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Mysterious ‘super-archaic’ populations had multiple trysts with human ancestors

sciencemag.org

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Re: Mysterious ‘super-archaic’ populations had multiple trysts with human ancestors

#31

Post by ladberg »

Ygg2 wrote: post #28
jimktrains2 wrote: post #4

It's a running joke in Dr who, where as humanity spreads into the starts there eventually ceases to be any pure humans (and many other alien species) because humans will mate with anything. I think it's most interesting to think of how fluid what we mean by species really is. We've always known it was fluid, but I think many people never really consider that when thinking about ourselves.

Dr. Who is wrong. We could not mate with anything amongst the stars. Even if aliens exist they would be radically different. You might as well as bone your VCR. The act of separation would create new species. Not our drive to bone.

Doctor Who is also wrong about magic and time travel existing, but it's a fantasy show so it doesn't matter.

Re: Mysterious ‘super-archaic’ populations had multiple trysts with human ancestors

#32

Post by thaumasiotes »

Groxx wrote: post #22
thaumasiotes wrote: post #9

Earlier quoted context omitted.

> but for Homo sapiens that "other group" would be of a different species and we thus we shouldn't be able to produce fertile offspring with them. That's one definition of "species" (specifically, it's "the biological species concept"), but like all the other definitions, it doesn't work and does not correspond to most usage of the term. You can read modern genetic work discussing how homo sapiens interbred with homi…

It also wouldn't surprise me if "can reproduce with" isn't a transitive property (edit: actually, I'd be very surprised if it always is . genetic stuff is never that simple). So even if you try to collapse species into that strict definition, you'll still have edge cases that don't fit. Categories are hard.

> It also wouldn't surprise me if "can reproduce with" isn't a transitive property

"Can reproduce with" is not a transitive (or even a permanent!) property among individual humans. (For a more general transitivity allowing for the fact that it doesn't make sense to ask whether males can reproduce with males.)

Re: Mysterious ‘super-archaic’ populations had multiple trysts with human ancestors

#33

Post by interestica »

jimktrains2 wrote: post #4

It's a running joke in Dr who, where as humanity spreads into the starts there eventually ceases to be any pure humans (and many other alien species) because humans will mate with anything. I think it's most interesting to think of how fluid what we mean by species really is. We've always known it was fluid, but I think many people never really consider that when thinking about ourselves.

I always wondered if there could be some sort of in-world explanation as to why all the aliens in star trek/wars are so ...humanoid.

Re: Mysterious ‘super-archaic’ populations had multiple trysts with human ancestors

#34

Post by mrec »

rsynnott wrote: post #30
chmod775 wrote: post #5

Earlier quoted context omitted.

This sentence doesn't make any sense: "H. sapiens doesn’t have the possibility of quickly grabbing a load of diversity by mating with another group". It would make sense if she specifically referred to Homo sapiens sapiens, but for Homo sapiens that "other group" would be of a different species and we thus we shouldn't be able to produce fertile offspring with them. Also Homo sapiens sapiens have plenty of genetic di…

> Also Homo sapiens sapiens have plenty of genetic diversity. Humans aren’t particularly genetically diverse, given our dispersal, though as far as I know there’s some disagreement on _why_.

I'd have assumed that it's largely because humans can spread to new niches via cultural evolution, which happens vastly faster than the old-fashioned biological kind. Much quicker to make a fur coat than evolve one.

Re: Mysterious ‘super-archaic’ populations had multiple trysts with human ancestors

#35

Post by gen220 »

adenozine wrote: post #2

Man, I've always actually kinda wondered about this. I know it's macabre, but I think about human migratory routines and when different groups clashed back when life was so primitive and brutish, they're must've been those tendencies to rape and sexually conquer the opposition. Surely that is reflected in the genetic ledger of time. What a crazy insight. Genetics is such an interesting field. It's bonkers there's jus…

I encourage you to explore the early history of the pre-Roman Empire peoples. These were largely mythologies that the romans retroactively constructed for themselves (i.e. they had the opportunity to omit the raping and kidnapping in retellings, but chose not to).

It’s full of “and then tribe X invaded and the land of Y, took their women and enslaved their men”. Back and forth for centuries. This behavior was cyclical, inevitable, and universal, until violence was monopolized and institutionalized.

We’ve come a long way, I guess. Still have work to do.

Re: Mysterious ‘super-archaic’ populations had multiple trysts with human ancestors

#36

Post by wincy »

interestica wrote: post #33
jimktrains2 wrote: post #4

It's a running joke in Dr who, where as humanity spreads into the starts there eventually ceases to be any pure humans (and many other alien species) because humans will mate with anything. I think it's most interesting to think of how fluid what we mean by species really is. We've always known it was fluid, but I think many people never really consider that when thinking about ourselves.

I always wondered if there could be some sort of in-world explanation as to why all the aliens in star trek/wars are so ...humanoid.

I think it’s that all the worlds were seeded by some sort of progenitor race millions of years ago. Also they can interbreed I believe.

Re: Mysterious ‘super-archaic’ populations had multiple trysts with human ancestors

#37

Post by thaumasiotes »

scarmig wrote: post #24
bigbubba wrote: post #23

Earlier quoted context omitted.

You're right, it isn't necessarily transitive. So called 'ring species' are cases where it isn't.

You don't even have to go as exotic as ring species. Climb up the evolutionary tree through each of your ancestors to some slime creature a billion years ago, and then climb down to your pet dog. Each connected node in that step can interbreed, but you can't mate with Fido. I guess it's kind of a temporal ring species.

Ring species are so called because their breeding relationships form a cycle. You're only describing a chain. You would have described a ring species if you could mate with your dog.

(Also note that while it's perfectly possible to walk up from humans to an ancestral slime creature, and then back down to dogs, most of the steps along that path will be shared between humans and dogs, like a Y with a very, very long leg. The recent common ancestor of humans and dogs would have already been a mammal.)

Re: Mysterious ‘super-archaic’ populations had multiple trysts with human ancestors

#38

Post by virmundi »

dragonwriter wrote: post #16
holoduke wrote: post #14

Earlier quoted context omitted.

Covid is comparable to flu with a higher mortality rate. Don't make it bigger than it is. 99.95% of the people are doing perfectly fine. Genetics are thus pretty effective

> Covid is comparable to flu with a higher mortality rate. So, like 1918 pandemic flu?

There is also evidence that the Spanish Flu was made worse by a magic new drug of the time: aspirin. Sadly we dosed people far beyond safe. We made them internally bleed to death. https://www.sciencedaily.com/releases/2009/10/091002132346.h...

By the way, here's evidence that the Spanish Flu had a 20% death rate: https://www.smithsonianmag.com/history/ten-myths-about-1918-...

Re: Mysterious ‘super-archaic’ populations had multiple trysts with human ancestors

#39

Post by Izkata »

wincy wrote: post #36
interestica wrote: post #33

Earlier quoted context omitted.

I always wondered if there could be some sort of in-world explanation as to why all the aliens in star trek/wars are so ...humanoid.

I think it’s that all the worlds were seeded by some sort of progenitor race millions of years ago. Also they can interbreed I believe.

For Star Trek, in-universe this happened at least twice. The relevant episodes are TOS 2x22 Return to Tomorrow [0] and TNG 6x20 The Chase [1].

VOY 3x23 Distant Origin [2] also in-universe establishes convergent evolution is very likely to create humanoids (makes no reference to the other two episodes, as far as I remember, but it's kinda wishy-washy in that it could be highly likely because of the two progenitor species).

That said, there's plenty of non-humanoid aliens. Off the top of my head: Q, the Tholians, the Caretaker's species, the two aliens from TOS 2x01 Catspaw (shown to be tiny and kinda birdlike in the final scenes), and Species 8472.

[0] https://memory-alpha.fandom.com/wiki/Return_to_Tomorrow_(epi...

[1] https://memory-alpha.fandom.com/wiki/The_Chase_(episode)

[2] https://memory-alpha.fandom.com/wiki/Distant_Origin_(episode...

Re: Mysterious ‘super-archaic’ populations had multiple trysts with human ancestors

#40

Post by tzs »

> The story of human evolution is full of ancient trysts. Genes from fossils have shown that the ancestors of many living people mated with Neanderthals and with Denisovans, a mysterious group of extinct humans who lived in Asia

In the case of Neanderthals, isn't that "all" people rather than "many" people?

Neanderthals are believed to have gone extinct 40000 years ago.

But there was an article here the other day about the genetic isopoint [1], which is the most recent time when every human alive then was either an ancestor of every human currently alive or had no descendants that are currently alive.

Most researchers put the genetic isopoint somewhere between about 4000-15000 years ago.

If both of these are true (or even if not, as long as the genetic isopoint is after Neanderthal extinction), then all my ancestors that descended from Neanderthals and were alive at the genetic isopoint are also your ancestors, and so you are also descended from Neanderthals through them.

There seems to be a lot more uncertainty about when the Denisovans went extinct. It seems likely that they were probably also all gone by the isopoint and so "all" rather than "many" probably goes for them too.

[1] https://news.ycombinator.com/item?id=24686904

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