunday, May 10, 2009

Evolver Zone

University of Guelph Professor Ryan Gregory's Evolver Zone is now online. Evolver Zone is a one-stop shop for everything evolution related.

EZ contains links to multimedia, software, databases, professional societies, journals, and books, with new content added regularly. The site is 100% free to use, but is subsidized by the sale of original evolution related merchandise available through the EZ store. Any surplus funds will be used to support student research.

Content should be useful to everyone from the casual student to the professional scientist. Kudos to Dr. Gregory.

Wednesday, May 6, 2009

Homo floresiensis: Our Clown-footed Cousins

I was fascinated by the discovery of the dwarfed hominin Homo floresiensis back in 2004 when it was first announced, but was skeptical that it was really a separate species. Later when I saw a cast of the skull, I admit to being more enthused with the possibility of a new species. Not being a anthropologist, I couldn't discount the possibility of microcephaly and/or dwarfism.

However, a recent pair of articles in Nature discount this possibility, and I'm convinced. Jungers et al. analyzed the H. floresiensis foot and report that it is quite unhumanlike. For a meter-high hominin, it sure has a big foot! At 20 cm, it is much longer than would be expected for a proportionately smaller human. In fact, the foot is much closer in length to that of a chimpanzee.

I think it is pretty unlikely that, if island dwarfism or microcephaly were the cause, the creature would have showed smaller features except for the feet. In other words, all features should have been reduced proportionately.

So if it isn't human, what is it? Most wagers are on a descendent of H. erectus. A close relationship of H. floresiensis with H. erectus is to be expected. H. erectus is believed to be the first hominim to leave Africa (ca 2 mya). In fact, the first H. erectus found was Dubois' Java Man (Java is ~1000 km from Flores). It is not a stretch to speculate that H. erectus arrived on Flores, was isolated, and evolved smaller stature over time, thus becoming H. floresiensis, a contemporary of modern man.

However, additional primitive features of the foot, such as long, curved and robust lateral toes; a short big toe; and a weight-bearing process on a crucial bone, imply that H. floresiensis was better suited for walking than running. This feature is important because modern feet first appeared in H. erectus, thus suggesting that H. floresiensis split off from H. erectus before the evolution of the modern foot.

Other primitive anatomical features, such as a relatively short, very curved clavicle; a straight humerus that lacked the normal degree of twisting between the shoulder and the elbow; an ape-like wrist; flared iliac blades, relatively small joints and relatively short leg bones, all imply a close relationship to early Homo or even Australopithecines.

If the article is to be believed in full, and this is the point I have most difficulty swallowing,

"these new findings raise the possibility that the ancestor of H. floresiensis was not Homo erectus but instead some other, more primitive, hominin whose dispersal into southeast Asia is still undocumented."

So we have another possible Out of Africa event! First, H. floresiensis (or its immediate ancestor). Then H. erectus. Then H. sapiens.

Jungers, W., Harcourt-Smith, W., Wunderlich, R., Tocheri, M., Larson, S., Sutikna, T., Due, R., & Morwood, M. (2009). The foot of Homo floresiensis Nature, 459 (7243), 81-84 DOI: 10.1038/nature07989

Friday, May 1, 2009

Biology of B-Movie Monsters

One of the tragedies of the Hollywood movie industry is that they don't make "so bad they are funny movies" anymore. Sure they make plenty of mediocre movies, bad movies, "so bad you want to pluck your eyes out movies" and occasionally even good movies, but the "so bad they are good movies" are a lost art. They were a perfect storm of low production values, wildly contrived plots, abysmal writing, and budgets running into the hundreds of dollars.

Representatives of this genre include The Incredible Shrinking Man, Godzilla vs. Mothra, Plan 9 from Outer Space, Fire Maidens from Outer Space (the "from Outer Space" is a genre of its own), and Fantastic Voyage. A common feature of these movies was a complete and utter disregard for the Laws of Physics, Biology, Chemistry or other intellectual endeavor. If it can be imagined, no matter how fantastic, somebody probably made it a central plot point for a movie in the 50's.

It was to my great surprise that someone actually considered the biological implications of these old B-Movies. I give you "The Biology of B-Movie Monsters" by Michael C. LaBarbera.

Remember the scene in The Incredible Shrinking Man, where our hero fights a giant sized spider. Turns out it would have been no contest.

"As for the contest with the spider, the battle is indeed biased, but not the way the movie would have you believe. Certainly the spider has a wicked set of poison fangs and some advantage because it wears its skeleton on the outside, where it can function as armor. But our hero, because of his increased metabolic rate, will be bouncing around like a mouse on amphetamines. He wouldn't struggle to lift the sewing needle--he'd wield it like a rapier because his relative strength has increased about 70 fold. The forces that a muscle can produce are proportional to its cross-sectional area (length squared), while body mass is proportional to volume (length cubed). The ratio of an animal's ability to generate force to its body mass scales approximately as 1/length; smaller animals are proportionally stronger. This geometric truth explains why an ant can famously life 50 times its body weight, while we can barely get the groceries up the stairs; were we the size of ants, we could lift 50 times our body weight, too. As for the Shrinking Man, pity the poor spider."
Michael C. LaBarbera is a professor in Organismal Biology & Anatomy, Geophysical Sciences, the Committee on Evolutionary Biology, and the College of the University of Chicago.