born to run

Evolutionary bio and marathon running, at Seed magazine.

We know that roughly 2 million years ago, Australopithecus, with its tiny brain, hefty jaw and diet of rough, fibrous plants, evolved into Homo erectus, our slim, long-legged ancestor with a big brain and small teeth suited for tearing into animal and fruit flesh. Such a transformation almost certainly involved a reliable supply of calorie-laden meat, yet according to the fossil record, spear points have been in use for 200,000 years at most, and the bow and arrow for only 50,000 years, leaving an enormous stretch of time when early humans were consuming meat without the use of tools. Lieberman believes they ran their prey to death, often called “persistence hunting.”

Interesting and usable.

150,000 year split

NatGeo (GAAAAH! Now I'm doing it!) presents another article about the genetic split in homo sapiens -- adding the fact that the population seems to have dropped to around 2,000 total people between the two groups. Crazy.

Shoes bad, feet good.

It took four million years to evolve the perfect human foot. And we've gone and thrown it all away!! (New York Magazine, "You Walk Wrong")

“Natural gait is biomechanically impossible for any shoe-wearing person,” wrote Dr. William A. Rossi in a 1999 article in Podiatry Management. “It took 4 million years to develop our unique human foot and our consequent distinctive form of gait, a remarkable feat of bioengineering. Yet, in only a few thousand years, and with one carelessly designed instrument, our shoes, we have warped the pure anatomical form of human gait, obstructing its engineering efficiency, afflicting it with strains and stresses and denying it its natural grace of form and ease of movement head to foot.” In other words: Feet good. Shoes bad.

In other evolution news, some interesting new evidence of divergence in human gene pool -- before it then re-merged. BBC: "Human line 'nearly split in two'" relays finding from the American Journal of Human Genetics. Basically, 150,000 years ago a population split off and inhabited southern Africa, where they lived in isolation from the east African group for 50-100,000 years:

Dr Wells told BBC News: "Once this population reached southern Africa, it was cut off from the eastern African population by these drought events which were on the route between them."

Modern humans are often presumed to have originated in East Africa and then spread out to populate other areas. But the data could equally support an origin in southern Africa followed by a migration to East and West Africa.

The genetic data show that populations came back together as a single, pan-African population about 40,000 years ago.

This renewed contact appears to coincide with the development of more advanced stone tool technology and may have been helped by more favourable environmental conditions.

Neat.

Expelled!

Not recorded much of this controversy (or much of anything recently at the end of this semester), but this link from Richard Dawkins (courtesy PZ Myers' "Appropriate Responses to Expelled") shoots down in perfect form the supposed connection between Nazis and Darwin. Which, Nazis being one of my things, would be handy to have around for future needs.

Though in a way, all one might have to say on the subject is that in all of Mein Kampf.... Hitler never mentioned Darwin. Some influence.

T-Rex cock!

Yes, that is an accurate description of this NYT article. ("A Tyrannical Romance" by Olivia Judson) It describes some thoughts on how you can read social behavior from sexual traits. Works for humans, works for dinos... kinda.

evolution of Brad Pitt

Semi-interesting article on the evolution of male facial features - "bulldog-like" the article describes, with pinched ratio between brow and chin compared to women. It evolved because women find it attractive, and hence propagated itself.

But the whole thing, at least as written up by this Yahoo news story (LiveScience.com actually) is a bit circular. Faces that have this ratio are 'more masculine' and therefore women are attracted to them. This attraction confirms its own premise. I dunno. And there could be other reasons for the ratio as well... who knows.

In any case it's interesting if the skulls show change over time that the feature did evolve, which seems to be the point.

1800 change in human nature

Now only if we could have a change in the nature of the human at 1600 (rimshot)

But in seriousness, here's a new article from the NYT Science section on the emerging industrial culture of the 19th century. One of his keys is the counterintuitive concept of "downward social mobility":

Generation after generation, the rich had more surviving children than the poor, his research showed. That meant there must have been constant downward social mobility as the poor failed to reproduce themselves and the progeny of the rich took over their occupations. “The modern population of the English is largely descended from the economic upper classes of the Middle Ages,” he concluded.

As the progeny of the rich pervaded all levels of society, Dr. Clark considered, the behaviors that made for wealth could have spread with them. He has documented that several aspects of what might now be called middle-class values changed significantly from the days of hunter gatherer societies to 1800. Work hours increased, literacy and numeracy rose, and the level of interpersonal violence dropped.

He has a lot about genetics that may take things a little too far. Doesn't seem like these values have to be encoded in genes for them to have the same effect. (And besides, evolution can't operate in that short a time period.) But it's an interesting thesis when read on the cultural / institutional level.

updated human timeline

The timeline of human evolution just got more complicated, as it does every few years or so.

The old theory was that the first and oldest species in our family tree, Homo habilis, evolved into Homo erectus, which then became us, Homo sapiens. But those two earlier species lived side-by-side about 1.5 million years ago in parts of Kenya for at least half a million years, Leakey and colleagues report in a paper published in Thursday's journal Nature.

Leakey's co-author notes that human evolution is a

"chaotic kind of looking evolutionary tree rather than this heroic march that you see with the cartoons of an early ancestor evolving into some intermediate and eventually unto us."

That's the point I'd want students to get out of this article. It's not a straight line, its many branches and dead ends.

Concerning Hobbits

More debate (via Panda's Thumb) on what exactly the deal was with Homo floresiensis - aka, the Hobbits discovered in Malaysia. Are they a different species, or just microcephalic humans (humans with small brain sizes)?

Professor Colin Groves of the Australian National University thinks the former, and has a 7-part YouTube series on the details. (Part 1 here) Panda's Thumb reports from a conference on the subject that the microcephalic theory seems to be failing, and most paleontologists are starting to come around to the separate species view.

Duck dongs

Best. Headline. Ever.

Hat tip to Salon's Broadsheet for relating new findings about duck genitals from the NYT. ("In Ducks, War of the Sexes Plays out in the Evolution of Genitalia" by Carl Zimmer)

Several interesting points, including the evolution of genitalia in and of itself, the fact that female ducks' complicated boxes seem to be that way in order to be able to capture and expel unwanted sperm from duck rape (1/3 of all duck sex!), and also that it was a (human) female researcher who discovered this new things about male ducks.

That last point reminds me of historical, sociological, etc. work on humans. Before the gender turn, male scholars ignored women, and discounted men as objects of study as men. Then women demanded that women be studied. Then, finally, these women prompted a study of men as well. Now of course men are in the game - but beyond some pioneers, men were largely absent from early gender work. Men's studies is still seen as a kook specialty, distrusted by both women (who see it as backward and patriarchal) and men (who see it as effeminate).