RE: Homo evolutis
June 30, 2016 at 7:31 am
(This post was last modified: June 30, 2016 at 7:51 am by Anomalocaris.)
(June 29, 2016 at 5:26 am)chimp3 Wrote: What do you think of the idea that we are evolving into a new species named Homo evolutis ? The first species to take command of it's own evolutionary future? I can think of one simple proof this may be happening. Vaccination against disease. Is modern medicine our extended phenotype?
Vaccination against disease definitely have an impact on the human genome. It allows those who are genetically more vulnerable to fatal or sterilizing diseases to compete on an equal footing as those are more genetically more resistant or immune to these. So in the long run it prevent certain genes from dying out, and other genes from gaining dominance in the gene pool.
However, this does not lead to a new species. It simply shapes the overall composition of the entire human gene pool.
The fact the people of different social economic and ethnic background may reproduce at different rates, also only has potential to change the composition of the overall gene pool, and do not lead to speciation.
To create a new species, one would require some parts of the population to undergo long period of reproductive isolation, so that the any change in the isolated gene pool can not propagate back to other parts of the population. Only this way can genetic different between different part of the population accumulate, until eventually the total amount exceeds some threshold and speciation occurs.
Earlier someone mentioned a new species might occur after 10000 years of separation via interstellar travel. It would appear that is not nearly enough. Native American population had been genetically almost completely separated from the rest of Homo sapiens for at least 12000 years, and they started with a very small and particular gene pool. But they have not come anywhere remotely approaching to speciating after 12,000 years
Genetic changes occurs not only as function of selective pressure, but also as function of generations. But humans are a comparatively long lived and slow breeding specie. So each generation takes longer and speciation also correspondingly likely take longer in humans than in squirrels or finches. Evidence suggest fertile interbreeding had remained possible between members of the homo genus after many hundreds of thousands of years of separation. So For natural speciation to happen from within the homosapien population, due to such things as geographic separation, or separation via interstellar travel, one probably needs to think in terms hundred of thousands of years, not thousands or tens of thousands.
