From: Wei Dai (weidai@eskimo.com)
Date: Thu Apr 04 2002 - 16:49:27 MST
On Wed, Apr 03, 2002 at 07:38:43PM -0500, CurtAdams@aol.com wrote:
> Until recently, more children meant fewer resources for the rest and
> a consequent decreased survival. While data on historical humans is
> lacking, it's a good rule for any creature that its fecundity is near
> optimal. So alleles for increased fecundity had both benefits and costs.
> Now survival is almost 100% regardless of how many kids you have.
> Increased fecundity is now just gravy for the genes.
I think what's relevant here is not the relative frequencies of the
alleles, but the relative amounts of resources they have access to. Today
having more babies gives you more offsprings that survive into maturity,
but it's not clear that it increases the total wealth/power of your
offsprings compared to having fewer babies (because it causes you to
invest less in each offspring and the return on that investment is
increasing up to a point). If it doesn't then increased fecundity is going
to be a losing strategy in the long run.
> It wasn't a change in genes that caused the transition, but a change
> in culture. However, the lower reproduction due to those
> shift is going to be partly caused by pre-existing genes, (virtually
> anything about humans has both genetic and cultural components) and
> those genes now face huge negative selection pressure. When they
> go away people will go back to having lots of babies.
Any guesses what genes are casuing the lower reproduction?
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