Denisovians Survived on Tibetan Plateau for 160k Years | Hacker News Reader

Denisovians Survived on Tibetan Plateau for 160k Years

explorersweb.com

35 pointsjamesblonde9 comments

Reading stories about ancient hominins always piques my imagination. The incredible spans of time, the various species and subspecies (of which at least some were apparently interbreeding), and the lack of historical record always leave me wondering what endless stories have been lost to the annals of time.

And how (and why) did they manage to populate so much of the planet so long ago without any technology. What made them venture out more and more over thousands of years to end up in the Americas, Asia, Oceania, etc. On foot!

Chris Hasler is the wonderful person that made https://historyoftheworldpodcast.com which is a great resource for anyone interested in the topic. Especially the early episodes in Volume 1.

> The recently discovered bones include one Denisovan rib that dated to between 48,000 and 32,000 years ago. This is the same time that Homo sapiens were spreading across Eurasia. We already have evidence that these ancient humans lived in this area 190,000 years ago. The new fossil suggests they endured two cold periods and a warmer interglacial period between the Middle and Late Pleistocene eras.

So without mentioning what the evidence is about 190K years ago, from two points we infer that they were there the whole intervening time? If conditions were harsh, and if we know they eventually got at least as far as SE Asia, why would we not think that in the huge span between those points, they might have wandered away and later returned? 160k years is a long long time. Apparently humans came across the land bridge into the Americas like 16k years ago.

The interesting thing is that apparently there were still unassimilated Denisovans in Eurasia 48,000 years ago.

> from two points we infer that they were there the whole intervening time?

This is not deductive, it's abductive. The reasoning is weak but it's all the reasoning paleoarchaeology offers.

TBF this is basically all science but we kind of smear the probability aspect and call it scientific fact.

How do we know a piece of rib is from a Denisovan? Is it just based on the age of the find?

DNA in bones, in ideal conditions, will completely disappear after ~6.7 million years. Researchers have successfully recovered dna fragments from a 2 million year old mastodon, for instance.

There are numerous ways to identify the origin of ancient remains. FTA about the non-Denisovan remains:

>Unfortunately, the bones were in such small fragments that they were nearly impossible to identify by sight. Instead, the researchers analyzed the bone collagen using mass spectrometry to figure out what species they belonged to.

DNA

Reply on news.ycombinator.com