The 10,000 Year Explosion: Has Human Civilization Turbo Charged Evolution?

 

“It was the failures who had always won, but by the time they won they had come to be called successes. This is the final paradox, which men call evolution.”

Loren Eiseley -The Immense Journey

According to most theories of human evolution, the species became “behaviorally modern” some 50,000 years ago and has not evolved much genetically since then. But according to a controversial new book, The 10,000 Year Explosion, human civilization has actually turbo changed our evolution.

Gregory Cochran and Henry  dispute the late Stephen Jay Gould’s assertion that civilization was “built with the same body and brain” Homo sapiens has had for 40,000 years. Humanity has been evolving  dramatically for the last 10,000 years, they say, spurred by the very civilizational forces launched by that evolution.

The 10,000 Year Explosion is a work of genetic history that gives full treatment to the evolutionary power of natural selection in shaping human history. For example, how did the Indo-European language family get to be so geographically expansive? There is the story of how lactose tolerant Indo-Europeans spread milk-drinking with blood and fire, why the Ashkenazi suffer from crippling genetic diseases at an unexpectedly high rate while winning 25% of Nobel Prizes in the last century, and how the Spanish destroyed the Aztecs and the Incas. The real accidents of history are matters of gene flow and chance mutation.

Posted by Casey Kazan.

Related Galaxy posts:

Homo Sapiens -The "Time Travelers" -A Galaxy Classic
“Hyper-Speed” Evolution Discovered
Bringing Ancient Human Viruses Back to Life: A Jurassic Park or Salvation?

Immense Journey

Comments

[Andrew]

Really neat stuff. But wouldn't this be almost a separate version of natural selection in that civilizations would represent mega-organisms much like ant or termite colonies? Possibly going into the future this could become somewhat moot if more and more of the world population becomes of mixed race and "hybrid heartiness" begins to take hold. Just a thought.

[Marshall]

Andrew--not really sure what you're saying. Why would civilizations represent mega-organisms? They simply represent populations of humans, or local gene pools. The same is true for all species that, almost without exception, physical distance is a very good indicator for genetic relatedness.

I think you're trying to say that the actual process of selection is now something that shifted from nature-based to community-based. Throughout history, most species are selected for and against based on the environment and competing species--predators, food available, weather, temperature, and food sources. Much of the selection that occurs among humans is civilization-based. It's not really physical (although much of it is genetically based and thus indirectly physical), but more cognitive decisions based on ideology, discrimination, and community.

[Mike]

This book was fun to read because much of the speculation in it is so ridiculous. And it is rife with speculation. Bushmen have a hard time adapting to life as shepards - it must be genetic. Odd, I have the same problem learning Manderin: Is that genetic too? Tay-Sachs and Gaucher's exist at such high frequencies amongst Jews and everyone knows Jews are smart; heterozygous Jews must be smarter than the rest of us. Oddly, Tay-sachs heterozygosity hasn't had the same impact on French-Canadians and Cajun populations, which also have high frequencies of the disease alleles, or among the Irish who have very high levels of phenotypic heterzygousity. Gaucher's heterozygousity is likely to be advantageous in environments that have frequent outbreaks of influenza and TB (if you're familiar with Pubmed, do some searches to find out how Gaucher's affects the immune system). Just a few years ago the author's of the book were hailing the discovery of a new allele for the microencephlin gene that emerged around 40,000 yrs ago. Since microencephlin is known to have an impact on brain size the emergence of this allele must be one of the reasons Europeans are so smart. Unfortunately, it's now been clearly demonstrated that the allele has no impact on IQ. It's also strange that the authors never mention the Flynn effect (raw IQ scores among populations tend to increase with each passing generation; the Flynn effect has been correlated with urbanization and family literacy). The book is worth reading if you're reasonably well-informed and don't just take the authors' word for it when they express an opinion.

[gcochran]

At least we knew how to spell heterozygosity. You know, I had hoped for criticism that either had some merit or was just plain fun, as when someone once said that I was "descending into the most disturbing depths of madness and the most depraved abuse of science yet conceived"

Makes you feel humble and kinda proud. But hearing something boring from yet another innumerate biologist is just sad.

[Jason Adam]

I'd say its pretty evident we have!

RT
www.whos-watching.se.tc

[gendou]

I take issue with the claim that the human species "has not evolved much genetically since" 50,000 years ago. Any biologist will tell you that selection forces are always at work, there's no reason humans would be an exception. I'd like to hear what an anthropological archeologist would have to say about changes in morphology in the last 50,000 years.

[Viewer]

"It's also strange that the authors never mention the Flynn effect (raw IQ scores among populations tend to increase with each passing generation; the Flynn effect has been correlated with urbanization and family literacy)."

Reaction time tests can produce a very highly g loaded discrimination, yet chronometric measures have not been shown to change over decades.The Flynn effect is likely to have many components. Nutrition is probably one of the several contributors although improvements in scores have tended to be domain specific. In 1987 Flynn published a paper that showed the largest gains were on the Raven's tests. He has found little, if any, gain in vocabulary.

It is well known that FE (Flynn Effect) gains have been greatest in tests of abstract reasoning and least in tests that relate to scholastic items. This contrast immediately suggests that the FE gains have not been g loaded, since g loaded gains would necessarily boost all cognitive tasks. The problem here is that it is g loading that matters. Most studies that have attempted to measure the g loading of the gains have shown little or no loading.

Also, the Flynn effect doesn't show gaps between groups closing. For instance, East Asians average above Europeans and Ashkenazi Jews average about 2/3 of a std dev above the European mean. Environmentalists have argued that gaps will close, but no evidence has surfaced to show that after decades of rise that they will.

Interestingly, in some places the trend has stopped, for instance in Scandinavia there has been a recent slight reversal (IQ decrease).

"Bushmen have a hard time adapting to life as shepherds - it must be genetic. Odd, I have the same problem learning Mandarin: Is that genetic too?"

I think the point is that groups may have different traits on average due to different evolutionary paths. For instance, with agriculture there have been metabolic/diet changes like lactose tolerance, many changes in genes involved with defense against infectious disease, many changes in genes that affect hearing and smell, changes in neurotransmitters and related genes that most likely influence personality, changes in genes involved with the regulation of nerve connections and brain growth. For example, you see new versions of SLC6A4, a serotonin transporter, in Europeans and Asians.

There's a new version of a gene (DBA1) that shapes the development of the layers of the cerebral cortex in east Asia. It is interesting though that a number of these recent changes seem to affect neurological function, although exactly how isn't entirely clear. Here's another interesting one:

"The protein encoded by DAB1 plays a developmental role in the layering of neurons in the cerebral cortex and cerebellum [37], and exhibits strong evidence for a selective sweep in the Asian sample." 'Localizing Recent Adaptive Evolution in the Human Genome,' Williamson SH, Hubisz MJ, Clark AG, Payseur BA, Bustamante CD, et al. 2007 Localizing Recent Adaptive Evolution in the Human Genome. PLoS Genet 3(6): e90. doi:10.1371/journal.pgen.0030090

[Meranaamhai]

10,000 years are too little to have any effect on our basic genetic make-up. Civilization began with surplus food production and agriculture. Surprise, surprise, that too happened at about the same time!

[katesisco]

RMP's Vital Vastness is chock full of info and his theory is that the Earth has a fissioning core and at full throttle has an accompanying 'umbrella' of ion particles that spew up from the center of each of the 12 fields, high enough to avoid their dispersal onto the Earth WHEN everything is working right, which it is not now.

I love his question: why are the seas still at 3.4% salt and have been since time immorial---why hasn't the salt load built up, especially since now we find contamination due to us everywhere now.

[anish]

i was asking the history of the turbo charger and how its changed from when it was made lolz