What if evolution works 15,000 times faster than we imagined?
by tdaxp ~ December 14th, 2007
It was only eighteen months ago that I wrote a post titled “The implication of evolution after the dawn of agriculture.” At the time, I was startled by the idea that there may have been evolutionary change within the human population in the last four centuries. Also at the time I was highly impressed by Evolutionary Psychology evolutionary functional analysis, and the concept of the Era of Evolutionary Adaption.
Not this quick. But quicker
Since that time I have learned more about how biology informs the social sciences. It appears that evolution is faster than I thought, and Evolutionary Psychology is weaker than I assumed.
Go fast
Up until recently, the theoretical maximum speed for one gene to replace all other variations was one every 300 generations. It now appears the rate among humans is 2 every year. If this result holds up, this has important implications.
Two dynamics appear to be driving the acceleration of natural selection among humans: larger population size (more mutations are given a chance to rise up) and the even quicker evolution of culture (preventing the establishment of an equilibrium optimal genetic state).
Evolutionary Psychology is wrong because there is no species-wide “Era of Evolutionary Adaption.” Indeed, one wonders if the term “Era of Evolutionary Adaption” even makes sense. If it does, are EEAs of populations that had possessed agriculture for a very long time (say, the peoples of the fertile crescent, and Chinese and Indians of the great river valleys) far more agrarian than the EEAs of traditionally hunter-gatherer societies?
Further, as both cultural complexity and breeding population (both in numbers in and genetic diversity) vary historically, might one say that the Era of Evolutionary Adaption of Australian Aborigines is tens of thousands of years deeper in time than that of Indus River Valley dwellers?
Both the population of man and the culture of man have been growing at faster and faster rates. The implication of this is clear.
The 19th century saw more natural selection in our species than any other century, ever.
The 20th century saw more natural selection in our species than any other century, ever.
The 21st century will see more natural selection in oru species than any other century, ever.
And that’s not counting genetic engineering.
(Thanks to Sean, DMH, Fulwider, Doug, and others for not letting me get past this discovery without thinking it through.)
December 15th, 2007 at 12:00 am
Michael,
I'm not aware of a similar study on chimpanzees, but its usefulness is clear. Good point bringing it up.
The original article examined European, African, Han Chinese, and Japanese populations. Most of the “accelerated selection Variants” (ASVs) are race-specific, — while 1,800 genes appear to be ASVs, for example, only 509 are shared between Europeans and Africans, for example.
You can also find historically different rates of positive selection in the second and third chart from the article, which I included in the post.
But even if there are no group differences, Evolutionary Psychology assumes that the humans are adapted to the Pleistocene… perhaps, but the rapid increase in natural selection in the past 10,000 years argues that many adaptions may be specific to agricultural societies.
December 15th, 2007 at 12:00 am
2 questions come to mind (bear in mind it's 1AM here and I don't know a huge amount about genetics):
1. Has anyone looked at the rates of genetic change in chimpanzees or other animals to see if they show similar acceleration?
2. Has this data been broken down by specific ethnicities, nationalities, Y or mitochondrial DNA lines? If not, could you explain what evidence against evolutionary psych I'm overlooking here?
Again, not intending to be cranky or superior here, just tired and puzzled.
December 15th, 2007 at 12:00 am
Fascinating! (Really, I have nothing to add…I just want to subscribe to any updates).
December 15th, 2007 at 12:00 am
Dan
I love the way your mind works – it's such fun reading your material. I worry about my home as I read this. On Prince Edward Island, the most adventurous people have left the Island for the last 150 years. With the collapse of local subsistence agriculture many of those that have stayed have been drawn into a culture of living on government hand outs.
So now we have the worst educational outcomes and the worst health outcomes of any province in Canada.
What do you think may be the risks of humans in certain social conditions going backwards?
December 15th, 2007 at 12:00 am
PurpleSlog,
Thanks!
I've been following p-ter over at gnxp [1]…
Rob,
“What do you think may be the risks of humans in certain social conditions going backwards?”
Certainly, it's possible for social forms to warp into something very different, and probably worse.
One example is sometimes known as a “female farming” societies. In these, adult males largely abandon economically productive activities, instead devoting themselves to violent, hierarchical, relationships and ostentatious displays of wealth. Such societies are widespread in Africa, North Korea, and in many urban areas in the United States.
[1] http://www.gnxp.com/blog/2007/12/more-notes-on-acceleration.php