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I thought species were defined as being broadly unable to interbreed? (Yes, mules and ligers exist but they’re exceptions to the rule produced by human interven

by taneq 6y ago

I thought species were defined as being broadly unable to interbreed? (Yes, mules and ligers exist but they’re exceptions to the rule produced by human intervention.)

sebmellen 6y ago
Yes, but Homo Sapiens interbred with Neanderthals and probably also Denisovans [1]. Different species, yes, but still able to interbreed to an extent. Where exactly the line between species lies is not so clear, even though it clearly exists, just like the line between red and orange. [1]: https://www.history.com/news/denisovans-interbreeding-discovery https://www.history.com/news/denisovans-interbreeding-discov...
- kebman 6y ago
  Is there evidence for that mating could only occurr "to an extent," like with horses and donkeys? Is there a physiological difference making it difficult for, say, difficulties in mating between Homo sapiens and Neanderthals, or between Homo sapiens and Denisovans? There can be a number of reasons for the two not mating often outside mere physiological differences, for instance differences in preferred culture, looks and personality. While some of that can certainly be the result of biological differences, it's not necessarily so. I'm just guessing and theorizing here, though, so any leads, links or breadcrumbs would be nice. :)
  - tharkun__ 6y ago
    https://aeon.co/essays/what-do-we-know-about-the-lives-of-neanderthal-women https://aeon.co/essays/what-do-we-know-about-the-lives-of-ne... This quote is from way down in the article but I think the most significant one: > Most intriguingly, something of the dynamics is visible. In some earlier instances, Neanderthal women had the children of H sapiens men, but the later interbreeding after 60,000 years ago tells a different story. Nobody today has mitochondrial DNA like that in Neanderthals and, since it’s passed only maternally, this implies that interbreeding was more often between their men and our women. Some other interesting ones: > unlike other primates, Neanderthal body size doesn’t seem to have differed much between the sexes. It’s much more similar to most H sapiens populations, which suggests that violent male competition was not the dominant social structure. Instead, more likely something akin to the bonobos, whose adult lives are based around long-term female friendships, might have been possible. > Somewhere around 40,000 years ago, the many generations of Neanderthal women become invisible, at least in skeletal terms. The processes underlying this must have come in many guises, in many places, but one thing we know is that women of another kind – H sapiens – played some part, because Neanderthals were not entirely extinguished. Just 10 years ago, the first nuclear genome was meticulously reconstructed from three genetically identified females at Vindija; it revealed that, rather than ousting Neanderthals from Eurasia, we had in fact interbred with them.
  - ojnabieoot 6y ago
    > Is there evidence for that mating could only occurr "to an extent," like with horses and donkeys? I am not sure what "to an extent" really means in this context, but modern-day Europeans and Asians have some distinctly Neanderthal and/or Denisovan genes. So, unlike mules, the children of (anthropologically modern) humans and Neanderthals were able to reproduce. In particular this has led some biologists to a rethinking of the Homo sapiens species as being many different (mostly extinct) subspecies: - Homo sapiens neanderthalis - Homo sapiens denisovan - Homo sapiens idaltu [1] - Homo sapiens sapiens (all currently living humans) An important disclaimer, as without context this stuff comes uncomfortably close to racist pseudoscience: compared to every other living species of primate, there is vastly less genetic variation among humans. This is despite the fact that there are far more humans than there are chimpanzees, gorillas, etc. Among the common chimpanzee there are many different subspecies, with distinct genomes. Chimpanzee subspecies are physiologically capable of cross-reproducing, but have intense social barriers that prevents it from happening in the wild (except in cases of rape). By contrast, modern humans only have one subspecies: Homo sapiens sapiens. Genetic differences between human groups are extremely subtle compared to chimpanzees, despite greater physical variation, and even the most bitter ethnic conflicts are nothing like the ancient socio-biological barriers found in chimps (they are transient on a biological timescale, and individual social/sexual relationships can still survive and flourish). So the ancient world of modern humans, Neanderthals, and Denisovans should really be seen as an ancient world with a variety of Homo sapiens subspecies, in an era where are genome was as variable and chaotic as the modern chimpanzee. What specifically happened to the Neanderthals and Denisovans is an open question, though their minimal contribution to European and Asian genomes suggests they weren't around very long as a distinct subspecies once modern humans came over from Africa. So, going back to "to an extent" - the children of modern humans and Neanderthal were biologically successful from the perspective of Charles Darwin, but a culturally disastrous from the perspective of a Neanderthals. [1] https://en.wikipedia.org/wiki/Herto_Man https://en.wikipedia.org/wiki/Herto_Man
ardit33 6y ago
wolf and dogs's offsprings can interbreed just fine, and have even more mixed offsprings, but they are considered different species "Wolves (canis lupus), coyotes (canis latrans), and domestic dogs (canis familiaris) are closely-related species. All three can interbreed and produce viable, fertile offspring — wolfdogs, coywolves, and coydogs. Through DNA analysis, scientists have established that the wolf is the ancestor of the dog."
- doubleunplussed 6y ago
  I always though dogs were "canis lupus familiarise" ans we're the same species as wolves - just a different subspecies or something.
  - doubleunplussed 6y ago
    Typos due to autocorrect (were -> we're is the dumbest autocorrect ever) and sloppiness: familiaris*, and*, were*
jccalhoun 6y ago
Read the article.
mannykannot 6y ago
If you are just taking a snapshot in time, that might just work. The problem over time, however, is that the descent, of each species so defined, is a long chain of breeding. There is a sorites problem in dividing it up into one species begetting another, as it is unlikely you will find offpring that could not breed with their parents' generation.

by taneq 6y ago

I thought species were defined as being broadly unable to interbreed? (Yes, mules and ligers exist but they’re exceptions to the rule produced by human intervention.)

sebmellen 6y ago

Yes, but Homo Sapiens interbred with Neanderthals and probably also Denisovans [1]. Different species, yes, but still able to interbreed to an extent. Where exactly the line between species lies is not so clear, even though it clearly exists, just like the line between red and orange. [1]: https://www.history.com/news/denisovans-interbreeding-discovery https://www.history.com/news/denisovans-interbreeding-discov...

kebman 6y ago
Is there evidence for that mating could only occurr "to an extent," like with horses and donkeys? Is there a physiological difference making it difficult for, say, difficulties in mating between Homo sapiens and Neanderthals, or between Homo sapiens and Denisovans? There can be a number of reasons for the two not mating often outside mere physiological differences, for instance differences in preferred culture, looks and personality. While some of that can certainly be the result of biological differences, it's not necessarily so. I'm just guessing and theorizing here, though, so any leads, links or breadcrumbs would be nice. :)
- tharkun__ 6y ago
  https://aeon.co/essays/what-do-we-know-about-the-lives-of-neanderthal-women https://aeon.co/essays/what-do-we-know-about-the-lives-of-ne... This quote is from way down in the article but I think the most significant one: > Most intriguingly, something of the dynamics is visible. In some earlier instances, Neanderthal women had the children of H sapiens men, but the later interbreeding after 60,000 years ago tells a different story. Nobody today has mitochondrial DNA like that in Neanderthals and, since it’s passed only maternally, this implies that interbreeding was more often between their men and our women. Some other interesting ones: > unlike other primates, Neanderthal body size doesn’t seem to have differed much between the sexes. It’s much more similar to most H sapiens populations, which suggests that violent male competition was not the dominant social structure. Instead, more likely something akin to the bonobos, whose adult lives are based around long-term female friendships, might have been possible. > Somewhere around 40,000 years ago, the many generations of Neanderthal women become invisible, at least in skeletal terms. The processes underlying this must have come in many guises, in many places, but one thing we know is that women of another kind – H sapiens – played some part, because Neanderthals were not entirely extinguished. Just 10 years ago, the first nuclear genome was meticulously reconstructed from three genetically identified females at Vindija; it revealed that, rather than ousting Neanderthals from Eurasia, we had in fact interbred with them.
- ojnabieoot 6y ago
  > Is there evidence for that mating could only occurr "to an extent," like with horses and donkeys? I am not sure what "to an extent" really means in this context, but modern-day Europeans and Asians have some distinctly Neanderthal and/or Denisovan genes. So, unlike mules, the children of (anthropologically modern) humans and Neanderthals were able to reproduce. In particular this has led some biologists to a rethinking of the Homo sapiens species as being many different (mostly extinct) subspecies: - Homo sapiens neanderthalis - Homo sapiens denisovan - Homo sapiens idaltu [1] - Homo sapiens sapiens (all currently living humans) An important disclaimer, as without context this stuff comes uncomfortably close to racist pseudoscience: compared to every other living species of primate, there is vastly less genetic variation among humans. This is despite the fact that there are far more humans than there are chimpanzees, gorillas, etc. Among the common chimpanzee there are many different subspecies, with distinct genomes. Chimpanzee subspecies are physiologically capable of cross-reproducing, but have intense social barriers that prevents it from happening in the wild (except in cases of rape). By contrast, modern humans only have one subspecies: Homo sapiens sapiens. Genetic differences between human groups are extremely subtle compared to chimpanzees, despite greater physical variation, and even the most bitter ethnic conflicts are nothing like the ancient socio-biological barriers found in chimps (they are transient on a biological timescale, and individual social/sexual relationships can still survive and flourish). So the ancient world of modern humans, Neanderthals, and Denisovans should really be seen as an ancient world with a variety of Homo sapiens subspecies, in an era where are genome was as variable and chaotic as the modern chimpanzee. What specifically happened to the Neanderthals and Denisovans is an open question, though their minimal contribution to European and Asian genomes suggests they weren't around very long as a distinct subspecies once modern humans came over from Africa. So, going back to "to an extent" - the children of modern humans and Neanderthal were biologically successful from the perspective of Charles Darwin, but a culturally disastrous from the perspective of a Neanderthals. [1] https://en.wikipedia.org/wiki/Herto_Man https://en.wikipedia.org/wiki/Herto_Man

ardit33 6y ago

wolf and dogs's offsprings can interbreed just fine, and have even more mixed offsprings, but they are considered different species "Wolves (canis lupus), coyotes (canis latrans), and domestic dogs (canis familiaris) are closely-related species. All three can interbreed and produce viable, fertile offspring — wolfdogs, coywolves, and coydogs. Through DNA analysis, scientists have established that the wolf is the ancestor of the dog."

doubleunplussed 6y ago
I always though dogs were "canis lupus familiarise" ans we're the same species as wolves - just a different subspecies or something.
- doubleunplussed 6y ago
  Typos due to autocorrect (were -> we're is the dumbest autocorrect ever) and sloppiness: familiaris*, and*, were*

jccalhoun 6y ago

Read the article.

mannykannot 6y ago

If you are just taking a snapshot in time, that might just work. The problem over time, however, is that the descent, of each species so defined, is a long chain of breeding. There is a sorites problem in dividing it up into one species begetting another, as it is unlikely you will find offpring that could not breed with their parents' generation.