Slashdot Mirror
Should We Just Call Dog Breeds a Different Species?
Jamie found an amusing bit this morning on Scientific American where the author proposes that dog breeds are different species. Now some of you might recoil when you hear this suggestion, but if you read the article to see why he makes this suggestion I suspect you'll crack a smile and appreciate the elegance of the solution.
You know what's funny? Dogs know dogs. They can be big, small, tall, round, thin, with or without tails, brown, red, white, spotted, yellow, shaggy, short haired, long legged, squat, etc, etc, etc. There is a massive amount of variation on display within the dog family.
But despite it all, dogs know dogs. Upon seeing another, they'll wag their tails or bark for a rotweiller the same as they would for a terrier. They'll all roam about in their little packs, somehow instinctively knowing they they naturally should.
And yet, if I have a man with different skin colour, or even simply different clothing, other men will consider his life worth less than even the smallest dog.
Makes you think.
May the Maths Be with you!
Just remember if you argue that dog breeds are different species, especially the case of the mastiff and chihuahua, or the teacup yorkie and newfoundland, these different species are verifiably the result of intelligent design. Selection was involved, but not natural selection.
Back in the 1800s there was this idea that all living things could be grouped into a neat, consistent classification system. As it turns out, reality isn't tidily organized like a giant clock.
Canis lupis is just a remarkably diverse species. Calling chihuahuas and wolves a different species is like calling Gary Coleman and Bao Xishun a different species. That is, completely ridiculous.
Arguing over where the line is between species is pretty dumb anyway. Nature is not divided into nice neat categories like that.
Give me Classic Slashdot or give me death!
Definite proof that cats are better than dogs.
How many cats lead blind people?
How many cats rescue injured people?
Perhaps serious scientists should stick with doing science, rather than refuting creationists and others with ideological agendas to push. Cause when you feed the trolls, the word gets around and you draw larger and larger numbers to be fed. Or in other words, one gets the impression that the refuters have an agenda of their own to push. Like the fine article, when one gets around to reading it, leaves behind.
It gets even better.
You cannot produce viable offspring with a chimpanzee. Neither could your great-great-great-grandparents produce viable offspring with that chimpanzee’s great-great-great-grandparents. But, go back enough generations, and your nth-great-grandparents gave birth to an individual whose far-distant offspring was that chimpanzee. Pick any other two organisms, and the same holds — it’s just that you have to go a little farther back in time to find the last common ancestor between, say, a squid and a butterfly.
We are all members of a single ring species that encompasses all of life on Earth. It’s just that the ring is separated by time, rather than geography or physiology.
And now you know the nutshell definition of the Theory of Evolution.
Cheers,
b&
All but God can prove this sentence true.
How much longer before a chihuahua can't breed with *any* other dog currently listed as the same species? Won't it happen eventually?
Domestic turkeys can't breed without human intervention - but they CAN breed with the help of humans, same as chihuahuas can (and have) been bred with large dogs when given a "helping hand" or "a leg up".
There's no such thing as a "pure-bred dog" - every single so-called "pure breed" is a mutt. The kennel clubs perpetuate the myth of "pure blood lines" because there's $$$ and ego in doing so. It's not like you can't get a phony "pure-bred" registration for a dog - as an experiment, people even registered CATS as "pure-bred dogs." Time magazine published an expose on this a couple of decades ago - your "breeding papers" would be better used to toilet-train the puppy than as any sort of guarantee of anything. And no, nothing has changed in the intervening years ... it's still a crock of horse manure that promotes cruelty to animals, puppy mills, reinforcement of bad genes, etc.
Those are all good examples of the problems with most simple definitions of "species". It's fairly common for intro biology classes (or textbooks) to go into these problems. There are many examples of what are sometimes called a "range species", in which nearby populations can interbreed, but more widely separated populations can't. There are a lot of example along shore lines, for obvious reasons.
Dogs are often used as an example of a slightly different problem: nontransitivity of the "same species relation". Domestics dogs can interbred with both jackals and the common gray wolf and produce fertile offspring, so you might be tempted to classify them all as subspecies of a single species. But if you crossbreed jackals and wolves, the offspring are usually sterile, so they're different species.
The lion/tiger case is an interesting problem. If you google for their hybrids, you'll find that whether or not the offspring are fertile depends on the sex of the parents and the sex of the offspring. The genetics is impressively complex.
Actually, these cases are handled by biologists via a simple caveat: If two populations can be interbred, but in their natural environments they don't do so, they're considered different species. The interesting part of this to biologists is studying the mechanisms that keep the populations apart.
One well-known case is that most North American ducks can interbreed, and the offspring are generally fetrile. So they're really all one species? No, because, although most hybrids are seen in the wild, they are exceedingly rare. The main separation mechanism is female selection. The males tend to approach any female duck during the spring+summer mating season, because they can't tell the females apart much better than we can (except for a few extreme cases like wood ducks). The females reject most of them, but accept the advances of males with the right color markings. Thus, a female mallard really wants to mate with a guy with a yellow beak and green neck (and the right wing bar), and a male without those colors is just too ugly to consider.
The occasional hybrids in the wild are sorta difficult to study, though, and not much is known about how they happen. The most reasonable hypothesis ("guess") is that the female's color-specifying genes are somewhat defective, so she isn't very good at picking the right guy. But it's not easy to test such things, since you can't watch all the millions of wild ducks, and in your lab, they will mate (eventually).
One fun example of problems with overly-simple definitions of "species" was from a bio prof who wrote on the board something like "Two individuals are the same species if they can mate and produce offspring." He asked the class what was wrong with this definition. I looked around, saw a lot of puzzled faces, and when nobody spoke up, I said what I thought was the obvious answer: "By that definition, you and I are different species." He and I were both male, so of course we could mate, but we couldn't produce any offspring at all. He just grinned, and went on with the lecture about other ways the term is defined, and the problems with all the definitions. I think I got a few brownie points for being able to point out the obvious problem with a definition you see all the time.
But it's yet another example of why you have to be rather careful in how you phrase your definitions.
And another "of course" is that the creationist crowd tends to pick their own definitions of "species", using definitions whose problems support their views.
Those who do study history are doomed to stand helplessly by while everyone else repeats it.