4 ms·

Yeah, seems more logical to say ancient human experienced a number genetic divergences which were then folded into the mainline of the genetic stream.

0x8BADF00D 7y ago
Environment plays a huge role. If a nomadic group was in a jungle-like environment, wouldn’t they more likely develop the traits of the other species well suited for jungle living? Over a long enough timescale.
- Haga 7y ago
  The habitat also swings, so behavior specialist sub species for every part of the cycle, which allow long term adjustment to circumstances by percentages would be quite beneficial.
- rjf72 7y ago
  Epigenetics is indicating that our traditional view of genetics is probably just completely wrong, but going with that traditional view - it's not that an environment changes a species, but randomness. And traits randomly evolved that end up beneficial are preserved in the lineage due to increased survivability. Jungle like environments tend to be extremely favorable for the survival of intelligent species which means natural selection starts to play less of a role. Well it does play a role, but in different ways. For instance modern humans are continuing to evolve even though natural selection, in terms of man against environment, is now playing very near 0 role. Instead the factor being selected for now is simple fertility. Humanity will tend to evolve along the characteristics of those families have 3, 4 and more children - while those having 2 or fewer children will gradually fade from the gene pool. So natural selection has in some ways become voluntary, which is quite paradoxical. However in less developed areas, it's still alive in some ways. For instance if an individual in subsahara Africa somehow developed a genetically heritable mutation making him immune to malaria, it's reasonably likely that all subsaharan Africans would, gradually, become immune to malaria. We can only conclude, putting aside epigenetic factors once again, that such mutations are much less common than e.g. those to the shape of a bird's beak.
- thaumasiotes 7y ago
  > If a nomadic group was in a jungle-like environment, wouldn’t they more likely develop the traits of the other species well suited for jungle living? Yes, and this has already happened. The African jungle has its pygmies; the Southeast Asian peninsula and surrounding islands have their pygmies; and those two groups are totally unrelated.
Sharlin 7y ago
Not at all. For instance, it is thought that H. sapiens × H. neanderthalis hybrids, while viable at least some of the time, were almost never fertile. To explain the Neanderthal contribution to the genome of modern humans, only a very low frequency of successful hybridization events is required.
keiru 7y ago
>mainline of the genetic stream This is a tricky concept. Could it be said over 50,000 years ago that Homo Sapiens' ancestors were the mainline? I wouldn't retroactively call it that because it presumes that it was clear at the time that it would be the definitive dominant subspecies. I think a better phrasing would be "genetic divergences, some of which were preserved by the cross-merging with the only surviving genetic stream", or something of the sort.

0x8BADF00D 7y ago

Environment plays a huge role. If a nomadic group was in a jungle-like environment, wouldn’t they more likely develop the traits of the other species well suited for jungle living? Over a long enough timescale.

Haga 7y ago
The habitat also swings, so behavior specialist sub species for every part of the cycle, which allow long term adjustment to circumstances by percentages would be quite beneficial.
rjf72 7y ago
Epigenetics is indicating that our traditional view of genetics is probably just completely wrong, but going with that traditional view - it's not that an environment changes a species, but randomness. And traits randomly evolved that end up beneficial are preserved in the lineage due to increased survivability. Jungle like environments tend to be extremely favorable for the survival of intelligent species which means natural selection starts to play less of a role. Well it does play a role, but in different ways. For instance modern humans are continuing to evolve even though natural selection, in terms of man against environment, is now playing very near 0 role. Instead the factor being selected for now is simple fertility. Humanity will tend to evolve along the characteristics of those families have 3, 4 and more children - while those having 2 or fewer children will gradually fade from the gene pool. So natural selection has in some ways become voluntary, which is quite paradoxical. However in less developed areas, it's still alive in some ways. For instance if an individual in subsahara Africa somehow developed a genetically heritable mutation making him immune to malaria, it's reasonably likely that all subsaharan Africans would, gradually, become immune to malaria. We can only conclude, putting aside epigenetic factors once again, that such mutations are much less common than e.g. those to the shape of a bird's beak.
thaumasiotes 7y ago
> If a nomadic group was in a jungle-like environment, wouldn’t they more likely develop the traits of the other species well suited for jungle living? Yes, and this has already happened. The African jungle has its pygmies; the Southeast Asian peninsula and surrounding islands have their pygmies; and those two groups are totally unrelated.

Sharlin 7y ago

Not at all. For instance, it is thought that H. sapiens × H. neanderthalis hybrids, while viable at least some of the time, were almost never fertile. To explain the Neanderthal contribution to the genome of modern humans, only a very low frequency of successful hybridization events is required.

keiru 7y ago

>mainline of the genetic stream This is a tricky concept. Could it be said over 50,000 years ago that Homo Sapiens' ancestors were the mainline? I wouldn't retroactively call it that because it presumes that it was clear at the time that it would be the definitive dominant subspecies. I think a better phrasing would be "genetic divergences, some of which were preserved by the cross-merging with the only surviving genetic stream", or something of the sort.