Archive for May 23rd, 2010
In the Wall Street Journal, Matt Ridley argues that human beings haven’t flourished because of anything we do individually. Rather, it is our ability to share and to building upon previous ideas of others–it is our “collective intelligence”:
The notion that exchange stimulated innovation by bringing together different ideas has a close parallel in biological evolution. The Darwinian process by which creatures change depends crucially on sexual reproduction, which brings together mutations from different lineages. Without sex, the best mutations defeat the second best, which then get lost to posterity. With sex, they come together and join the same team. So sex makes evolution a collective and cumulative process in which any individual can draw on the gene pool of the whole species. And when it comes to gene pools, the species with gene lakes generally do better than the ones with gene ponds—hence the vulnerability of island species to competition with continental ones.
It is precisely the same in cultural evolution. Trade is to culture as sex is to biology. Exchange makes cultural change collective and cumulative. It becomes possible to draw upon inventions made throughout society, not just in your neighborhood. The rate of cultural and economic progress depends on the rate at which ideas are having sex. . . . So here is the answer to the puzzle of human takeoff. It was caused by the invention of a collective brain itself made possible by the invention of exchange. . . . Prosperity consists of getting more and more narrow in what you make and more and more diverse in what you buy. Self-sufficiency—subsistence—is poverty.
Ridley concludes that this inexorable building upon prior ideas by sharing them is ultimately a “cheery” one (he points to reduced child mortality and increased per capita income worldwide), despite the occasional setbacks.
Scientific convention used to be that modern humans came out of Africa and completely replaced Neandertals (also spelled “Neanderthals”) without interbreeding (for example, see here). New evidence suggests that this hypothesis is incorrect, according to an article by Ann Gibbons called “Close Encounters of the Prehistoric Kind.” The article appears in the May 7, 2010 edition of Science (available online only to subscribers). An international team has now completed the draft sequence of the Neandertal genome, which includes more than 3 billion nucleotides collected from the bones of three female Neandertals who lived in Croatia more than 38,000 years ago.” The analysis described was astoundingly complex, and the consequences of this analysis are startling:
By comparing this composite Neandertal genome with the complete genomes of five living humans from different parts of the world, researchers found that both Europeans and Asians share 1% to 4% of their nuclear DNA with Neandertals. But Africans do not. This suggests that early modern humans interbred with Neandertals after moderns left Africa, but before they spread into Asia and Europe. The evidence showing interbreeding is “incontrovertible,” says paleoanthropologist John Hawks of the University of Wisconsin, Madison, who was not involved in the work. “There’s no other way you can explain this.”
Therefore, many people living outside of Africa carry “a small but significant amount of DNA from these extinct humans.” The consequences of this amazing finding are not lost on anyone:
In a sense, the Neandertals are then not altogether extinct, says lead author Svante Paabo, a paleogeneticist at the Max Planck Institute for evolutionary anthropology in Leipzig Germany, who is surprised to find out he was part Neanderthal. “They live on in some of us.”
The Science article presents the following list of things we now know about Neanderthals:
- The genomes of modern humans and Neanderthals are 99.84% identical.
- The scientific data don’t support interbreeding when scientists had most expected it (between 45,000 and 30,000 years ago in Europe).
- Neanderthals coexisted with modern humans in Europe from 30,000 to 45,000 years ago, and perhaps in the Middle East as early as 80,000 years ago.
- The amount of admixture is tiny, even among Europeans and Asians, but Neanderthals “are significantly more closely related to non-Africans than Africans on average.
- The new data fits with the discovery of fossils and stone tools from Israel caves about 80,000 years ago (modern humans and Neanderthals both used these caves and had much in common–they used similar tool-kits and under the same animals). One Neandertal skeleton from the Middle East looked “less robust than Neanderthals in Asia and Europe.
- Despite the ability to sequence some Neanderthal DNA, there is no possibility of cloning a Neanderthal.
- “The isolated DNA was in pieces typically about 50 bases long, and there were many missing stretches. Further, despite the story one often hears in the mass media, DNA is not completely responsible for the appearance of an animal. “Chemical modifications to the genome, the way chromosomes arrange in the nucleus, and maternal components in the egg all play a role in translating a genetic blueprint into a viable individual.” None of these are available with regard to Neanderthals. As soon as you substitute another oocyte (e.g., that of a modern human) for that of a Neandertal, you would change the resulting organism.
Despite the fact that there was some interbreeding, it did not happen much. This article quotes evolutionary geneticist Sarah Tishkoff, who asked “Was it a cultural barrier?”
We are cousins with every living thing on planet Earth (including trees and see here), but many of us are both cousins and descendants of Neandertals. Therefore, for those of you who have had ancestors from anywhere outside of Africa (keeping in mind that all of us have ancestors from Africa), you are African and you are Neandertal. I’m planning on having a bit of fun the next time a bureaucratic form requires me to designate my “race.”
I am often asked, “Why do you fight against religion?” Today my answer would be best expressed by this article from the New York Times.
A new documentary called “Saving Africa’s Witch Children” will be airing Wednesday May 26th on HBO2.
The documentary follows Gary Foxcroft…
…founder of the charity Stepping Stones Nigeria, as he travels the rural state of Akwa Ibom, rescuing children abused during horrific “exorcisms” — splashed with acid, buried alive, dipped in fire — or abandoned roadside, cast out of their villages because some itinerant preacher called them possessed.
One of the main subjects of the documentary is Helen Ukpabio.
At home in Nigeria, the Pentecostal preacher Helen Ukpabio draws thousands to her revival meetings. Last August, when she had herself consecrated Christendom’s first “lady apostle,” Nigerian politicians and Nollywood actors attended the ceremony. Her books and DVDs, which explain how Satan possesses children, are widely known.
So well-known, in fact, that Ms. Ukpabio’s critics say her teachings have contributed to the torture or abandonment of thousands of Nigerian children — including infants and toddlers — suspected of being witches and warlocks.
If ever there was a reason to continue to strive to undermine the authority of religion, this is it.