4 ms·

I have not seen the arguments against. What are they?

adolph 2y ago
My impression is that relatively recent genetic findings open "recent out-of-Africa" to conjectures of "its complicated mostly-out-of-Africa" https://www.edge.org/conversation/christopher_stringer-rethinking-out-of-africa https://www.edge.org/conversation/christopher_stringer-rethi...
- AlbertCory 2y ago
  I found this kinda hard to follow, but it doesn't seem UFO-level crazy, anyway. I'm sure this is ignorant, but: if two individuals can interbreed and produce fertile offscreen, then aren't they, by definition, the same species?
  - thaumasiotes 2y ago
    > if two individuals can interbreed and produce fertile off[spring], then aren't they, by definition, the same species? No. For example, that would make it impossible to determine the species of fossils. For another example, wolves are considered a different species from dogs, and coyotes are considered separate from each. For a third example, bacteria don't interbreed at all, but we don't consider each of them to be their own species. The definition you allude to is technically known as the "biological species concept", which should be a hint that it's not viewed as definitive.
    - AlbertCory 2y ago
      OK, thanks. What makes a wolf a different species than dog, and what species are the offspring of a dog-wolf mating considered?
      - thaumasiotes 2y ago
        Fundamentally what makes a wolf a different species than "dog" is that people don't consider them to be the same. But there are several good reasons; their behavior, life strategy, and often size and appearance are all radically different. The best match here is probably the "ecological species concept": (1) https://www.blackwellpublishing.com/ridley/a-z/Ecological_species_concept.asp https://www.blackwellpublishing.com/ridley/a-z/Ecological_sp... ; (2) https://en.wikipedia.org/wiki/Ecotype https://en.wikipedia.org/wiki/Ecotype > and what species are the offspring of a dog-wolf mating considered? I am not personally aware of standard terminology, but I might say "half wolf" or "wolf hybrid". The wikipedia page is titled "wolfdog". https://en.wikipedia.org/wiki/Wolfdog https://en.wikipedia.org/wiki/Wolfdog There is standard terminology for the offspring of a wolf and a coyote; those are called "red wolves". Wikipedia suggests that they have a taxonomic species name canis rufus, but this is controversial (since they're hybrids).
        AlbertCory 2y ago
        I do appreciate this and I hope you don't perceive it as "arguing." My biological education is a little sketchy. Turning it around a little: if some members of a mainland species move to an island and eventually become incapable of interbreeding with the original species, then it is always a new species. True or false? So "no-interbreeding" is sufficient but not necessary?
        thaumasiotes 2y ago
        > Turning it around a little: if some members of a mainland species move to an island and eventually become incapable of interbreeding with the original species, then it is always a new species. True or false? I think people would basically agree with this; true enough. > So "no-interbreeding" is sufficient but not necessary? Not quite; the example of bacteria, above, disproves the sufficiency of "no-interbreeding". (Bacteria do mix their genetic material, but they directly exchange it with each other, and then their children are clones of themselves. Imagine if, whenever you had sex, your partner took on some of your traits, and you took on some of theirs. This would obviate the need for your children to draw their traits from more than one parent, and that's how bacteria work.) There are asexual higher organisms, like some lizards, and they follow the taxonomic example of bacteria in that when two of them are genetically similar enough, we call them the same species despite the fact that - since they can't breed at all - they cannot interbreed. The fossil example is also incompatible with "no-interbreeding" being a sufficient criterion, though this is a bit less clear than the bacteria example; we can't determine whether two fossils were or weren't able to interbreed. We can be nearly certain that there is some pair of structurally similar-looking fossils out there that we have labeled as belonging to a single species, despite the fact that the individual organisms wouldn't have been able to breed with each other. You could make the argument that this is simply a mistake on our part, and that would have a lot of validity, but even viewed that way it's a mistake that cannot even theoretically be corrected, which causes some conceptual difficulties. The reason there are so many species concept is that species are just a reflection of the idea that two organisms are "the same". What it means to be "the same" varies in different contexts, according to, without claiming to be exhaustive, (1) what you care about; (2) what is possible in the space you're discussing [pigs can't do the direct genetic exchange that bacteria can]; and (3) what it's possible for you to know. > I do appreciate this and I hope you don't perceive it as "arguing." Don't worry about offending me; you seem to be in perfectly good faith so far.
otabdeveloper4 2y ago
> I have not seen the arguments against. How could you have seen any if the entire topic itself is a political hot potato and verboten to even discuss?
- AlexeyBelov 2y ago
  It's not, you can discuss it. Why don't you say anything of substance?

My impression is that relatively recent genetic findings open "recent out-of-Africa" to conjectures of "its complicated mostly-out-of-Africa" https://www.edge.org/conversation/christopher_stringer-rethinking-out-of-africa https://www.edge.org/conversation/christopher_stringer-rethi...

AlbertCory 2y ago
I found this kinda hard to follow, but it doesn't seem UFO-level crazy, anyway. I'm sure this is ignorant, but: if two individuals can interbreed and produce fertile offscreen, then aren't they, by definition, the same species?
- thaumasiotes 2y ago
  > if two individuals can interbreed and produce fertile off[spring], then aren't they, by definition, the same species? No. For example, that would make it impossible to determine the species of fossils. For another example, wolves are considered a different species from dogs, and coyotes are considered separate from each. For a third example, bacteria don't interbreed at all, but we don't consider each of them to be their own species. The definition you allude to is technically known as the "biological species concept", which should be a hint that it's not viewed as definitive.
  - AlbertCory 2y ago
    OK, thanks. What makes a wolf a different species than dog, and what species are the offspring of a dog-wolf mating considered?
    - thaumasiotes 2y ago
      Fundamentally what makes a wolf a different species than "dog" is that people don't consider them to be the same. But there are several good reasons; their behavior, life strategy, and often size and appearance are all radically different. The best match here is probably the "ecological species concept": (1) https://www.blackwellpublishing.com/ridley/a-z/Ecological_species_concept.asp https://www.blackwellpublishing.com/ridley/a-z/Ecological_sp... ; (2) https://en.wikipedia.org/wiki/Ecotype https://en.wikipedia.org/wiki/Ecotype > and what species are the offspring of a dog-wolf mating considered? I am not personally aware of standard terminology, but I might say "half wolf" or "wolf hybrid". The wikipedia page is titled "wolfdog". https://en.wikipedia.org/wiki/Wolfdog https://en.wikipedia.org/wiki/Wolfdog There is standard terminology for the offspring of a wolf and a coyote; those are called "red wolves". Wikipedia suggests that they have a taxonomic species name canis rufus, but this is controversial (since they're hybrids).
      - AlbertCory 2y ago
        I do appreciate this and I hope you don't perceive it as "arguing." My biological education is a little sketchy. Turning it around a little: if some members of a mainland species move to an island and eventually become incapable of interbreeding with the original species, then it is always a new species. True or false? So "no-interbreeding" is sufficient but not necessary?
        thaumasiotes 2y ago
        > Turning it around a little: if some members of a mainland species move to an island and eventually become incapable of interbreeding with the original species, then it is always a new species. True or false? I think people would basically agree with this; true enough. > So "no-interbreeding" is sufficient but not necessary? Not quite; the example of bacteria, above, disproves the sufficiency of "no-interbreeding". (Bacteria do mix their genetic material, but they directly exchange it with each other, and then their children are clones of themselves. Imagine if, whenever you had sex, your partner took on some of your traits, and you took on some of theirs. This would obviate the need for your children to draw their traits from more than one parent, and that's how bacteria work.) There are asexual higher organisms, like some lizards, and they follow the taxonomic example of bacteria in that when two of them are genetically similar enough, we call them the same species despite the fact that - since they can't breed at all - they cannot interbreed. The fossil example is also incompatible with "no-interbreeding" being a sufficient criterion, though this is a bit less clear than the bacteria example; we can't determine whether two fossils were or weren't able to interbreed. We can be nearly certain that there is some pair of structurally similar-looking fossils out there that we have labeled as belonging to a single species, despite the fact that the individual organisms wouldn't have been able to breed with each other. You could make the argument that this is simply a mistake on our part, and that would have a lot of validity, but even viewed that way it's a mistake that cannot even theoretically be corrected, which causes some conceptual difficulties. The reason there are so many species concept is that species are just a reflection of the idea that two organisms are "the same". What it means to be "the same" varies in different contexts, according to, without claiming to be exhaustive, (1) what you care about; (2) what is possible in the space you're discussing [pigs can't do the direct genetic exchange that bacteria can]; and (3) what it's possible for you to know. > I do appreciate this and I hope you don't perceive it as "arguing." Don't worry about offending me; you seem to be in perfectly good faith so far.

otabdeveloper4 2y ago

> I have not seen the arguments against. How could you have seen any if the entire topic itself is a political hot potato and verboten to even discuss?

AlexeyBelov 2y ago
It's not, you can discuss it. Why don't you say anything of substance?