I am afraid that you are incorrect on several points. FIrst, that is not the question. You fundamentally misunderstood the OP’s question, as well as my own rephrasing of Gurdy’s question, which was, as OP said very clearly:
how do we see a pug and then a husky and understand that both are dogs?
given the extreme diversity of morphology in dogs, with many subsets of ‘dogs’ bearing no visual resemblance to each other, how am I able to intuit that they belong to the ‘dog’ set just by looking?
Or, as you rephrased it: “this may be a good way for us to recognize a dog if you meet one in the street”
Unfortunately you have answered the question “what is a dog” (which wasn’t asked) by describing “some characteristics of dogs” and concluding “dogs are a species of dogs.” That was never a question in this post, and it is not the answer to this question either, and you’re not quite correct about what a “species” is. But I am endlessly happy to talk about this at GREAT LENGTH. because your understanding of a species COULD BE BETTER. And by the end of this LONG POST it damn well will be. We are now going back to class.
Press J to skip it on your dash.
The answer to the question “what makes a species a species?” is not, as you put it, “well you see actually, a species is a species.”
A species is actually defined as a bundle of particular characteristics, which include what it can make babies with - but which remain a distinctive identity regardless of what that organism can fuck.
We don’t know how blurred the sexual/reproductive boundaries between the different types of prehistoric beasts were, on account of how you can’t intuit that from a single gatdamn fossil, but we sit down and give ‘em their own binomial names anyway, because we define species based on specific characters.
The reason we use the concept of “species” to begin with is because we need it to communicate; we know that domestic horses and wild zebras are necessarily distinctive, and we intuit that even though they can interbreed and produce occasionally viable offspring, they are not the same animal, and each has a discrete identity. Part of this is because technically they might breed, but they wouldn’t normally. (Nor would wolves and coyotes.) Another part is that they fulfill different niches and exhibit different natural behaviors. And still another part is physical characterisics; the adaptations of a zebra to its environment are unique, and it’s reasonable that they should contribute to the overall definition of “zebra.” Thus, if you were describing “a specific species of zebra” you reach for the traits that are distinctive - “A specific population of zebras, sharing characteristic appearance/behavior/territory/social structure/genetic quirk” - not a list of everything that they could conceivably fuck, and not an argument that two distinctive species of zebras are actually both horses. Animals within a species have more in common with each other than animals that don’t. Given all of the blurring that occurs around issues of reproduction, this is a fundamental part of the definition of a species.
Thus, stating that the complete and entire definition of a species as “animals that can breed” is itself extremely problematic, and shied away from by anyone who’s ever stood on the other side of the lecture podium.
Here’s what you say instead, when you’re an official adult scientist:
A species is a defined population of living organisms with a group of distinctive characteristics, which include the ability to exchange genes to produce fertile offspring that share those characteristics. Individuals within the same species have more in common with each other than they do with individuals outside of the species.
If you don’t hit every single one of those points in your definition, then you’re not going to get the right answer.
The better answer to the question “What is a dog” is actually more like:
“A domestic canine, Canis familiaris, is a terrestrial carnivore selectively bred over generations from a common ancestor shared with the modern gray wolf (Canis lupus) to suit specific human needs. The domestic dog exhibits extreme morphological diversity and has been bred for a large array of behaviors and characteristics, from herding other animals to providing medical aid. While dogs can breed with other canids and produce viable offspring, the domestic dog has distinctive characteristics, including a delayed period of childhood compared to wolves, increased attention and understanding of human nonverbal cues, increased ability to coexist with low aggression in close quarters with other species, and the ability to live on pet food made largely out of grain, which wolves can’t do, and which is pretty bloody weird if you think about it.”
That way, you’ve covered your goddamn ass. Because otherwise some perky undergraduate is going to put their hand up and ask “but what about wild coydogs?” And now you can answer, “Coydogs in wild settings, despite having domestic dog ancestry and being capable of breeding with other canids, are not considered domestic dogs because they do not share enough key characteristics with domestic dogs.”
“What about coydogs in domestic settings? Or my Aunt Maud’s wolfdog?”
“If a wild canid/domestic canid crossbreed meets enough criteria for domestic dogs, it would be considered a domestic dog. Your Aunt Maud’s wolfdog was in all probability just a husky with weird eyebrows anyway, but if it ate kibble, was allowed around children, and was completely emotionally fulfilled by living with humans in a house, it did not share the traits of wolves.”
“But what about black wolves?” will come a question from a reasonably well-informed kid at the back. “Black wolves are only black because of domestic dog ancestry. Does that make them dogs?”
“If they fulfill the role and function - the niche - of wolves, then we call them wolves,” I say with utter serenity.
“But what about infertile dogs that can’t breed with anything?”
“If they share the characteristics of domestic dogs, they remain dogs,” I reply, “Regardless of what would happen if they theoretically fucked a wolf.”
“What about beings that reproduce asexually, or without having sex?” asks a smart and clever student.
“Excellent question,” I say. “Aren’t you glad that our nice big definition of a species includes those awkward outliers too? Otherwise there’d be no point in having the word, now would there? We will note, though, that organisms such as bacteria are not usually defined by species, but by strain - a different word - since bacteria divide asexually and live everywhere at all times with no real regional differences, so ‘species’ no longer means much when you zoom in that far. After all, ‘species’ is only meant to be a useful concept for humans to sort animals with; it isn’t actually engraved in the genetic code anywhere, like a serial number that actually means something.”
The predictable hand goes up: “What if, like, dogs keep evolving? Like in the future, if people all evolve to live underwater and so do our pets?”
I answer first, “That would be weird,” in the traditional looking-over-the-tops-of-your-glasses flat affect; then I continue, “The current understanding of dogs is ‘terrestrial carnivore,’ so if they became fully adapted as aquatic carnivores I suppose we could call them their own species - a seadog descended from terrestrial dogs; or simply still call it a dog and expand the definition of dogness, like how we speak of ‘dialing’ a number even though phones no longer have physical dials. Both are legitimate; species boundaries are constantly being re-evaluated and redrawn, based on scientists learning new information about the species. Because the definition of a species is simply not limited to what it makes babies with.”
I pause, feeling like it would be irresponsible not to add a personal safety announcement here. “Also, do NOT presume to BEGIN to have this conversation with birdwatchers or Bird People. For your own safety, if you ever meet an ornithologist in a dark alley, forget COMPLETELY about this idea that the concept of a species is based even REMOTELY on “producing viable offspring.” The subtleties of different bird species can be characterized based on minor variations in song. People have meetings about this, at which they throw chairs. DON’T GET INVOLVED.”
“What’s the point then?” says a petulant student. “Like, if we all know what a dog is.”
And I reply, “Exactly! We invented language to communicate, and we impose it upon the natural world, drawing distinct and arbitrary boundaries in order to communicate, despite the natural world being a teeming, nebulous, essentially un-quantifiable n-dimensional hypervolume that resists such boundaries; Nature abhors a vacuum, and loves a grey area, but humans prefer to articulate abstract concepts using concrete language forms, even if doing so is fundamentally inaccurate.”
“But what if a Chihuahua fucked a wolf AND THEN-”
“RING SPECIES,” I bellow suddenly, interrupting a discussion that always degenerates into someone’s contorted furry/wolfkin/OC fantasies, by forcibly moving to the next slide: “ARE SAID TO OCCUR WHERE A POPULATION RINGING A GEOGRAPHIC OBSTACLE, SUCH AS THE SEAGULL POPULATIONS AROUND THE NORTH POLE, CAN BREED WITH THE POPULATIONS ON EITHER SIDE OF THEM BUT NOT WITH POPULATIONS ACROSS THE CIRCLE. EVERY DISTINCT POPULATION IS USUALLY CONSIDERED A SEPARATE SPECIES, AND -”
In conclusion, there is no shame in being wrong, but see how much easier it is to teach others, once you lay the groundwork for being correct?
Apologies to everyone else who was dragged along on this Magic School Bus ride, and went through the entire five stages of grief because of it.
