[ExI] homo sapiens as endangered species
stefano.vaj at gmail.com
Fri Jun 3 11:41:40 UTC 2011
On 2 June 2011 21:33, Anders Sandberg <anders at aleph.se> wrote:
> Low genetic diversity is less of an issue than many think (but it
> contributes a bit). The real threat is demographic noise: a small population
> will have larger relative fluctuations, some of which can drive it down to
> even smaller and even more vulnerable. A species "circling the drain" can
> run into problems both with bad years, with few children due to bad luck,
> bad luck with gender ratios, Allee effects and a bunch of other things.
> In my sims I need about 2000 people to get long term survival with more
> than 90% probability. Smaller populations can survive, but they need to be
OTOH, speciation happens exactly out of the genetic drift which in principle
affects the smallest, and reproductively most segregated, populations. In
turn, diversity arises again in the new species as a consequence of
mutations and selective pressures acting on larger numbers as soon as they
can be re-established.
Let us just say that the seed has to be very lucky to become a tree.
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the extropy-chat