Ask Lemmy

hideshow 9 child comments

parent

[–] workerONE@lemmy.world 9 points 3 weeks ago* (last edited 3 weeks ago)

Now they're pretty sure that people used boats and skirted the coastline but didn't walk.

This is a great video about human migration to the Americas https://youtu.be/UsnrdCdGs7o

parent

[–] AbouBenAdhem@lemmy.world 7 points 3 weeks ago (6 children)

That article's over 20 years old—I'm not up on the latest findings, but I know there's been major work since then on both the peopling of the Americas and on the importance of genetic diversity.

hideshow 6 child comments

parent

[–] Blue_Morpho@lemmy.world 7 points 3 weeks ago (4 children)

It's the other way around. It was once believed that a population of hundreds were needed but the DNA evidence proved it to be much smaller. If you have newer information that shows the DNA work done was wrong, please post it because I've been pulling out this trivia for years.

https://en.wikipedia.org/wiki/Genetic_history_of_the_Indigenous_peoples_of_the_Americas

hideshow 4 child comments

parent

[–] Vandals_handle@lemmy.world 4 points 3 weeks ago

Don't know about the DNA but White Sands Footprints were dated over 20,000 years old, someone arrived before land bridge was available.

General rule in wildlife biology 50/500. Need 50 individuals to prevent extinction, 500 to have potential to evolve/survive threats.

Here are a couple papers that say those numbers are too low but I don't have access to free copies. Second one a little beyond my understanding.

https://www.sciencedirect.com/science/article/abs/pii/S0006320713004576?via=ihub

https://www.sciencedirect.com/science/article/abs/pii/S0006320706002126?via=ihub

https://en.wikipedia.org/wiki/Peopling_of_the_Americas

parent

[–] AbouBenAdhem@lemmy.world 3 points 3 weeks ago (2 children)

Hmm... the only cited sources in that article for a specific (effective) population size are also over 20 years old—the more recent sources just say it was likely a “small” number.

This article has a lot more detail on the various migration theories, but refrains from any specific size estimates:

hideshow 2 child comments

parent

[–] Blue_Morpho@lemmy.world 4 points 3 weeks ago (1 child)

the only cited sources in that article for a specific (effective) population size are also over 20 years

When research is old without being found wrong, it is more likely to be correct.

parent

hideshow 1 child comment

[–] Vandals_handle@lemmy.world 2 points 3 weeks ago

Lots of truth to that but not a lot of grant money available for replication research. After initial peer review might not get revisited for a long time.

parent

[–] Rhaedas@fedia.io 5 points 3 weeks ago

Along with other bottlenecks once thought to be humans on the brink of extinction, like with the Toba eruption, further research tends to find other evidence to reverse the extreme nature speculated on. We do on the other hand have evidence of other species that had bottlenecks caused from disasters and the genetic signs are very obvious. Cheetahs as an example.

parent

[–] Modern_medicine_isnt@lemmy.world 1 point 3 weeks ago

As few as... likely meant anywhere from 70 to 7000. The ranges on such predictions are usually very wide. Also, sure, 70 people could get lucky and not get wiped out. But the odds are strongly against them.