(For those who didn’t follow the link: the topic at hand was that of how it is that self-incompatible Nightshade plants—that is, Nightshades that have a very complex genetic mechanism preventing them from fertilizing themselves—continue to exist when self-compatibility/fertility allows for rapid growth of a population and diversification. The answer is that the various SI species are less likely to fixate on ‘bad’ genes, and thus be less vulnerable to disease. So while the individually selfish SC strategy yields short-term gains, the long-term gains of the SI-cooperating species causes them to collectively persist. The cheaters lose and the cooperators win. As a group. This gets more interesting when you consider that with species this close, cross-fertilization / hybridization has a relatively high fertile-offspring rate, meaning that there’s actually gene flow across species.)
The “species cannot breed with each other” thing seems like an argument from definitions on Eliezer’s part, because while there are often genetic, fertility, life-strategy and longevity issues with hybrids, they’re not all sterile, and they’re not all maladaptive. Indeed, there are some situations where hybridizing at the expense of the “pure” populations turns out to be an adaptive strategy. This can even be done in the lab with fruit flies.
Wild hybrids of fin and blue whales aren’t uncommon at all (we don’t know much about their lives as yet, though we’ve recorded them for quite a while now). Coyotes and wolves interbreed so frequently that some genetic analyses indicate that red wolves may all constitute coyote hybrids, implying the entire species “canis rufus” originated as a cross. Wolf-dog hybrids are quite common in the US. Beefalo and Zubron hybridize domestic cattle and wild bison, and are perfectly viable (and common in agriculture). Wild populations of grizzly and polar bears seem to produce viable hybrids; a few are known both as wild encounters and captive-bred. At least some camelid and feline hybrids are also reproductively viable. There are many, many interspecific bird hybrids.
There have been one or two followups, but I don’t think Eliezer has changed his position.
He hadn’t as of a month ago. Quoth Eliezer: “Thus demonstrating that a sort of species selection can exist, because species can’t breed with each other and therefore can’t be infected by SC genes from other species, while group selection can’t exist, SC always infects.”
(For those who didn’t follow the link: the topic at hand was that of how it is that self-incompatible Nightshade plants—that is, Nightshades that have a very complex genetic mechanism preventing them from fertilizing themselves—continue to exist when self-compatibility/fertility allows for rapid growth of a population and diversification. The answer is that the various SI species are less likely to fixate on ‘bad’ genes, and thus be less vulnerable to disease. So while the individually selfish SC strategy yields short-term gains, the long-term gains of the SI-cooperating species causes them to collectively persist. The cheaters lose and the cooperators win. As a group. This gets more interesting when you consider that with species this close, cross-fertilization / hybridization has a relatively high fertile-offspring rate, meaning that there’s actually gene flow across species.)
The “species cannot breed with each other” thing seems like an argument from definitions on Eliezer’s part, because while there are often genetic, fertility, life-strategy and longevity issues with hybrids, they’re not all sterile, and they’re not all maladaptive. Indeed, there are some situations where hybridizing at the expense of the “pure” populations turns out to be an adaptive strategy. This can even be done in the lab with fruit flies.
Wild hybrids of fin and blue whales aren’t uncommon at all (we don’t know much about their lives as yet, though we’ve recorded them for quite a while now). Coyotes and wolves interbreed so frequently that some genetic analyses indicate that red wolves may all constitute coyote hybrids, implying the entire species “canis rufus” originated as a cross. Wolf-dog hybrids are quite common in the US. Beefalo and Zubron hybridize domestic cattle and wild bison, and are perfectly viable (and common in agriculture). Wild populations of grizzly and polar bears seem to produce viable hybrids; a few are known both as wild encounters and captive-bred. At least some camelid and feline hybrids are also reproductively viable. There are many, many interspecific bird hybrids.