I was listening to a podcast yesterday and they were mentioning that there is no hardline consensus on why the other proto-humans (if that’s the right term) died out. Lots of theories and speculation, but I don’t think we know for sure what killed off each group. According to this podcast’s perspective, some groups were well equipped to last longer than they did.
Some of the other contemporaneous human species include:
My question is, do you think it was inevitable that only one group would survive? Can you imagine a world where we coexisted with another group like the Neanderthals (in business suits!)? It appears they had the capacity for speech which couldn’t have hurt.
I also wonder if we had lost out to another group, if they would have eventually developed higher technology (electricity, cars, planes, space travel?) And if so, what group showed the most promise for those?
Exactly what I was going to post. Though I suppose there are still scenarios where multiple survive, if all of the expansionist species died off, leaving only two or more isolated species who stayed on their own islands, and therefore weren’t directly competing.
I think it would be possible if the two groups were isolated from each other until modern-ish times, in say the Americas vs AfroEurasia. But that would have involved changes to both migration patterns and geography to happen.
To what degree are we absolutely bound by the laws and principles that bind plants and animals? To what degree has our existence been marked by scarcity? Those questions may help us think through the OP
Or if one of the other Hominids had somehow made it to a remote island area that was not discovered by Homo Sapiens until quite recently (New Zealand e.g.) then the hominids might have survived up to today.
Once a species has a superpower, the normal rules of natural selection are suspended. Sapiens has a superpower, possibly many depending on your definitions and criteria. Intelligence leading to toolmaking, language, and dominion over land and other animals is sapiens superpower. Sapiens can destroy itself or an external event like a planet-destroying meteor could do the job, but no other species however closely related can compete. The superpowers of sapiens do not seem to have been apparent in the oldest examples of the species; when and which developments led to them is debated. Regardless, it happened at some point no later than the extinction of neanderthal. (Not floresiensis, which had no chance.)
I think if they are Homo, they aren’t proto-humans, just humans.
I think it’s pretty unlikely that two intelligent, tool using species of Homo could coexist in the same place. When species do that, they tend to niche partition, and I just can’t imagine Homo species doing that. We are too flexible and adaptable; we make tools and change the environment to suit us.
But if the timing had worked out slightly differently, it’s not difficult to imagine a world where Denisovans or a similar species makes it across the Bering Land Bridge first and establishes itself in the New World, with sapiens arriving on the scene only after the land bridge was submerged. Harry Turtledove wrote a book called A Different Flesh based on this premise, but it is one I haven’t read yet.
On the other hand, there were animals that were closer to humans than chimps, but which were not very intelligent nor tool using. Creatures like Paranthropus were hominids but instead of developing bigger and bigger brains they became grazers, developing large and robust teeth and jaws with which to grind down tough plant matter. One could imagine a hominid, even one that’s even more closely related to humans, that develops down a similar path; I don’t see why we couldn’t coexist with such creatures, any more than gorillas or chimps.
If they were advanced and numerous enough before our type of humanity encountered them, yes. They weren’t killed off by some systematic effort; there flat-out wasn’t enough organization back in the Neolithic for that to be possible. They were just in competition for the same ecological niche and lost.
Civilizations can be genocidal of course, but they are also organized enough to be able to decide not to be genocidal. History is full of civilizations that meet other weaker cultures and don’t bother to exterminate them. How some culture in the Bronze or Iron Age would respond to meeting a near-human culture would depend a lot on how advanced and numerous they were, not to mention on how their and our diseases interacted with our respective populations. If the Native Americans had been near-human species that didn’t suffer an apocalyptic death rate from European diseases, it’s unlikely the same outright genocide of them would happen; and if their diseases near-destroyed Europe instead, the colonization might have gone the other direction.
“Behavioral shift toward a different ecological niche” is certainly an alternative to extinction, however. We even saw the non-biological version of that in real life, with the agriculturalists outcompeting the hunter-gatherers; the HGs ended up occupying the regions less suited for agriculture, but they still existed.
Some hominid species that liked living in a place or way unappealing to us might well have survived. For example, a hominid species adapted for desert living that needs less water might hang on in arid regions both because they can sustain a larger population with less water, and because deserts are typically regarded as less appealing to our kind of human. A cold-adapted hominid species might have managed to hang on just because General Winter is on their side.
Well, yes, animals in the strictest sense but I would say we have the capacity for empathy and emotional concern for others that, say, lions lack. And it’s true that other animals can show these traits but true human-level compassion—which requires complex cognitive perspective-taking—differs in scope and depth from these other animals.
This would apply if it has been conclusively shown that this was the reason Neanderthals died out. I don’t think it has, or at least that’s what I’ve read. Playing devil’s advocate, there are some in the scientific community that don’t subscribe to this. Genetic evidence proves that Homo sapiens and Neanderthals interbred, meaning they were not strictly isolated competitors under a purely (ecological) exclusionary model. And Some researchers argue that rapid climate fluctuations or that demographic vulnerabilities (such as small, isolated Neanderthal population sizes) played a larger role than direct competition alone.
For other humans in our ingroup, sure. The abstract idea of extending that all the way to worrying about wild animals going extinct is very recent, though.
I think you’ve shown that for the the majority of the existence of Homo Sapiens, we’ve not been the only members of the genus Homo around, so our current status seems like an aberration. The rule of competitive exclusion doesn’t mean that only one species of a particular genus will survive - there are many genuses that have multiple species around at the same time, specializing to particular areas or strategies (see Canis).
That being said, we’re an expansionist species, so competition might have led to extinction of all but one Homo species, but we can’t neglect the possibility of pure bad luck - the other Homo species might have gotten bad breaks that had nothing to do with us.
For fictional examples, by the way, Harry Turtledove wrote a series of stories in which a variant of Homo Erectus remained in the New World (and Homo Sapiens didn’t arrive their until modern time) and also wrote a story (Down in the Bottomlands) in which Homo Sapiens and Neanderthal were separated by a dry Mediterranean which allowed both to thrive separately until modern times. And of course Larry Niven has hundreds of Homo variants on the Ringworld for reasons that are spoilers.
The interbreeding between modern humans and Neanderthals is high enough that it has been proposed that it should be Homo sapiens neanderthalensis, i.e. that they are a subspecies, and we are more properly Homo sapiens sapiens.
Is there any indication of interbreeding among other species of human?
And at least two other “ghost lineages” we know even less about.
Now, researchers have developed a new method to analyze modern human genomes and uncovered evidence of two previously unknown ancestral lineages by working backward from DNA in living people to reconstruct missing parts of the human family tree. One of the lineages appears to have interbred directly with Homo sapiens in Africa more than 50,000 years ago, while the other was an even older group that passed some of its DNA to humans indirectly through Denisovans.
We really don’t know enough about Denisovans to understand how well a large population would withstand competition with a large population of Sapiens. Extrapolation has to be fanciful.
The Neanderthal case is better understood, albeit still mostly iffy. My reading does agree with yours, in that sheer head-to-head competition did not make Sapiens the winner, but that Neanderthal just couldn’t overcome a combination of obstacles whereas Sapiens did.
Being better at that is the core of natural selection. Hard not to consider that as one species out-competing the other over a non-isolated area. The other Homo species seem to have been geographically limited over the same time periods that Sapiens was spreading throughout the globe and creating and adapting tools and language and probably also social structures to master the variety of obstacles.
Extrapolation from a single data point is a non-winnable game. (See: does life exist on other planets.) What evidence we have, though, is that Sapiens’ advantages let them survive, out-compete, and - possibly - drive into extinction other Homo species at the very beginning of a hockey stick rise steeper than global warming.