No doubt there are many, many other varieties of humans which we'll never know about because we'll never find any bones.
What chilling is that shows very clearly that humans can go extinct. In fact, humans go extinct all the time: 50,000 years ago, we shared the earth with at least 5 different varieties of humans (Homo Neanterthalensis, Homo Denisova, Homo Naledi, Homo Florensiensis, and Homo Luzenenensis). Probably also some late surviving populations of Homo Erectus and Homo Rudolfensis. Almost certainly more we'll never know about.
Since the last ice age we've been dropping like flies. In fact, we're the only humans left. And what with climate change, accidental nuclear war, or the singularity looming, we are arguably in a more precarious position than we've ever been.
No amount of climate change short of Venusian runaway heating will scour the earth of humans.
If we launch all of our nukes, we might collapse civilization, but even that would likely leave humans around. We might get stuck in our gravity well for a long time, though.
Whatever makes us go extinct will either be cosmic or something we haven't invented yet.
We cool our bodies by sweating, a process which ceases to work at about 95 degrees at 100% humidity, or 115 degrees at 50% humidity. Its been estimated that an average temperature of above 122 degrees F would kill off all mammalian life on the planet.
Currently the earth is warming at about 1/3rd of a degree F per decade.
Seeing how the summer mean daily maximum in my city is 95.8 deg F and the mean humidity averages 80%, I think we already cross your threshold frequently. It hasn't killed us yet. I would frequently go running in the afternoon during "heat stroke" days. I love that weather. Hot and humid summers are personally invigorating. I grew up with them. I'd like to see your sources.
> Currently the earth is warming at about 1/3rd of a degree F per decade.
Every decade our technological capability increases dramatically. We're already working on climate engineering. Nothing here will extinct us.
See the July 19, 2022 Issue of the Scientific American, "How Hot Is Too Hot for the Human Body?"
// I would frequently go running //
Recall, it's 95 degrees at 100% humidity. The more humid the air, the less sweat will evaporate. I don't care if you are Jesus Christ Usane Bolt Superstar, above 95 degrees at 100% humidity, if you run long enough you will get heatstroke.
// Nothing here will extinct us //
Extinction has happened to every other species of Homo. Every. single. one. I wonder how many of them accurately predicted when and why they would go extinct....
I spent fifteen minutes in a 112 deg F shower today [1] at presumably near total humidity. I do this all the time, and that isn't even hot.
I was born and live in heat, so when I hear cold climate SF denizens say the end is nigh, I have to chuckle.
I took a look at your source [2]. I'll have to read the underlying literature. The way this is presented to a lay audience doesn't make it clear if they're controlling for acclimation. I'm not educated in physiology beyond an undergrad class, so I'm not sure if their measure is a good proxy.
It'll take sixty years to raise the temperature two degrees, after which I'll probably be dead. It'll take centuries to push into dangerous ranges. I think we're already building the tech to deal with this, and very little growth is exponential. This is going to be yet another sigmoid. And in geologic times, just noise.
I will say I am worried about loss of species diversity. But I'm more worried about a lack of cheap energy to fuel our ascendent climb to the next stages. And more worried about nukes.
As far as green tech goes, I've always been worried about particulate matter in the air leading to cardiopulmonary diseases. So it's not a bad thing and I've never once been against it.
What I am concerned about is that we're teaching Gen Z and Gen Alpha to just give up. Go look at /r/GenZ and all the threads about climate - these kids are just giving up on life because of these memes. In reality, their lives will not be impacted by climate change whatsoever. We're scaring them to death and their entire generation is experiencing trauma because of this.
We do need to control these systems, and we do need to protect ecosystem biodiversity, but this hysteria is ridiculous.
// I spent fifteen minutes in a 112 deg F shower...I spent fifteen minutes in a 112 deg F shower //
Did you measure your body temperature? Were you able to cool yourself by sweating, or was your body temperature monotonically rising?
Recall, it is recommended that you go to a doctor if you have a fever of over 103 degrees, and over 108 degrees you risk brain damage.
Soaking some nice heat into your sore muscles in a 20-minute shower is one thing; but 24/7 your body is absolutely, positively not able to cool itself down is quite another.
// They don't control for so many things, let alone acclimation. //
Hey man, I gave you a source as requested. Whether or not evaporating water can cool down a body of a certain volume and surface when that body is internally generating heat--that isn't a matter of acclimation, its a matter of thermodynamics.
// after which I'll probably be dead // And why think about extinction after I'm dead, eh? :-) But far before 60 years passes, you'll find yourself in the age demographic for which death from hot weather is a risk. The body's ability to thermoregulate degrades as we get older, alas...
// worried about a lack of cheap energy //
Wind farms are already cheaper to build than coal-fired plants. And if you factor in all the externalities, fossils fuels don't even come close to being a cheap source of energy.
// we're teaching Gen Z and Gen Alpha to just give up... this hysteria is ridiculous //
Worrying about how the media affects "kids these days" is a normal, expected part of the aging process :-) ....maybe, perhaps, the thought that Gen-Z and Gen-X are just giving up is a bit, well, I won't say hysterical, but perhaps a bit hyperbolic? And inasmuch as they are going to be here longer than we are, they do have a bit more of a stake in the future than we do.
I assumed the original poster was talking about extant wars, not threats. This doesn’t even rate compared to say the Cuban missile crisis or even just the normal state of the world in the ‘80s.
You're being downvoted for several reasons, and I find them all maddening and infuriating.
First, you've got those folks who are in deep denial about how much we've utterly fucked our climate, i.e. "don't look up, just vote down!" Included in this group are those who think/feel "things got better over the past 100 years, so the next 100 years must be better too!"
Then you've got the astroturfers who are paid to minimize any discussion of climate disaster for whatever reason; governments, political movements, oil companies, etc. I see those in comments on the larger newspapers, they swarm in and state contradictory "facts" that confuse people and shut down discussion.
Personally, after the experience of COVID-19, the inability of governments to give up the easy money from oil etc, and the lack of reaction to extreme weather events, I think humanity is utterly doomed. If anyone survives, I don't think there will be more than a couple million people left at the end of this century.
People talk about "oh we'll just do X, Y, and Z to fix things" while forgetting that we'll have to do those things while dealing with:
Dude its called air conditioning, and we can grow the world economy to put it in every hut in africa within the decade if people are free, its impossible to "reverse" the effects havent you heard?
I can't make much sense of your comment. It sounds like you're proposing that we air condition anywhere affected by warming. What about farmer's fields? Oceans? Do you know how many people work outside to keep you in air conditioned comfort?
Even if that were possible, humanity has shown that we will only do something worldwide when we're absolutely forced to. We will not be able to do that while dealing with the disasters that come with global climate catastrophe and ecological collapse.
// we can grow the world economy to put it in every hut in africa within the decade //
A refresher in thermodynamics is in order here....thermal energy is...energy, which is a conserved quantity. Heat doesn't just disappear. An air conditioner cools the inside air by making the outside air hotter.
And (thermodynamics strikes again) it also creates yet more waste heat in the process.
// if people are free //
Doesn't matter how free people or the markets are, thermodynamics is for real. We are not air-conditioning our way out of this.
Your comment would carry more weight if human population wasn't increasing each year.
The best counterargument to the population trend argument is that we're in the midst of a Wile E. Coyote period. Along with that though one still needs to account for:
- What's different about weapons today versus say 1970s?
- Why climate change, despite being a serious (and to be clear: actual risk), isn't amenable to solutions like the Montreal protocol that've succeeded in the past?
I have absolutely no idea what you mean by "Wylie E Coyote period", can you explain? I did DDG it but couldn't find much. Without that I'm unsure I can properly comment why I need to account for your other points.
But sure the Montreal protocol and even the response to COVID 19 shows what can be accomplished should everyone work together. But it wasn't too late in either case then, and they were easier to solve. Today's weapons are definitely scarier than 1970s weapons.
Either way, I wasn't attempting a definitive list with my two items and "etc", I'd consider overpopulation as big a threat as climate change, the fact it's increasing each year is part of the problem.
> I have absolutely no idea what you mean by "Wylie E Coyote period", can you explain?
The sibling reply expressed this as well. Wile E. runs off a cliff, the forward momentum keeps gravity in check but only for a short time.
The fact that human population continues to grow isn't by itself sufficient evidence that there are no existing parallel, possibly embryonic, trends developing that'll change that later. The period where both of these are true would be similar to when Wile E. is no longer on solid ground and hasn't yet fallen. It's a temporary and (on a relative basis, which could exceed human lifespan for sufficiently complex or slowly moving trends) brief period.
To be clear, I don't think it's an accurate view of where we are today. On the other hand, had the changes we've seen since 1970s not come to pass, it'd be harder to say. (An example that is climate change specific is the exponentially decreasing cost curve for solar energy.)
> Either way, I wasn't attempting a definitive list with my two items and "etc"
So long as the focus is on the definitive then IMHO there is value in looking hard here. Otherwise, why bother?
> Today's weapons are definitely scarier than 1970s weapons.
Open pit mines seem to be a pretty good candidates for this. They're pretty much the opposite of a structure, but I can't imagine them looking "natural" even thousands of years from now. I can imagine one or two getting overgrown, but ones in desert areas like Utah could last until the next deep ice age.
Can we? I'm not under the impression that those were ever terraced[1] like open-pit mines. But come to think of it, terracing itself qualifies as a megastructure[2]. Where the Long Now clock is an offbeat art project, rice paddies are crucial for nutrition for a great many people and they've already been around for at least 2 millenia. As times get lean, I can imagine pilfering the Long Now clock for parts; but those rice paddies will only gain importance.
Terraced open pit mines and rice paddies require an enormous amount of maintenance. The terraces are not naturally stable. Rice paddies will quickly silt-up, then flood and collapse in heavy rain.
Open pit mines will fill with water. The sides will collapse. In the desert, they will fill with dust. Deserts often have flash-floods following thunderstorms. They might remain recognizable as hollows, but not much more.
The Bingham mine has had collapses in 2013 and 2021:
This. It would take something truly catastrophic to make humans extinct now that there are so many of us on every part of the globe.
Climate change won't cut it, neither would total nuclear war.
Even if you had something like an impact big enough to superheat the entire atmosphere, enough humans might survive inside buildings, basements, subways, etc to carry on.
Modern civilization though is a lot more fragile. It's possible to blast us back to pre-industrial times and the easy to access resources are mostly gone. It's not clear that we could bootstrap a second industrial revolution easily.
Global thermonuclear war would destroy technological civilization, but even now there are small groups of pastoralists and hunter-gatherers in remote regions who use only muscle power and do not need factory manufactured goods. Uncontacted tribes [1] would go on living much as usual if a nuclear war depopulated industrialized regions.
There would be some increase in mortality among remote tribes as radioactive fallout from a large scale nuclear war drifted down globally, but that wouldn't be enough to cause human extinction.
> but even now there are small groups of pastoralists and hunter-gatherers in remote regions who use only muscle power and do not need factory manufactured goods.
Good luck getting them to adopt your useless ass in the post-apocalypse.
Large parts of the world would be untouched (Africa, South America, Middle East). You might get a nuclear winter, but many people would still survive that.
OTOH our garbage and wreckage will provide a lot of resources. For example there may not be any easily accessible copper deposits, but there are a lot of wires to scavenge. No easily accessible fossil fuels, but the amount of plastic in garbage dumps makes them a fossil fuel source.
To be clear I don't think anthropogenic climate change will cause human extinction. But a terrible series of volcanos could absolutely turn Earth into a colder Venus for, say, a couple hundred years - pelagic vertebrates and certain microbes would be ok, but I am not sure humanity would survive more than a few generations, even in underground sci-fi bunkers.
> It's not clear the Earth can even do that anymore.
This is a good point, but the event wouldn't need to be more volcanic so much as that volcanism would need to ignite more carbon-containing materials - naively I would expect there to me more "fuel" in the Earth than there was 300m years ago.
> But a terrible series of volcanos could absolutely turn Earth into a colder Venus for, say, a couple hundred years
Minoans went from the thriving trading center of the Mediterranean with written language as old as Egyptian Hieroglyphics to seemingly irrelevant for a while during the Bronze Age because volcanic eruptions seemed to have turned the air they breathed to poison. Not to mention places allegedly hit by the fall of volcanic ash whose remains are so far deep we only speculate they lived there.
With the proper breeding techniques and a ratio of say, ten females to each male, I would guess that they could then work their way back to the present gross national product within say, twenty years.
Regrettably, yes. But it is, you know, a sacrifice required for the future of the human race. I hasten to add that since each man will be required to do prodigious... service along these lines, the women will have to be selected for their sexual characteristics which will have to be of a highly stimulating nature.
Because the men have almost all killed one another off, leaving mostly those who managed to stay out of the fight? Who is supposed to teach the kids skills to rebuild civilization if who's left are wholly occupied with reproducing? Will you kill the infant boys too?
This is like a rejected version of one of Heinlein’s omni-competent hero fantasies. Humans aren’t fruit flies, with anll individuals interchangeable and ready for life shortly after birth. Even ignoring the dubious math getting to those numbers, think about the skills and equipment. In your scenario, everyone’s so busy taking care of food and childcare that they’re not going to have time to realize that they don’t have teachers for all of the subjects or specialists who can maintain intricate manufacturing lines. The people who work on semiconductors can’t just switch to make pharmaceuticals or engines!
Also the population for many of these earlier humans was much much lower. It's hard to give accurate population counts for many of these earlier humans – we don't know all that much about Denisovans – but for Neanderthals the total population was in the tens of thousands.
Our ancestors may have almost gone extinct 900M years ago. Some researchers looking at genetic data believe we were down to 1280 individuals [1].
Those were pre-human ancestors, but humans aren't special, we are just animals that are more destructive than any species that came before us.
Hubris will likely play a large role in any possible future human extinction event.
E.g., doing nothing to curb climate change because we are "smart" and invincible and/or god(s) wouldn't allow things to get that bad, a deadly pathogen develops resistance to all antibiotics because of free-feeding antibiotics in factory farming animal flesh, we use nuclear weapons in conflict X believing it will not escalate (George "Baby" Bush, "I want nuclear weapons I can use" [actual quote]), a pathogen intentionally developed to both spread quickly and be extremely deadly (because we can), that somehow... "no one could ever foresee the possibility..." escaped the lab-- or maybe it will be a large meteor impact wiping out humans (and other large animals) across the globe like a kid stomping on an ant hill.
Genetic data is misleading; it only means that number of people had surviving descendants. It's entirely possible that the population never dropped below N, but one particular tribe gradually became dominant and genocided everyone else. Remember that endogamy is the default!
it's possible to have a more positive take on this - those species did not go entirely extinct, as their genes continue live on within many of us - and thus we carry their legacy as much as we do for homo sapien. We might even speciate again one day, should genetic populations isolate again for a time
That's what I understood as well. In a way, they live on with us because they are part of the same species. We know that we have bred with Neanderthals. Why aren't they just considered a branch of humanity? It's normal for some designs to die out in favour of others. Slightly stocky humans with bigger brains. If you met one, I wonder what you'd think in comparison with, say, a person from another culture?
this is actually an active argument for the reclassification of neanderthals either directly within homo sapiens, or for a new grouping to created to cover all of these hominids. We have to remember that all taxonomies are flawed, useful simplifications layered onto top of a much more complext biological continuum.
>Since the last ice age we've been dropping like flies. In fact, we're the only humans left.
I was under the impression that was our doing. All of these human varieties were outcompeted by homo sapiens who replaced them. Modern humans don't need to worry about another hominid taking their place because we're the last one standing.
It's one possible theory, and no doubt, at the very least, it was part of the reason they died. But that's not the only smoking gun.
E.g. For at least 200k years, we can tell by fossils from the middle east that we made many attempts to spread to Europe, but were always pushed back. Fun fact: Neanderthals actually had substantially bigger brains that we do today (their average size was about 1400-1500ccs. Subtract the volume of a tennis ball from that and you'll get the average size of our brains today). Neanderthals were smart, tough, mofos.
So what changed 50k years ago which finally let us succeed? Well, the climate was warming from the last ice age, and Neanderthals were very much cold-adapted hominids. Their short, stocky legs and heavy muscular arms were great at sneaking through the woods and stabbing a deer with a spear, but when the climate changed the woods disappeared, those short legs, hauling a very heavy upper-body musculature, were not so good at running the deer down on a plain.
Honestly, we have no real definitive answer to why we are here and they aren't. Like anything else, probably it was a complicated process in which lots of factors--including dumb luck--played a role.
For about 4 million years, the earth was very hospitable to all kinds of species of Homo--we find their bones, in a kaleidoscope of shapes and sizes, all over the old world. Since the last ice age, however, Homo has been having a really rough time of it. And we are the only humans left.
If you were locked in a room with 10 people, and one by one they started to disappear, when you were the only one left, you might wonder whether it would happen to you too.....
The fact, that I am sitting here slacking off, reading something some dude wrote on the other side of the world just because he had nothing better to do and wanted to enjoy and share his own thoughts, takes away the fear of imminent extinction of my species.
Fun to think about. Maybe they were bigger and stronger, which forced us to actually be more clever and start to use our smaller but still very capable brains to accomplish stuff. I don't know if there were actually interactions between the different species, but I sure wouldn't want to fight a neanderthal without a plan or some tools.
I mentioned this in an HN comment earlier this week - be careful about the "Neanderthals had bigger brains than us" stuff. A big chunk of that difference is in the occipital lobe, which is involved in visual processing. And the likely reason for that is that they had significantly larger eyes than modern humans: Larger eyes = more pixels = more real-time visual processing demands (assuming Neanderthals had the same visual acuity as modern humans) = bigger chunk of brain, since evolution is not gonna easily minimize the neurons themselves or find a more efficient algorithm. But on the other hand, their brains being comparable in size to ours is a good reason to think their intelligence was basically comparable to ours.
FWIW this study suggests that Neanderthals and modern humans might have had very different approaches to language: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4766443/ Neanderthals and modern humans both evolved to make sophisticated vocalizations, but it's possible that the Neanderthals had 10000 words yet only a few ways to join them in simple sentences. (E.g. what if Neanderthals couldn't ask questions, only state disagreements?) In particular we know that humans can have local brain damage leading to near-total disability in using language while still being able to comprehend language, so you could see ancient hominids being "as smart as modern humans" in terms of general problem-solving - building tools, administering medicines and performing surgeries, long-term planning around food - but having profound blocks in language that prevented them from forming larger societies. Neanderthals tended to live in small family groups, whereas almost every modern human hunter-gatherer lives in a much larger tribe (absent war or disaster).
The point that we shouldn’t speculate too much about the implications of Neanderthal brain size is well taken.
But IMHO it applies just as well when trying to show that Neanderthal’s language was super different from ours. We know virtually nothing about the evolution of language in our own species, let alone another species.
They were different for sure, but the fact that we regularly mated with and formed families with Neanderthals and their first few generation generations means to me that the difference wasn’t that much. I’d go so far as to that absent any reason to believe otherwise, the default presumption should be that we’d be close to equals with them in these matters.
> They were different for sure, but the fact that we regularly mated with and formed families with Neanderthals and their first few generation generations means to me that the difference wasn’t that much.
To be clear there's only genetic evidence of admixture, not any evidence that humans and Neanderthals actually coexisted as families. Mating between humans and Neanderthals definitely wasn't "regular" since there's not actually very much neanderthal DNA in modern humans. Maybe we had an enormous number of infertile children, but I don't think human hunter-gatherers would survive that since rearing and raising a child is so costly.
In particular there's very good reason to suspect that we didn't form families with Neanderthals in the way you are suggesting[1]:
> No evidence of Neanderthal mitochondrial DNA has been found in modern humans. This suggests that successful Neanderthal admixture happened in pairings with Neanderthal males and modern human females. Possible hypotheses are that Neanderthal mitochondrial DNA had detrimental mutations that led to the extinction of carriers, that the hybrid offspring of Neanderthal mothers were raised in Neanderthal groups and became extinct with them, or that female Neanderthals and male Sapiens did not produce fertile offspring. [...] As shown in an interbreeding model produced by Neves and Serva (2012), the Neanderthal admixture in modern humans may have been caused by a very low rate of interbreeding between modern humans and Neanderthals, with the exchange of one pair of individuals between the two populations in about every 77 generations.
Even if it was 1 pair in 5 generations, that's simply not high enough to suggest a strong common humanity based on admixture alone. Pulling this all together, I don't think there's any real evidence that humans and Neanderthals co-parented or had any other real integration between their societies. There was just occasional admixture.
I am sure there's a paper somewhere but I've never read anyone actually rule out what is IMO the simplest explanation: Neanderthal men occasionally raped modern human women and the child was raised among modern humans (the reverse situation explains why children with Neanderthal mothers and modern human fathers would have been raised among Neanderthals).
// not any evidence that humans and Neanderthals actually coexisted as families. //
There is not much evidence, but it's going too far to say there's no evidence. The evidence is their genetic heritage in us. There are many ways that that genetic heritage could have got there, ranging from rape to adoption to romeo-and-juliet style romances. The genetic admixture is evidence for all these routes.
// IMHO the simplest explanation: Neanderthal men occasionally raped modern human women //
That's one way it could happen, but we don't have anywheres near enough evidence to conclude that was the only way it happened, or even that it was the most common way it happened. All other hypothesis are still on the table.
And, certainly the first generation hybrids were welcomed in human families. Don't forget, in the Pleistocene, there was no such thing as being alive without being a member of a family.
I happen to be reading Sapiens right now. The author seems convinced that we genetically developed the ability for abstract thought (which he calls imaginary or fiction), and that allowed us to cooperate much more easily in large numbers. For instance, believing in a particular flag allows you to identify your allies on the battlefield without having ever met them before. The theory goes that other animals, including other hominins, genetically lack the hardware to rally around a flag.
This also led to the notion of a shared culture across many individuals that can adapt much more quickly than genetic evolution.
(Unless I misunderstand, of course.)
The author squarely blames Homo Sapiens for wiping out the other hominins, pointing out how many other large species seemed to go extinct as soon as we arrived someplace new, even long before the Agricultural revolution.
Certainly our capacity for abstract thought is our superpower, but recall, we tried to spread to Europe for 200,000 years, and the Neanderthals always were able to push us back out again.
50,000 years ago, something changed . Maybe it was an increased capacity for abstract thought, but if so, that was a software and not a hardware development, because we had the same anatomy for 300,000 years. If we could implement the software, I don’t see why the Neanderthals couldn’t have done so, as they had even bigger brains than we do.
Part of the theory is that abstract thought enables culture, and culture enables much faster adaptation than genetic evolution. But still far from instant.
So maybe the abstract thought hardware was there for a long time before we got culturally coordinated enough to use it with full effectiveness to organize large groups capable of outcompeting Neanderthals.
>Since the last ice age we've been dropping like flies.
the last ice age was ~12,000 years ago. the latest evidence for any of these other branches of humans is 3x that many years ago. on the contrary, the human population has skyrocketed since the last ice age
> In a new review paper, anthropologists tally all of the fossils that have been clearly identified as Denisovan since the first discovery in 2010. The entire list consists of half a broken jaw, a finger bone, a skull fragment, three loose teeth and four other chips of bone.
Right... is that enough? Then:
> “What we have found out about Denisovans is that, from a behavioral perspective, they were much more like modern humans,” said Laura Shackelford, a paleoanthropologist at the University of Illinois.
How can anyone make those sorts of leaps, on the basis of a tooth and some bone chips?
> Dr. Shackelford said findings like these raised the possibility that Denisovans and modern humans coexisted and interacted for tens of thousands of years — though whether they communicated is unclear. “That’s really going down the rabbit hole,” Dr. Shackelford said.
What he's saying is we can't tell if these purported species communicated, on the basis of what seems to me to be super lightweight evidence. He said "communicate"!
Via DNA, it says. But I can't get to the bottom of why DNA analysis is considered to be solid, when there are examples of it being quite flawed, eg with these twin sisters:
Someone said that these consumer outfits are known to be trash - but I presumed that all DNA tests would end up going to the same labs, and those labs would use the same principles to test.
There is quite a big question for me about the validity of DNA as evidence, when it is possible to show how some tests fail.
Are you arguing that adding an anthropological interpretation over the top of the automatic testing adds value? Or that it is a fudge to make the automatic testing fit whatever criteria are required?
I think the argument was that mass produced testing is of lower quality than top scientific labs dedicating all their expertise on a specific sample or two.
They are not the same process at all. Commercial ‶automated″ kits only genotype you, i.e. look at a couple thousands of well known SNPs to put you in the group you share more with. Resolution is low, extrapolation is virtually impossible, but it's cheap and fast, and Uncle Joe can claim his 15% Italian ancestry.
Work like those done on these denisovan is a whole other can of worms, which is still a very vibrant field (https://en.wikipedia.org/wiki/Ancient_DNA) – at least it was when I left it a couple years ago. The main difference being that it's trying to sequence as much of the genome as possible, using the better preserved DNA molecules, typically in the teeth or some places in the skull. Then it's dozen of hours of menial work by specialized worker using protocols light-years ahead of what is done for the commercial kits.
To make a good ol' HN car comparison, it would be like saying that because some chain carshop once screwed your head gasket change, there is no way anyone could ever restore a Cobra.
Anything is possible, but it would kind of be like finding two pc-clones, both which contained a copy of MS-DOS, and concluding that each was independently programmed.
For the kinds of arguments which scientists use to support these claims, see "Altitude adaptation in Tibetans caused by introgression of Denisovan-like DNA" by
Emilia Huerta-Sánchez, et al.
It would be weird to have the same DNA sequence from convergent evolution, since even if evolution converged on exactly the same protein (unlikely as that may be), most amino acids in the sequence can be represented by several different DNA triplets and there is absolutely no reason why it should converge on the same triplets.
asians have a lot of denisovan dna too, and there are bone fragments originally attributed to denisovans that were found by DNA to be a 50/50 denisovan/neanderthal mix somewhere in the ballpark of modern uyghur territory atm iirc (some of the only denisovan pieces ever found i believe)
hybrids are usually unlikely to be able to reproduce but its not impossible depending on how distant they were, and we simply dont have enough evidence to deny they could have
so it could have been neanderthal-denisovan hybrids that went across asia for all we know
There's a non-zero chance that many of the asiatic H. Erectus[0] found during the late 19th and early 20th century are, in fact, Denisovans or their relatives, but were recovered in a period where our ideas about human migration were quite different from today's . . and long before genetic analysis[1]. When the remains are examined in their entirety, the variations are quite extreme, with brain sizes ranging from near-ape to practically modern.
[0] i.e., Java Man
[1] Revealing peoples like the Andaman islanders as having a high proportion of non-Sapiens non-neanderthal DNA, something that would fit into a 19th century anthropology not at all.
One thing I’ve been thinking about lately is whether there is the possibility of a frozen Denisovan or Neanderthal falling out of the permafrost somewhere in Siberia. The oldest mammoth found is around 30000 years old, so maybe a bit out of the ballpark.
During much of the Pleistocene, a million square miles of what is now sea floor north of Java all the way to Viet Nam and northeast to Korea, was prime bottom land rivaling Africa in richness and diversity. It would be unsurprising if that was where Denisovans flourished.
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[ 3.4 ms ] story [ 183 ms ] threadWhat chilling is that shows very clearly that humans can go extinct. In fact, humans go extinct all the time: 50,000 years ago, we shared the earth with at least 5 different varieties of humans (Homo Neanterthalensis, Homo Denisova, Homo Naledi, Homo Florensiensis, and Homo Luzenenensis). Probably also some late surviving populations of Homo Erectus and Homo Rudolfensis. Almost certainly more we'll never know about.
Since the last ice age we've been dropping like flies. In fact, we're the only humans left. And what with climate change, accidental nuclear war, or the singularity looming, we are arguably in a more precarious position than we've ever been.
EDIT: for those downvoting, I'd like to discuss why you don't agree. I mean, climate change, war, etc. What else can you call it?
If we launch all of our nukes, we might collapse civilization, but even that would likely leave humans around. We might get stuck in our gravity well for a long time, though.
Whatever makes us go extinct will either be cosmic or something we haven't invented yet.
We cool our bodies by sweating, a process which ceases to work at about 95 degrees at 100% humidity, or 115 degrees at 50% humidity. Its been estimated that an average temperature of above 122 degrees F would kill off all mammalian life on the planet.
Currently the earth is warming at about 1/3rd of a degree F per decade.
> Currently the earth is warming at about 1/3rd of a degree F per decade.
Every decade our technological capability increases dramatically. We're already working on climate engineering. Nothing here will extinct us.
See the July 19, 2022 Issue of the Scientific American, "How Hot Is Too Hot for the Human Body?"
// I would frequently go running //
Recall, it's 95 degrees at 100% humidity. The more humid the air, the less sweat will evaporate. I don't care if you are Jesus Christ Usane Bolt Superstar, above 95 degrees at 100% humidity, if you run long enough you will get heatstroke.
// Nothing here will extinct us // Extinction has happened to every other species of Homo. Every. single. one. I wonder how many of them accurately predicted when and why they would go extinct....
I was born and live in heat, so when I hear cold climate SF denizens say the end is nigh, I have to chuckle.
I took a look at your source [2]. I'll have to read the underlying literature. The way this is presented to a lay audience doesn't make it clear if they're controlling for acclimation. I'm not educated in physiology beyond an undergrad class, so I'm not sure if their measure is a good proxy.
It'll take sixty years to raise the temperature two degrees, after which I'll probably be dead. It'll take centuries to push into dangerous ranges. I think we're already building the tech to deal with this, and very little growth is exponential. This is going to be yet another sigmoid. And in geologic times, just noise.
I will say I am worried about loss of species diversity. But I'm more worried about a lack of cheap energy to fuel our ascendent climb to the next stages. And more worried about nukes.
As far as green tech goes, I've always been worried about particulate matter in the air leading to cardiopulmonary diseases. So it's not a bad thing and I've never once been against it.
What I am concerned about is that we're teaching Gen Z and Gen Alpha to just give up. Go look at /r/GenZ and all the threads about climate - these kids are just giving up on life because of these memes. In reality, their lives will not be impacted by climate change whatsoever. We're scaring them to death and their entire generation is experiencing trauma because of this.
We do need to control these systems, and we do need to protect ecosystem biodiversity, but this hysteria is ridiculous.
[1] I just measured the water temperature.
[2] https://www.scientificamerican.com/article/how-hot-is-too-ho...
Did you measure your body temperature? Were you able to cool yourself by sweating, or was your body temperature monotonically rising?
Recall, it is recommended that you go to a doctor if you have a fever of over 103 degrees, and over 108 degrees you risk brain damage.
Soaking some nice heat into your sore muscles in a 20-minute shower is one thing; but 24/7 your body is absolutely, positively not able to cool itself down is quite another.
// They don't control for so many things, let alone acclimation. //
Hey man, I gave you a source as requested. Whether or not evaporating water can cool down a body of a certain volume and surface when that body is internally generating heat--that isn't a matter of acclimation, its a matter of thermodynamics.
// after which I'll probably be dead // And why think about extinction after I'm dead, eh? :-) But far before 60 years passes, you'll find yourself in the age demographic for which death from hot weather is a risk. The body's ability to thermoregulate degrades as we get older, alas...
// worried about a lack of cheap energy // Wind farms are already cheaper to build than coal-fired plants. And if you factor in all the externalities, fossils fuels don't even come close to being a cheap source of energy.
// we're teaching Gen Z and Gen Alpha to just give up... this hysteria is ridiculous // Worrying about how the media affects "kids these days" is a normal, expected part of the aging process :-) ....maybe, perhaps, the thought that Gen-Z and Gen-X are just giving up is a bit, well, I won't say hysterical, but perhaps a bit hyperbolic? And inasmuch as they are going to be here longer than we are, they do have a bit more of a stake in the future than we do.
First, you've got those folks who are in deep denial about how much we've utterly fucked our climate, i.e. "don't look up, just vote down!" Included in this group are those who think/feel "things got better over the past 100 years, so the next 100 years must be better too!"
Then you've got the astroturfers who are paid to minimize any discussion of climate disaster for whatever reason; governments, political movements, oil companies, etc. I see those in comments on the larger newspapers, they swarm in and state contradictory "facts" that confuse people and shut down discussion.
Personally, after the experience of COVID-19, the inability of governments to give up the easy money from oil etc, and the lack of reaction to extreme weather events, I think humanity is utterly doomed. If anyone survives, I don't think there will be more than a couple million people left at the end of this century.
People talk about "oh we'll just do X, Y, and Z to fix things" while forgetting that we'll have to do those things while dealing with:
We are our own great filter.Do we also air condition the farms?
Even if that were possible, humanity has shown that we will only do something worldwide when we're absolutely forced to. We will not be able to do that while dealing with the disasters that come with global climate catastrophe and ecological collapse.
A refresher in thermodynamics is in order here....thermal energy is...energy, which is a conserved quantity. Heat doesn't just disappear. An air conditioner cools the inside air by making the outside air hotter.
And (thermodynamics strikes again) it also creates yet more waste heat in the process.
// if people are free //
Doesn't matter how free people or the markets are, thermodynamics is for real. We are not air-conditioning our way out of this.
The best counterargument to the population trend argument is that we're in the midst of a Wile E. Coyote period. Along with that though one still needs to account for:
- What's different about weapons today versus say 1970s?
- Why climate change, despite being a serious (and to be clear: actual risk), isn't amenable to solutions like the Montreal protocol that've succeeded in the past?
But sure the Montreal protocol and even the response to COVID 19 shows what can be accomplished should everyone work together. But it wasn't too late in either case then, and they were easier to solve. Today's weapons are definitely scarier than 1970s weapons.
Either way, I wasn't attempting a definitive list with my two items and "etc", I'd consider overpopulation as big a threat as climate change, the fact it's increasing each year is part of the problem.
I believe that would be after you've run off a cliff but before gravity has noticed.
The sibling reply expressed this as well. Wile E. runs off a cliff, the forward momentum keeps gravity in check but only for a short time.
The fact that human population continues to grow isn't by itself sufficient evidence that there are no existing parallel, possibly embryonic, trends developing that'll change that later. The period where both of these are true would be similar to when Wile E. is no longer on solid ground and hasn't yet fallen. It's a temporary and (on a relative basis, which could exceed human lifespan for sufficiently complex or slowly moving trends) brief period.
To be clear, I don't think it's an accurate view of where we are today. On the other hand, had the changes we've seen since 1970s not come to pass, it'd be harder to say. (An example that is climate change specific is the exponentially decreasing cost curve for solar energy.)
> Either way, I wasn't attempting a definitive list with my two items and "etc"
So long as the focus is on the definitive then IMHO there is value in looking hard here. Otherwise, why bother?
> Today's weapons are definitely scarier than 1970s weapons.
Can you say more?
[1] https://www.dreamstime.com/stock-photography-bingham-kenneco...
[2] https://en.wikipedia.org/wiki/Rice_Terraces_of_the_Philippin...
Open pit mines will fill with water. The sides will collapse. In the desert, they will fill with dust. Deserts often have flash-floods following thunderstorms. They might remain recognizable as hollows, but not much more.
The Bingham mine has had collapses in 2013 and 2021:
https://blogs.agu.org/landslideblog/2021/06/04/2021-bingham-...
https://blogs.agu.org/landslideblog/2013/04/30/analysing-the...
https://blogs.agu.org/landslideblog/2013/05/06/analysing-the...
There was a similar collapse recently at the Çöpler Mine in Turkey...
https://eos.org/thelandslideblog/copler-mine-1
https://eos.org/thelandslideblog/copler-mine-2
https://eos.org/thelandslideblog/copler-mine-3
https://www.youtube.com/watch?v=SUD0hQjueI0
https://www.youtube.com/watch?v=SCRTwnz3_oo
Climate change won't cut it, neither would total nuclear war.
Even if you had something like an impact big enough to superheat the entire atmosphere, enough humans might survive inside buildings, basements, subways, etc to carry on.
Modern civilization though is a lot more fragile. It's possible to blast us back to pre-industrial times and the easy to access resources are mostly gone. It's not clear that we could bootstrap a second industrial revolution easily.
There would be some increase in mortality among remote tribes as radioactive fallout from a large scale nuclear war drifted down globally, but that wouldn't be enough to cause human extinction.
[1] https://en.wikipedia.org/wiki/Uncontacted_peoples
Good luck getting them to adopt your useless ass in the post-apocalypse.
https://en.wikipedia.org/wiki/Permian–Triassic_extinction_ev...
This is a good point, but the event wouldn't need to be more volcanic so much as that volcanism would need to ignite more carbon-containing materials - naively I would expect there to me more "fuel" in the Earth than there was 300m years ago.
Minoans went from the thriving trading center of the Mediterranean with written language as old as Egyptian Hieroglyphics to seemingly irrelevant for a while during the Bronze Age because volcanic eruptions seemed to have turned the air they breathed to poison. Not to mention places allegedly hit by the fall of volcanic ash whose remains are so far deep we only speculate they lived there.
I’m really hoping this is a ironic literary reference to “How I learned to stop worrying and love the bomb”
https://en.wikipedia.org/wiki/IUCN_Red_List_of_extinct_speci...
And homo cyberneticus will do it to us.
Those were pre-human ancestors, but humans aren't special, we are just animals that are more destructive than any species that came before us.
Hubris will likely play a large role in any possible future human extinction event. E.g., doing nothing to curb climate change because we are "smart" and invincible and/or god(s) wouldn't allow things to get that bad, a deadly pathogen develops resistance to all antibiotics because of free-feeding antibiotics in factory farming animal flesh, we use nuclear weapons in conflict X believing it will not escalate (George "Baby" Bush, "I want nuclear weapons I can use" [actual quote]), a pathogen intentionally developed to both spread quickly and be extremely deadly (because we can), that somehow... "no one could ever foresee the possibility..." escaped the lab-- or maybe it will be a large meteor impact wiping out humans (and other large animals) across the globe like a kid stomping on an ant hill.
[1] https://www.scientificamerican.com/article/human-ancestors-n...
The linked article talks about the human bottle neck 900,000 years ago, that's almost a million years, but well short of 900 million.
I was under the impression that was our doing. All of these human varieties were outcompeted by homo sapiens who replaced them. Modern humans don't need to worry about another hominid taking their place because we're the last one standing.
E.g. For at least 200k years, we can tell by fossils from the middle east that we made many attempts to spread to Europe, but were always pushed back. Fun fact: Neanderthals actually had substantially bigger brains that we do today (their average size was about 1400-1500ccs. Subtract the volume of a tennis ball from that and you'll get the average size of our brains today). Neanderthals were smart, tough, mofos.
So what changed 50k years ago which finally let us succeed? Well, the climate was warming from the last ice age, and Neanderthals were very much cold-adapted hominids. Their short, stocky legs and heavy muscular arms were great at sneaking through the woods and stabbing a deer with a spear, but when the climate changed the woods disappeared, those short legs, hauling a very heavy upper-body musculature, were not so good at running the deer down on a plain.
Honestly, we have no real definitive answer to why we are here and they aren't. Like anything else, probably it was a complicated process in which lots of factors--including dumb luck--played a role.
For about 4 million years, the earth was very hospitable to all kinds of species of Homo--we find their bones, in a kaleidoscope of shapes and sizes, all over the old world. Since the last ice age, however, Homo has been having a really rough time of it. And we are the only humans left.
If you were locked in a room with 10 people, and one by one they started to disappear, when you were the only one left, you might wonder whether it would happen to you too.....
FWIW this study suggests that Neanderthals and modern humans might have had very different approaches to language: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4766443/ Neanderthals and modern humans both evolved to make sophisticated vocalizations, but it's possible that the Neanderthals had 10000 words yet only a few ways to join them in simple sentences. (E.g. what if Neanderthals couldn't ask questions, only state disagreements?) In particular we know that humans can have local brain damage leading to near-total disability in using language while still being able to comprehend language, so you could see ancient hominids being "as smart as modern humans" in terms of general problem-solving - building tools, administering medicines and performing surgeries, long-term planning around food - but having profound blocks in language that prevented them from forming larger societies. Neanderthals tended to live in small family groups, whereas almost every modern human hunter-gatherer lives in a much larger tribe (absent war or disaster).
But IMHO it applies just as well when trying to show that Neanderthal’s language was super different from ours. We know virtually nothing about the evolution of language in our own species, let alone another species.
They were different for sure, but the fact that we regularly mated with and formed families with Neanderthals and their first few generation generations means to me that the difference wasn’t that much. I’d go so far as to that absent any reason to believe otherwise, the default presumption should be that we’d be close to equals with them in these matters.
To be clear there's only genetic evidence of admixture, not any evidence that humans and Neanderthals actually coexisted as families. Mating between humans and Neanderthals definitely wasn't "regular" since there's not actually very much neanderthal DNA in modern humans. Maybe we had an enormous number of infertile children, but I don't think human hunter-gatherers would survive that since rearing and raising a child is so costly.
In particular there's very good reason to suspect that we didn't form families with Neanderthals in the way you are suggesting[1]:
> No evidence of Neanderthal mitochondrial DNA has been found in modern humans. This suggests that successful Neanderthal admixture happened in pairings with Neanderthal males and modern human females. Possible hypotheses are that Neanderthal mitochondrial DNA had detrimental mutations that led to the extinction of carriers, that the hybrid offspring of Neanderthal mothers were raised in Neanderthal groups and became extinct with them, or that female Neanderthals and male Sapiens did not produce fertile offspring. [...] As shown in an interbreeding model produced by Neves and Serva (2012), the Neanderthal admixture in modern humans may have been caused by a very low rate of interbreeding between modern humans and Neanderthals, with the exchange of one pair of individuals between the two populations in about every 77 generations.
Even if it was 1 pair in 5 generations, that's simply not high enough to suggest a strong common humanity based on admixture alone. Pulling this all together, I don't think there's any real evidence that humans and Neanderthals co-parented or had any other real integration between their societies. There was just occasional admixture.
I am sure there's a paper somewhere but I've never read anyone actually rule out what is IMO the simplest explanation: Neanderthal men occasionally raped modern human women and the child was raised among modern humans (the reverse situation explains why children with Neanderthal mothers and modern human fathers would have been raised among Neanderthals).
[1] https://en.wikipedia.org/wiki/Interbreeding_between_archaic_...
There is not much evidence, but it's going too far to say there's no evidence. The evidence is their genetic heritage in us. There are many ways that that genetic heritage could have got there, ranging from rape to adoption to romeo-and-juliet style romances. The genetic admixture is evidence for all these routes.
// IMHO the simplest explanation: Neanderthal men occasionally raped modern human women //
That's one way it could happen, but we don't have anywheres near enough evidence to conclude that was the only way it happened, or even that it was the most common way it happened. All other hypothesis are still on the table.
And, certainly the first generation hybrids were welcomed in human families. Don't forget, in the Pleistocene, there was no such thing as being alive without being a member of a family.
This also led to the notion of a shared culture across many individuals that can adapt much more quickly than genetic evolution.
(Unless I misunderstand, of course.)
The author squarely blames Homo Sapiens for wiping out the other hominins, pointing out how many other large species seemed to go extinct as soon as we arrived someplace new, even long before the Agricultural revolution.
50,000 years ago, something changed . Maybe it was an increased capacity for abstract thought, but if so, that was a software and not a hardware development, because we had the same anatomy for 300,000 years. If we could implement the software, I don’t see why the Neanderthals couldn’t have done so, as they had even bigger brains than we do.
So maybe the abstract thought hardware was there for a long time before we got culturally coordinated enough to use it with full effectiveness to organize large groups capable of outcompeting Neanderthals.
It's far more chilling to me that people ascribe value to genetic lines outside that ascribed by living, breathing people.
the last ice age was ~12,000 years ago. the latest evidence for any of these other branches of humans is 3x that many years ago. on the contrary, the human population has skyrocketed since the last ice age
There is no "homo denisova". They're called Denisovans.
Svante Pääbo refused to give them a Latin name or declare them a species because he thinks it's pretentious.
Right... is that enough? Then:
> “What we have found out about Denisovans is that, from a behavioral perspective, they were much more like modern humans,” said Laura Shackelford, a paleoanthropologist at the University of Illinois.
How can anyone make those sorts of leaps, on the basis of a tooth and some bone chips?
> Dr. Shackelford said findings like these raised the possibility that Denisovans and modern humans coexisted and interacted for tens of thousands of years — though whether they communicated is unclear. “That’s really going down the rabbit hole,” Dr. Shackelford said.
What he's saying is we can't tell if these purported species communicated, on the basis of what seems to me to be super lightweight evidence. He said "communicate"!
https://www.youtube.com/watch?v=Isa5c1p6aC0
Someone said that these consumer outfits are known to be trash - but I presumed that all DNA tests would end up going to the same labs, and those labs would use the same principles to test.
There is quite a big question for me about the validity of DNA as evidence, when it is possible to show how some tests fail.
Work like those done on these denisovan is a whole other can of worms, which is still a very vibrant field (https://en.wikipedia.org/wiki/Ancient_DNA) – at least it was when I left it a couple years ago. The main difference being that it's trying to sequence as much of the genome as possible, using the better preserved DNA molecules, typically in the teeth or some places in the skull. Then it's dozen of hours of menial work by specialized worker using protocols light-years ahead of what is done for the commercial kits.
To make a good ol' HN car comparison, it would be like saying that because some chain carshop once screwed your head gasket change, there is no way anyone could ever restore a Cobra.
This nobel winner’s lecture on the topic goes into the genetic details and covers how they make the more general conclusions
>In Tibet, Dr. Huerta-Sánchez and her colleagues have found a Denisovan gene that helps people survive at high altitudes
Can't it be simply convergent evolution?
For the kinds of arguments which scientists use to support these claims, see "Altitude adaptation in Tibetans caused by introgression of Denisovan-like DNA" by Emilia Huerta-Sánchez, et al.
East and South Asians, and Native Americans have higher Neanderthal DNA than Europeans.
Source: https://images.app.goo.gl/Q1JLpT6MqiubCHq18
hybrids are usually unlikely to be able to reproduce but its not impossible depending on how distant they were, and we simply dont have enough evidence to deny they could have
so it could have been neanderthal-denisovan hybrids that went across asia for all we know
[0] i.e., Java Man [1] Revealing peoples like the Andaman islanders as having a high proportion of non-Sapiens non-neanderthal DNA, something that would fit into a 19th century anthropology not at all.
It seems like it would answer so many questions.
siberia i doubt though, and probably not neanderthals