I once watched a documentary where it was mentioned that homo sapiens co-existend with around 20 archaic human forms (Homo erectus, Homo floresiensis ...etc) , of which only homo sapiens survived and thrived.
But this is a subject that always scared me especially with nowadays' politics.
During the period for which we have evidence, Neanderthals seem to have had smaller populations than Homo sapiens, and they reproduced more slowly (longer gestation plus longer interval between pregnancies). So it may be that they went extinct for those reasons.
Their ratio was about the same as homo sapiens. It's not clear that they were less intelligent, they seem to have had a similar degree of intelligence based on findings from caves in Spain.
If I were to hazard a guess, it would be that the species line is somewhat subjective. If you slide broader than today’s definition then we had a lot of human genocide in our collective past. If you slide narrower than today’s definition then we could end up with a lot of human genocide (by today’s definition) in our collective future. Anything to do with genocide is rather scary.
In the 50s, it was thought that we were smarter than them and killed them all off (the author of Lord of the Flies even wrote a book on this).
This seemed to inform futurists at the time thinking about what it would one day look like if there was something smarter than humans.
Hopefully we do a better job at considering this revision to our picture of the past and correcting our anchoring bias in our estimation of such a future.
It's not known for sure why they went extinct and the extent of their cognitive abilities. It's also only one example. Another might be Europeans coming to the Americas (with more deadly technology and infections diseases, not smarter). Or humans being super predators. We don't know what advanced alien life would be like. Or what AI might become. There's lots of possibilities. Sagan's Contact and The Culture are on on one end, with The Dark Forest and Skynet being on the other.
I wonder how much both the early 20th century and the current postmodern views on relations with the Neanderthals was influenced by the politics of the times. Back then people wanted justifications for colonialism and promoted social Darwinism; now we’re looking to promote multiculturalism and global trade. Both ways we’re projecting onto the prehistoric past what we want to see there.
Well we don’t know that they were smarter than us. The EQ (brain to body ratio) of homo sapiens is 0.019 and Neanderthals was 0.017. They were probably considerably stupider.
I saw a documentary on humans and Neanderthals about a decade ago and it melted my mind. Absolutely fascinating that there was another species that was very similar to us that we interbred with. Crazy!
I kind of feel the opposite: the crazy part isn’t that we had relatives, but that we’re the only remaining species of the Homo genus.
It’s somehow unsettling that we are the only ones left. Most large mammals come from a genus with many cousins. We’re alone either because we killed the others, or because intelligence actually has a hard time surviving in nature. Neither is really good news for us.
The taxonomy of archaic humans is debatable to say the least so "we are only the ones left" may just be an artifact of 19th century anthropology and prestige chasing. Realistically the genetic variation between the average human and Neanderthals is only about twice the variation within the modern human gene pool. Compared to our nearest primate at 10-50x the difference depending on how you measure.
Given the number of genetic bottlenecks we have evidence of in our past, we may all be the same species and the modern human is just the last surviving group of inbred Homos.
Not really - genetic bottlenecks aren't a feature of intelligent animals, it's a feature of a population that's undergone some kind of very dramatic pressure event like catastrophic loss of habitat or mass illness.
Bottlenecks are more likely to be an issue for species with a limited range, population and a slim range of survivable conditions. Intelligence has a way of expanding those ranges by making you more equipped to access otherwise inaccessible resources. Think of elephants navigating between watering holes during droughts, crows using tools to fish out hard to get food, or orcas using sophisticated hunting techniques to get at prey they otherwise could not.
Intelligence adds flexibility, and flexibility is especially useful under pressure.
which implies that there are humans alive that are genetically as far apart from each other as the average human was from the average neanderthal (i.e. statistically there probably exists humans who's separation from each other is twice the average distance).
> or because intelligence actually has a hard time surviving in nature.
Alas, I can't find it now... there was a book that I read (Bear / Brin / Benford as the author I believe... maybe Baxter... one of the great Bs I'm sure of) about the matrilineal line from a small shrew like animal in the time of the dinosaurs through neanderthals to modern times... and beyond.
Part of the "and beyond" was the theme that intelligence and our brain is an extremely expensive organ to maintain (our brain consumes about 20% of the calories that we consume a day https://www.ncbi.nlm.nih.gov/pmc/articles/PMC124895/ ). After some catastrophe that reduces the energy budget that animals can use... well, intelligence is one of the things to go.
I think that any forecasts are probably reading too much into a limited data set.
Intelligence does have an incredibly hard time surviving in nature. Humans are hyper-optimized for it. We are far weaker than chimps, and burn 30% more calories. We are slow reproducing k-strategists, with infants that are helpless for years.
That said, Humans are planet level apex predators, and universal omnivores that consume everything whales to yeast and synthetic foods made from elemental materials.
Over the course of our existence, our capability for growth has vastly overshadowed any downside from intra-species hostility. We are also the most cooperative and social animal that has ever existed.
This is a pretty strong position to be in, and certainly better than just about any other animal sharing the plant.
Or may be because we lived together for so long that individual differences disappeared and averaged out as people intermarried and had a lot of mixed babies.
I'm not saying that this necessarily happened, only that the burden of proof for your theory should be higher.
This is what happened, logically speaking. Though not averaged out in a balanced manner: instead, to the degree that Neanderthal genetics comprise anyone's genome.
Not to say that there weren't interspecies genocides, but we interbred with them and then outcompeted, for resources, the pure species into extinction generally speaking. Which was inevitable, parallel to how homo sapien lineages also die out from simply being outcompeted.
It is likely that the Neanderthal genome was outcompeted down to a percentage at which it was and is competitive. 50-50% Neanderthal-Modern Human? No dice, Darwin. It had to be reduced to a few percentage points, at which point individuals started being competitive. Was the last pure Neanderthal pair murdered, did they die from starvation, or did they just refuse to have kids? It could have been any of those, but the general procedure was likely defined by resource competition.
And Neanderthal isn't the only alien-homo genome mixed with that of modern humans.
Were Neanderthals more genetically different from typical Homo sapiens than modern day pygmy peoples? Iirc, Khosians also diverged genetically from other regional peoples.
It doesn't follow that if human males stole Neanderthal wives sometime in the past, that you would necessarily see Neanderthal mitochondrial DNA in present populations.
Consider a serial 'wife-stealing' human culture. One generation of human males leaps upon a small population of Neanderthals, killing the men and stealing the women. The next generation, a new group of half-neanderthal males leaves the colony in search of wives, finds a human group, kills the men, and steals the women. The children of this generation will be 1/4 Neanderthal with no Neanderthal mitochondrial DNA. Imagine that the first colony gets wiped out, as most ancient communities were. There you go.
It probably went both ways to some extent. But the Neanderthal population was much smaller, and probably martially weaker, as they were clearly playing a losing evolutionary strategy.
As far as we can tell Neanderthal populations were very small and fragile (very low genetic diversity) to begin with. So it’s not unlikely that modern human just absorbed them.
A bit like the hunter gatherers who pretty much disappeared in much of Europe during the Neolithic
The Americas were rich with diverse megafauna until homo sapiens arrived and, logic dictates, hunted them to extinction. Humans have outcompeted every species that has threatened us, gotten in our way, or happened to look delicious. Genocide word we use to describe efforts to extinct human subgroups. Why should we believe that prehistoric homo sapiens weren't at least party responsible for the extinction of other hominids?
I think they are very likely responsible. I just think genocide is defined by intent to exterminate. If we simply ate them all up and their extinction was incidental, I dont think that counts. Same if humans ate up all their food, or mated with all their female, or spread disease they were not immune to.
Means pretty much the definition: "the deliberate killing of a large number of people from a particular nation or ethnic group with the aim of destroying that nation or group."
So yeah...in my crazy conspiracy theory (which I don't take very seriously) I think Neanderthals may have been systematically hunted down and exterminated.
When you study human history you soon discover that no matter the era, we have a total fondness for killing each other.
Thats not what I said. Im just commenting on what what genocide is, and there is a component of knowledge and intent. Even your quoted definition has it.
I don’t see a way to read what you wrote other than condoning genocide. You are making excuses for when it is okay to make others go away. Argue that it’s not “genocide” - whatever - if the outcome is the same and you are saying it’s okay, you are condoning it.
another interesting fact is that modern Europeans are descended from 4 distinct populations which were as genetically distant from each other as modern Europeans are from Asians: Western hunter gatherers, anatolian farmers, eastern hunter gatherers, and eurasian steppe herders. David Reich goes into it in his book 'Who we are and why we got here'.
> another species that was very similar to us that we interbred with
Ok, if it is so similar to us and we interbred with it, then why is this so special? Might as well call it the same species by stretching the definition a little.
We were only "separate" species because for a period of tens of thousands of years we did not interbreed and developed independently due to physical separation. But we could and did interbreed when the physical separation was crossed. Despite the separation, we remained similar enough genetically that interbreeding was possible.
Were there a higher number of miscarriages than between 2 humans? We will probably never know.
That is one of the issues with species as a concept. There are quite a few differing definitions which are all useful. It’s typically discussed as the ‘species problem’.
Based on modern DNA patterns there also seems to have been at least one other major population group around the same time that we have not found any remains of, which was related to both Sapiens and Denisovans.
They probably lived mostly around southeast Asia. (Neanderthals were mostly in Europe and Denisovans are thought probably to have generally inhabited northern Asia).
I can highly recommend The World Before Us by Tom Higham, it goes into the history of the archaeology and science and also goes over a pretty up-to-date understanding of the topic of recent Hominin evolution.
(Also, it's very likely I've misconstrued some of it in my paragraphs above, apologies if so).
IMO it's not that there 'were' multiple species and only we survived; we are still multiple species, but we don't point that out for cultural correctness. Yes, the extent of our differences has narrowed as we passed through survival bottlenecks, but we never became a single species.
To be pedantic about the fuzziness of the "species" delineation, not every human is capable of producing viable, non-sterile offspring (breeding partner notwithstanding).
The fact that some individuals are sterile has nothing whatsoever to do with species delineation. If there were entire pairs of population groups, say the Ainu and the Xhosa, which can no longer produce viable offspring with each other due to generic distance, then we could begin a conversation about speciation of homo sapiens. But there aren't, so we don't.
Given that there is a single species of human today and most of us have some percentage of Neanderthal DNA, it seems that we are one species today and we were also one species in the past (since we could and did interbreed)
That is tautologically true, considering how Neanderthal is an offshoot of Sapiens.
The question maybe worth asking is just how far they split off, compared to how far we are split off today (or maybe in the pre-modern era, I would expect us to be merging fast since then).
This is complete bullshit. We've sequenced neanderthal DNA and can tell exactly how much modern people have in common.
If you want to promote some scientifically-accurate racism, the only "pure-blooded" homo sapiens come from central and southern Africa, everyone else is just a little bit neanderthal.
Right? Arthur Clarke has a story in which our long lost cousins finally come to rescue us from the shipwreck millennia ago, and offer also to correct the genetic mutation that reduces skin pigment...
But this is a subject that always scared me especially with nowadays' politics.