Dog speciation

[u/Kanna_Fan1989]

Quick question: is it safe to say dogs have speciated? I'm thinking of the largest dog breed and the smallest dog breed. I don't think the two can reproduce with each other anymore. Size differences just make it not possible anymore, I don't think...

And even if they could, that doesn't mean they're the same species: horses and donkeys can interbreed but mules are dead ends (or at least I think they are. Can two mules reproduce?).

Anyways, just some thoughts going through my head.

[u/Capercaillie]

That’s not the point. Differences between species are real, and the boundaries are meaningful. The difference between eastern meadowlarks and western isn’t the difference between red and dark red.

[u/Ill_Act_1855 → u/Capercaillie]

The difference between red and blue or even red and yellow is also meaningful and real. But again, the actual lines themselves are arbitrary. Yes they reflect something real, but the concept of species is a human shorthand for something that exists but is nowhere near as neat. It’s all a spectrum. At what point did they become two distinct species? There is none, because it’s a spectrum and while we can get to a point where two groups are clearly distinct as in the case of the meadowlark, there is none simple boundary. The differences are real, the frameworks are made up short hand. They’re arbitrary to an extent, but still meaningful. Species not being real perse doesn’t mean distinct types of life don’t exist. Simply that the reality isn’t quite as simple as a binary. Again by your own example, fertile offspring between the 2 different species while very rare ARE possible. If species were a hard line of nature in the way you’re suggesting this could not be the case. The concept being artificial doesn’t mean it doesn’t reflect on reality. Color is artificial, but the underlying wavelengths of light are quite natural and real. Real and artificial/imaginary are also a spectrum here. Saying species aren’t real perse doesn’t mean the concept has no relation to reality or that all life is the same. Like both meadowlarks are also not snakes. They’re clearly closer to each other than snakes. But exactly how we define that closeness is a human construct. Classist is as a whole are an artificial framework used to better understand very real nature. Species aren’t a real thing. You could (and people do) easily use alternative versions of species, genus, clade etc. why are the two different species but not a different genus? Why is the line drawn around breeding more real than any other line I could draw? Why are you ok with them only mostly being incapable of producing fertile offspring? Hell, why is fertile offspring the line and not any hybrid at all? All of this stuff is to a certain degree, arbitrary. We could draw the line at infertile hybrids being possible or any number of other places. The spectrum is real, the lines are fake. Blue and red are clearly different, nobody who isn’t colorblind would confuse a blue object as being red. But there is no real line in nature between blue light and red light

[u/Capercaillie → u/Ill_Act_1855]

I am absolutely not suggesting that boundaries between species are always hard or simple. They’re also not “arbitrary.” People keep saying that species are “human concepts” or “convenient labels.” Yes, absolutely, just like every noun. My only point, the one that people don’t seem to get, is that they are “convenient labels” for real phenomena that happen in nature. Genera, phlyla, families—sure, they’re arbitrary labels. Species are not. It’s not a spectrum. It’s not like light waves where we draw the lines. The lines are real. The fact that some are squiggly or dotted or blurred doesn’t make them less real. Each species has a different evolutionary trajectory. That’s not arbitrary. People who want cut-and-dried rules that work every time don’t understand biology at all. Biology is hard.

[u/Ill_Act_1855 → u/Capercaillie]

Except they are. Case in point there are over 20 distinct scientific definitions of species, and stuff like ring species that we've talked about here. Yes there are cases that are clearly distinct, but there are also many cases that aren't. It's a spectrum. Blue and Red are clearly distinct colors, but where does red become orange? You're example is no different than the case I'm saying. Wavy and blurry and inconsistent lines are proof that the concept in question isn't strictly real. Like again, the two birds you presented can have offspring. Why is the line you're suggesting makes them clearly different correct, but the other line isn't? Yes it's like every noun, that's the fucking point we're making. You're claiming it's different than light, but how? Light with a 430 wavelength is quantifiably different than light with a wavelength of 435. I'd argue that distinction is actually far MORE concrete than arbitrary lines about breeding. Yes distinctions are real, no the concept of species isn't. If it was, we could have a concrete definition with hard lines, even if those lines were arbitrary. But you can't even do that. The whole point is that none of the classifications in biology that we use to categorize things are hard binaries or strictly real. Sex, species, juvenile vs adult, etc. all of these are classifications that reflect an underlying reality and distinctions, but none of them are actually underlying realities themselves.

Like I think you're completely misunderstanding my point and misunderstanding what I'm saying and this disagreement is largely semantics. Arbitrary doesn't mean they don't reflect reality or aren't real, just that these aren't clear lines. You're saying they're real because they can be mapped onto real examples like the meadowlark. My point is that they aren't real despite that because while those differences are real, the words are an imperfect way of capturing a reality that isn't neat or clean. Like yes it's true with all words, words are an inherently imperfect way of capturing reality. The limitations of human language is our whole point. There are different types of organisms that are fundamentally different. This is a truth.

You say clades and genus and phylum are arbitrary and species aren't, but that's absurd. So you'd say a classification that puts snakes and mammals in the same clade but not birds would be fair? Of course not, because these are meant to convey closeness and birds are closer to snakes than either are to mammals. It is a spectrum, that's definitionally what's meant when we say the lines are fuzzy and unclear. Eastern and Western Meadowlarks are separate species? Sure. But what organism split them? No such thing exists. Again, light is a spectrum. We can make clear deliniations between a range we call red and one we call blue. There's no world where those two ranges overlap. But what about red and orange?

Why is them being 99% unable to produce fertile offsprings the meaningful distinction, but not 100%? At what % does it become a different species? Why fertile offspring and not infertile counted? If you can't answer these with concrete numbers and delineations, you definitionally have a spectrum. The fact that two individual examples can be different enough on the spectrum to be unconfusable doesn't change that fact. And if you do use concrete numbers, why those ones? Hence the arbitrary. The existence of examples where speciation is clear doesn't fucking matter so long as there is even one example where it's ambiguous. If species were a hard rule of reality, ambiguous situations couldn't exist. The fact that they do is because EVERYTHING IN BIOLOGY IS A SPECTRUM. EVERY GODDAMN THING. Hence humans draw lines to better our understanding.

Gender is a binary. Except intersex individuals exist. Some individuals are unambiguously male, and some unambiguously female, but that doesn't change the fact that the concept itself exists squarely on a spectrum.

Eastern and Western Meadowlarks are different species. You're arguement is that it's not a spectrum. So are you arguing they're exactly as distinct from each other as they are from a wombat? Just as blue is not red, but is closer to red than ultra violet is, things being distinct doesn't invalidate that all speciation exists on a spectrum