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ok. If we know that a species (1) is sexual, and (2) cannot interbreed with an individual of a superficially similar species, then it IS sufficient to say we ha

ok. If we know that a species (1) is sexual, and (2) cannot interbreed with an individual of a superficially similar species, then it IS sufficient to say we have two species there. I think I have all the qualifiers :) Incidentally, today on Facebook someone made the risible claim that since our DNA is 98% the same as a chimp, WE are "98% the same as a chimp." I pointed out that by that standard, we're also 60% the same as a banana.

thaumasiotes 2y ago
You might be interested in the concept of "ring species", which doesn't contradict the principle you just stated, but does conflict with the biological species concept. A ring species is a continuum of interbreeding populations such that the ends of the continuum are not interfertile. https://en.wikipedia.org/wiki/Ring_species https://en.wikipedia.org/wiki/Ring_species This parallels the phenomenon you see in languages where, for example, any two adjacent villages across a considerable distance will be able to speak to each other, even though villages at opposite ends of the continuum cannot do so. (The "ring" part of the term refers to the two ends of the interfertility continuum being located in the same geographic area, which is a red herring.) As the wikipedia page notes, the problem that this concept exposes is that interfertility is not a transitive relation, and therefore can't be an equivalence relation. > today on Facebook someone made the risible claim that since our DNA is 98% the same as a chimp, WE are "98% the same as a chimp." > I pointed out that by that standard, we're also 60% the same as a banana. The major problem here is that "to what degree is a person 'the same' as a chimp?" is not a well-defined question. Again, you would need to define what it means to be the same, and it will vary with what you care about. There are important ways in which we are the same as a banana; most obviously, you can eat a banana and expect to be nourished. This is not a given for an alien organism, even one that appears to be largely chemically identical to a banana. Whether the similarities reach 60% depends on how you convert them to numbers. We can note that the concept of 'species' assures us that any two humans are 100% "the same", as compared to a banana, whereas if you research relatedness the convention is that two brothers are 50% "the same" and two strangers are 0% "the same" (and bananas, not being human, don't exist), and if you're doing theology the convention is generally that even identical twins are 0% "the same". Summing that up, if you're told that two things are the same, the response is "the same how?" The reason the Facebook argument is stupid is that total shared DNA count isn't a useful thing to measure for most purposes. The salience of a difference in phenotype isn't closely related to the amount of DNA that changed to enable it.
- AlbertCory 2y ago
  and with that....... thank you, sir.

thaumasiotes 2y ago

You might be interested in the concept of "ring species", which doesn't contradict the principle you just stated, but does conflict with the biological species concept. A ring species is a continuum of interbreeding populations such that the ends of the continuum are not interfertile. https://en.wikipedia.org/wiki/Ring_species https://en.wikipedia.org/wiki/Ring_species This parallels the phenomenon you see in languages where, for example, any two adjacent villages across a considerable distance will be able to speak to each other, even though villages at opposite ends of the continuum cannot do so. (The "ring" part of the term refers to the two ends of the interfertility continuum being located in the same geographic area, which is a red herring.) As the wikipedia page notes, the problem that this concept exposes is that interfertility is not a transitive relation, and therefore can't be an equivalence relation. > today on Facebook someone made the risible claim that since our DNA is 98% the same as a chimp, WE are "98% the same as a chimp." > I pointed out that by that standard, we're also 60% the same as a banana. The major problem here is that "to what degree is a person 'the same' as a chimp?" is not a well-defined question. Again, you would need to define what it means to be the same, and it will vary with what you care about. There are important ways in which we are the same as a banana; most obviously, you can eat a banana and expect to be nourished. This is not a given for an alien organism, even one that appears to be largely chemically identical to a banana. Whether the similarities reach 60% depends on how you convert them to numbers. We can note that the concept of 'species' assures us that any two humans are 100% "the same", as compared to a banana, whereas if you research relatedness the convention is that two brothers are 50% "the same" and two strangers are 0% "the same" (and bananas, not being human, don't exist), and if you're doing theology the convention is generally that even identical twins are 0% "the same". Summing that up, if you're told that two things are the same, the response is "the same how?" The reason the Facebook argument is stupid is that total shared DNA count isn't a useful thing to measure for most purposes. The salience of a difference in phenotype isn't closely related to the amount of DNA that changed to enable it.

AlbertCory 2y ago
and with that....... thank you, sir.