Hot Nun knows a species when she sees one. Obey the Sister.
After the smashing success of my Multiple Orcasms post which still brings considerable daily traffic to the blog from furries looking for orca and vore themed pornography, I couldn’t resist tiptoeing around cheeky references to bestiality once again; but this time the human interest in animal sex is strictly like-on-like and the link to pornography is in the tricky means of defining concepts that are both familiar and yet abstract.
Trying to define what is necessary and sufficient to designate a “species” is rather like the problem the US Supreme Court ran into when trying to define pornography. In the decision for Jacobellis v. Ohio, Justice Stewart coined a now famous phrase when trying to draw a line between protected speech and unprotected obscenity:
In saying this, I imply no criticism of the Court, which in those cases was faced with the task of trying to define what may be indefinable… I shall not today attempt further to define the kinds of material I understand to be embraced within [hardcore pornography]; and perhaps I could never succeed in intelligibly doing so. But I know it when I see it, and the motion picture involved in this case is not that.
Many definitions, while concrete, are rather relative and not absolute. Darwin failed to define species in his Origin of Species:
Nor shall I here discuss the various definitions which have been given of the term species. No one definition has as yet satisfied all naturalists; yet every naturalist knows vaguely what he means when he speaks of a species.
He goes on to say just how blurred that line can be:
I was much struck how entirely vague and arbitrary is the distinction between species and varieties.
The “species debate” is a problem that existed before Darwin and which continues today. The current tone of the debate has been most significantly influenced by evolutionary biologist Ernst Mayr whose definition of a species graces most modern textbooks:
species are groups of actually or potentially interbreeding natural populations, which are reproductively isolated from other such groups
I had a laugh when I read Ernst Mayr’s essay “What is a Species, and What is Not?” published in Philosophy of Science in 1996:
The term ‘species’ refers to a concrete phenomenon of nature and this fact severely constrains the number and kinds of possible definitions. The word ‘species’ is, like the words ‘planet’ or ‘moon,’ a technical term for a concrete phenomenon. One cannot propose a new definition of a planet as “a satellite of a sun that has its own satellite,” because this would exclude Venus, and some other planets without moons. A definition of any class of objects must be applicable to any member of this class and exclude reference to attributes not characteristic of this class.
It doesn’t help Mayr’s point that the International Astronomical Union had no formal definition for ‘planet’ at the time of his essay or for a complete decade after it. When they did finally vote on one in 2006, the former planet Pluto got downgraded to a dwarf planet leaving every science textbook published in the preceding 80 years obsolete and violating Mayr’s apparent rule that one can not propose a new definition that would exclude an existing member of a class. Pluto was declared a planet upon its discovery in 1930 and now it’s not even the largest “plutiod”–that honor falls to Eris, which was discovered in 2005 and found to be larger than Pluto which prompted Astronomers to actually look at the definition of what makes something a planet versus something else.
If you take a moment to look around the blogosphere this week, you’ll realize that the uncertainty of this issue is present just beneath the surface of numerous topics of conversation:
Retrieverman asks if the Island Fox is a valid species which must be understood within the context of the greater Canid complex several species of which would violate the basic Mayr definition of a species, but his post on the Polar Bear is also framed by the species debate as genetic analysis shows that Polar Bears can be considered a variety of Brown Bear and the two can and do form fertile hybrids.
The Dog Zombie looks at Canid DNA to question the recipe of different flavors of “Canid Soup.”
Jess at Desert Wind Hounds picks up on the food metaphor at Dog Zombie and asks what the recipe is for a “purebred” and how one goes about creating one. This is ultimately just a more zoomed in analysis of the species debate: how much distance in time, space, genetics and niche constitutes a different breed, a different type, a different landrace, or a different species?
Stephen Bodio asks the same question with a simple image comparison of two dogs.
Razib Khan shows that the species debate is applicable to humans, and the notion that Neanderthals or Denisovians were somehow not human falls when you realize that their genes are still in us (Border Wars is written by a 2.7% certified Neanderthal):
In my post below I argue that it’s most useful to reconceptualize “human” as an ecological niche, rather than a descent group. All the confusion as to whether Neandertals, or any other group of divergent hominins, were, or weren’t, “humans like us,” exists in the context of the idea that “humans like us” are a very specific and sui generis cladewith special traits. I think “we” need to get a little off our high horse here.
You’ll notice that the notion of “niche” becomes more and more important as we realize just how blurry the lines between interfertile species really is. Niche is what separates Polar Bears from Brown Bears and it’s also what separates Dogs from Wolves:
The co-evolution between social canids and primates is I think not a random chance event. To some extent I think “man’s best friend” was a necessary outcome of evolutionary forces. Barring the total extermination of one lineage or the other, some sort of cooperative relationship is I suspect something that will naturally reoccur. Dogs are not simply a specific derived lineage of wolves, they’re an ecological niche created by the existence of hominins with social complexity.
Dave at Prick-Eared has a post which documents another canid rapidly invading the very niche that once brought man and wolf together to co-evolve.
There are no hard and fast answers here, no absolute definitions, no minimum standards or list of traits that are both necessary and sufficient to differentiate one “thing” from another “thing” in a meaningful way. This is the place where the objectivity of science meets the subjectivity of philosophy and those questions like “what is a dog” start to look a lot like “what is an ideal Afghan Hound.”
There are some questions that are worth answering “I don’t know and I probably never will, but that won’t stop the investigation.”
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When you read all these nineteenth century texts about wild dogs, they contrive species if they can. Any unusual mark instantly makes this animal a unique species.
There are always at least three or four different species of wolf. Coyotes and “prairie wolves” are deemed different species, with prairie wolves living in the United States and Canada and coyotes living in Mexico. The various subspecies of dholes are deemed species, and the dingo and pariah dogs– for no reason other than sharing a color and size– are always allied to these wild dogs.
Victorian science liked to split whenever they could. It would could give the “discoverer” some notoriety, and it also fit the Victorian racial concept that there were very different races of similar things. The Victorians themselves believed the Nordic peoples were superior and distinct from all the other races of human. At one time, they regarded the indigenous Australians as a different species of human and they would collect scientific specimens in the same way they would go out and shoot some new species of bird.
Now, because we have all of this wonderful molecular information, we have realized that the species barrier that they spent so much time contriving is really much more bogus than they assume.
BTW, just because you have a species complex with Canis lupus/Canis latrans doesn’t mean they are the same species. Just because you have interfertility with golden jackals and Ethiopian wolves and that species complex doesn’t mean that they are all one species. That’s as simplistic as trying to say that “prairie wolves” and coyotes are distinct species.
Retrieverman recently posted..Identify the quail
Yes, the lines between them are blurred, not invisible. They are there and there are plenty of areas of non-overlap.
With dogs and wolves, for instance, not only do we have niche aspects that are exclusive, we have morphological incompatibility issues. No Chihuahuas are going to bed any wolves any time soon. We also have to recognize that speciation is a LONG process and that the final irrevocable elements of that might not be dramatic. In some cases they are: there will be no human-chimp hybrids as we have a fused chromosome that is unlikely to pair with the two chimp chromosomes.
Indeed take the mule which is an offspring of a male donkey, and a female horse. A hinny offspring of a male horse and female donkey. Most male mules and most female mules are infertile. They are considered to be different species with different number of chromosomes. Likewise a Zebroid/zorse is another hybrid of a horse and zebra. Same reasoning for reproductive problems as far as I have studied. Kathy Bittorf
Chihuahuas probably won’t, but normal sized dogs and the smaller subspecies of wolves exchanged genes all the time. The accounts of Native American dogs interbreeding with wolves are legion. Wolves in Italy were once said never to exchange genes with dogs, but this has been proven false.
The problem I have is that they normally do exchange gene if humans aren’t shooting the wolves and the dogs are of normal size. Italy has black wolves and wolves with dewclaws on their hind legs– both traits come from dogs. Eastern European wolves are getting quite a bit of dog genes, though it’s not clear how much. The wolves in Italy don’t hunt prey– because there is none. They hang out at garbage dumps with hordes of free roaming and stray dogs. The two animals have the same niche. They exchange genes. Ergo, they are the same species.
The other problem you get is there are wolves– granted a minority of the population– that when socialized to people are actually not distinct from dogs. The wolf Adolph Murie had was a golden retriever that looked like an Alaskan wolf in both appearance and her DNA. Murie mentions another wolf that was like this in the same text.
You’re never going to get chimps that are like humans or humans that are like chimps, but you will get dogs that are like wolves and wolves that are like dogs.
Retrieverman recently posted..Golden girl in the gray woods
http://www.thebark.com/content/wolf-who-stayed
This is how I tend to think of it.
Retrieverman recently posted..Golden girl in the gray woods
True. There is theoretically a means to mix chihuahua DNA with wolf DNA without human intervention. Of course a male Chi could inseminate a female wolf under some complicated 3D geometry, but there is also an unbroken chain of dogs sized more equitably from Chihuahua all the way up to the largest wolf. If we look just at the extremes, natural mating would be rare if not impossible, but that forgets that we have a large and fine gradient in between.
There is plenty of diversity within Canis one could take advantage of, too bad so few want to use any of it.
I think that dogs will move into a ring species– just the domestic dogs. The small ones will eventually become reproductively isolated from the giant ones, but if wolves, dogs, coyotes, golden jackals, and Ethiopian wolves are still chemically interfertile, it’s going to take a while for this to happen.
Retrieverman recently posted..Golden girl in the gray woods
You might be able to get a humanzee, but the hybrid would have an odd number of chromosomes. It would be a Haldane’s rule hybrid in which one sex was never fertile and the other was occasionally fertile.
Humans have 46 chromosomes. Chimps have 48. A humanzee would have 47. This hybrid exists only in theory, but it is plausible.
Haldane’s rule doesn’t work all the time. Sometimes no viable hybrid is produced or they are fully fertile. Przewalski’s horse has 66 chromosome. The domestic horse has 64. The hybrid has 65, and it is fully fertile. It was on its way to speciation, but Przewalski’s horse had a massive gene flow from domestic horse strains, which is why we now consider it to be the same species as the domestic horse.
Retrieverman recently posted..Golden girl in the gray woods
I support the niche criterion for defining a species with a caveat.
In Italy, stray and free-roaming dogs and wolves have the exact same niche. They eat garbage. Dingoes and most wolves, even though they live in different parts of the world, essentially behave the same way in their respective ecosystems.
Dogs and wolves really aren’t separate species. You really have to bend the concept to make them separate species. You have to ignore dogs that behave like wolves and wolves that behave like dogs.
You will never confuse human behavior with that of a chimp, but there are wolves that make very nice dogs– they aren’t incredibly common– and there are dogs that live very nicely as wolves. That’s what a dingo is.
Retrieverman recently posted..The Canis lupus/Canis latrans species complex
I wish that more dog breeders would conceive this concept. Too many conceive that thier breed is unique and quite separate genetically from other canines. Best read thus far: “Dogs are not simply a specific derived lineage of wolves, they’re an ecological niche created by the existence of hominins with social complexity.” Well worth remembering. Kathy Bittorf
The recent uptick in these discussions has had me thinking about things I hadn’t considered before. I have a degree in Biology, and even in the advanced zoology classes, species were treated as a black and white issue. Sadly there’s very little discussion about species as more fluid, still-evolving populations.
Kind is starting to sound like a rather apt term.
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No, it’s really not. That word has no definition (decidedly inferior to a complex one), and it comes with bible baggage. “Kind” evokes the oldest and least sophisticated idea that life creating more life is fixed, permanent, stable, and that change is not possible. We know this is not true.
Science is not an answer, it’s a way of thinking, and that makes it decidedly the opposite of creationist ‘answers’ without reasons.
Our minds like clear and well-defined words to describe things.
The mind wants species to be easily categorized and definitive, but it’s just not that way.
Almost everything in nature is like this, and the desire of our minds to look for clarity and our tendency to try pigeonhole phenomena in order to make them clearer are keeping us from understanding much.
The trick is to see the muddled edges and appreciate where they are muddled and why they are muddled.
Kind is a very silly term that creationists use. With “dog kind” I’ve seen them include foxes with dogs, wolves, and coyotes. Foxes cannot cross with dogs at all, so they must have had a ton genetic mutations, enough to probably kill them, from the time their ancestors got off the ark.
Retrieverman recently posted..A long walk in the mud
I am a pattern-recognization machine in a universe of chaos and inconsistency.
People like boxes. The species box, the ‘responsible’ breeder box, the ‘good’ dog box. Putting things in boxes means they don’t have to think too hard, they can just assume and be on their merry way.
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If we take the maximum likely time for when dogs and wolves split from each other– 40,000 years– and compare that to the time when Ethiopian wolves split off the wolf lineage– 4,000,000 years ago, dogs and wolves have only began separate evolutionary journeys at a very recent time. Dogs and wolves have only gone down their paths at separate species for at most 1 percent of the time Ethiopian wolves have started their own. If we take the age from the dog genome sequence, dogs and wolves only began to separate around 27,000 years ago, which is an even tinier proportion.
Yet Ethiopian wolves can still hybridize with dogs and produce fertile offspring.
And then if you start looking at reproductively isolated very small dogs, well, they can’t be that old.
Retrieverman recently posted..The Canis lupus/Canis latrans species complex
Let’s just go with your statement.
A species is like how the courts have defined obscene porn, “you’ll know it when you see it.”
LOL
Retrieverman recently posted..The Canis lupus/Canis latrans species complex
Here are two hybrids that have the same chromosome number, but fertility and health issues are rampant in the hybrids:
http://www.petwebsite.com/hamsters/interbreeding_hamsters.htm
Chromosome number isn’t everything. It’s just one thing.
Retrieverman recently posted..Golden girl in the gray woods
Yes interesting is it not the microphalmic mutant eye of an “anophthalmic white” hamster. Described as a genetic syndrome or disorder in golden hamsters. Studies reveal ectopic nerve fiber bundles widely distributed.
http://www.ncbi.nlm.nih.gov/pubmed/6787209
The parallels to double merles and merle
ocular degenesis in dogs should be awakenings. Kathy Bittorf
Very similar to double merle: http://retrieverman.wordpress.com/2011/11/09/anophthalmic-or-eyeless-white-hamsters/
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Retrieverman recently posted..Arctic fox kills snow goose gosling
If you use the search function at Querencia– no time right now- you will find in my archives a long, linked evo- geek post shared between LabRat of Atomic Nerds and me about species definitions, sympatry, and more as exemplified by Saker and Gyrfalcons and whether they are separate species (NOT, IMAO). I think everything from Canids to Menno Schilthuizen’s theory about the possibility of sympatric speciation (he convinced Mayr) got in there. WE– two former evo- bio majors– loved it, but our readers replied with deafening silence. Lucky for them they didn’t have to read all the pages of correspondence that backed it up! Maybe folks here would find it more relevant!
Steve Bodio recently posted..Good day
The issues surrounding the Altai falcon are very similar to the ones surrounding the red wolf, which is just a glorified Eastern coyote, and the so-called Eastern wolf, which is a wolf with some coyote in it.
People have squeezed fossils, mtDNA, and microsatellite studies to make these animals into ancient and unique wolf species. when a large sample of the genome has been examined, they are simply coyotes or wolves with some ancestry from the other species. We’re currently wasting a lot of money to conserve a form of coyote in Eastern North Carolina– and it will eventually be swamped when they can no longer trap out all coyotes that are coming into that region on their own volition.
The red wolf silliness makes a mockery of wildlife conservation. We actually do have wolf subspecies that are genetically distinct– most notably the Mexican wolf and the Indian wolf, which are receiving next to no attention.
Retrieverman recently posted..California quail/bobwhite quail hybrid
Gosh, falcon taxonomy is totally FUBAR now that we are starting to use DNA to define species relationship.
This is far worse than what exists with the dog species, or even with ducks. (Mexican ducks, black ducks, and Mallards could all be the same species).
Retrieverman recently posted..California quail/bobwhite quail hybrid
Found the posts. First, with links to LabRat’s speciation thoughts, is Big Black Nemesis. Second, with reactions & thoughts by Wyoming entomologist and writer Jeff Lockwood, is Lockwood on Speciation. Definitely pertinent– enjoy!
Menno Schilthuizen’s Frogs Flies & Dandelions is also relevant good reading.
Steve Bodio recently posted..Good day