March 7, 2013

Do species exist?

From the NYT:
Coming Soon: Long-Delayed Decisions on Endangered Species 
The eastern massasauga rattlesnake has been a candidate for protection since 1982, a legless bridesmaid, never a bride. Ditto the elfin-woods warbler. Like them, the Dakota skipper butterfly, a cucumber-bodied flier that zips unusually fast (for a butterfly) over the Minnesota and Dakota prairies, is dying out as development shrinks its habitat. It nevertheless has hung on, its candidacy deferred since 1975. 
Belatedly, the Interior Department’s Fish and Wildlife Service is giving them all — and 258 more — a thumbs up or down for protection under the Endangered Species Act, the 1973 law that was among the early triumphs of the environmental movement. 
It is evidence of the law’s travails that it took a federal judge to get them to this point. 

I haven't really read up on the Endangered Species Act since Charles C. Mann's series of articles in The Atlantic in the mid-1990s. Perhaps it has been amended since then? The 1973 legislation was hustled through Congress and signed by Nixon (who had bigger worries) without anybody thinking through the law's absolutist wording. The idea was to save the bald eagle and other charismatic megafauna, but nobody had any idea then just how many species there were in the United States (does anybody now?) Yet, the bill doesn't distinguish between wolves and weeds. A species is a species.

So, I presume, the unlimited demands of the legislation have mostly been blunted by not giving the bureaucrats a big enough budget to fully implement the ESA's fundamentalist language. But now a judge and the Obama Administration have negotiated a major expansion in coverage.
Under a 2011 settlement of two lawsuits by conservation activists, the wildlife service has pledged to decide the fates of all the backlogged species by 2018. A schedule issued by the service on Feb. 8 promised to decide by September whether to add 97 species to the endangered list, including 70 covered by the lawsuit settlement. 
Moreover, the service has finished preliminary work on more than 550 other potential candidates for the endangered-species list, almost all of which will be further evaluated after the backlog is erased. 
“They’ve dramatically increased the number of decisions they’re making — both positive and negative decisions, but the vast majority of decisions are positive,” said Kierán Suckling, the executive director of the Center for Biological Diversity, an Arizona conservation organization that is a party to the settlement. 
It is the most feverish activity on imperiled wildlife in two decades, an improbable feat amid ferocious attacks from conservative critics and in an economy with little money to spare for environmental frivolities. 
The wildlife service, the steward of most of the 1,400 species on the endangered list, casts the settlement as an opportunity to get back to its mission. 
... Skeptics might ask whether any species that can wait decades for listing was endangered to begin with. The answer, experts say, is that some aren’t; the wildlife service is likely to remove some from consideration after re-evaluation. But most of the rest are probably in declines lasting decades that would not be arrested without outside help. 
... Should many of the 800-plus species listed in the settlement be granted federal protection, as seems likely eventually, the endangered list could increase as much as 60 percent — and encompass more territory than ever before. ...
Developers are increasingly anxious over the possible listing of more than 400 freshwater mussels that live in rivers close to urban areas, mainly in the Southeast.

The mention of "more than 400 freshwater mussels" raises the central philosophical question about the Endangered Species Act that, as far as I can tell, remains unanswered: how do we know what is a species and what isn't? How do we know that the supposedly endangered San Fernando Spineflower is really a different species from the common San Gabriel Spineflower (the assumption that the answer to this question is yes derailed a billion dollar housing development in California). Do species exist? If so, how do you define them? How can the wolf-dog that lives down the block be two different species? 

If you think these questions sound familiar, yes, they are fairly analogous to the debate over whether or not race exists. The usual arguments are between those who view races as subspecies and those who point out the problems with the concept of subspecies. 

Yet, even the better established concept of species has many problems both in theory and in practice. Thus, there have been, last I checked, a couple of dozen different definitions of species put forward by biologists. Ernst Mayr proposed the simplest: interfertility defines a species. That's something you can wrap your head around. But there are problems. What about species that reproduce asexually? Among sexually reproducing species, how can you tell whether or not two of the 400 different types of mussels are interfertile or not? As we know from pandas, captive breeding programs are tricky. And what about types of animals who are interfertile but seem worth differentiating, such as dog, wolves, and coyotes?

In general, naturalists just look at animals and decide. (Linnaeus's stroke of genius was that he concentrated upon the reproductive organs, which meant that he was getting some indication of interfertility that way.)

Indeed, it was while I was thinking about the Endangered Species Act and the issues surrounding specieshood during the biodiversity debates of the 1990s kicked off by Edward O. Wilson's campaign to save the rainforests that led me to try to ground the study of human biodiversity in something less woozy than the notion of race as subspecies. Instead, I reasoned, something we know exists for every human is a genetic family tree and a biological extended family. If we go back to thinking about racial groups as extended families, one given a higher degree of coherence and endurance by partial inbreeding, then we have a stronger, broader concept that can be used in vastly more human situations than in just trying to differentiate continental-scale racial groups by skin color in the post-1492 world.

28 comments:

Anonymous said...

"And what about types of animals who are interfertile but seem worth differentiating, such as dog, wolves, and coyotes?"

But I must say an Eskimo dog looks and acts a lot more like a wolf than a chihuahua or pug.

Anonymous said...

http://en.wikipedia.org/wiki/Alaskan_Malamute

Anonymous said...

https://www.youtube.com/watch?v=TOZCbTeqUTE

It almost even howls.

Anonymous said...

We need an impact statement on the effects of illegal immigration on endangered species.

Ex Submarine Officer said...

The concept of species applied to reality of lifeforms is simply a case of applying a digital definition to an analog phenomenon

Anonymous said...

If you haven't seen (from October 2011):

http://www.quadrant.org.au/magazine/issue/2011/10/the-african-obamas

An Australian reviewer on English author Peter Firstbrook's: The Obamas: The Untold Story of an African Family.

Anonymous said...

I'd love to see someone argue against the ESA on the basis that species are a social construct using the same arguments used for race. Not really as I'm a species realist and environmentalist.

Marlowe said...

If one takes the Richard Dawkin's view of life there are no species - simply genes packaged inside billions of cells inside billions of bodies.

One then has to face the inevitable question: what is a gene? Identifying it poses problems.

Even before the neo-Darwinian synthesis most Darwinists saw evolutionary competition taking place between individuals and not species although some proposed species level selection as an additional process.

Anonymous said...

http://en.wikipedia.org/wiki/Species_problem

Anonymous said...

"The 1973 legislation was hustled through Congress and signed by Nixon (who had bigger worries) "

Steve, if you bother to do some research, you'll find Nixon was the prime mover in getting that legislation going. He told congress to craft the bill, they did, and he signed it.

Spend some due diligence on the Nixon's administration. The things he accomplished may surprise you.

Josh G. said...

"The idea was to save the bald eagle and other charismatic megafauna, but nobody had any idea then just how many species there were in the United States (does anybody now?) Yet, the bill doesn't distinguish between wolves and weeds. A species is a species."

A similar thing happened with historical preservation laws. The people who supported the initial passage of these laws mostly wanted to protect beautiful old buildings from being torn down and replaced with Modernist monstrosities. But now these laws are being used to landmark those very same Modernist buildings and ensure that they remain eyesores for all time. After all, they're "architecturally significant". The Christian Scientist Church had to go through years of bureaucracy to tear down the Third Church building in DC, an octagonal concrete fortress built in 1970. And even then, they only prevailed because Congress passed a law (the Religious Land Use and Institutionalized Persons Act) specifically giving religious organizations the right to challenge zoning and preservation decisions. Had the building been a private home or business, the owners would be out of luck and would have to indefinitely spend thousands of dollars to change a light bulb. (No joke - they literally have to put up scaffolding to get up there.)

Anonymous said...

A basic question that I don't think is being adequately considered is why do we want to save species from extinction in the first place? Is it to benefit our own species, or do species have some sort of moral right to exist that we are obligated to respect.

If the former (as I believe), then all species are not equally valuable and deserving of protection. Some are valuable to us because they are beautiful and impressive (lions, elephants, whales), some because they are interesting and informative scientifically (chimpanzees, the platypus), and some because they have commercial value (this would include that still undiscovered rain forest flower that cures cancer that we're always hearing about). But yet another species of sage grouse, so similar to the others that we've been missing the difference all these years, really has very little value to humans, and wouldn't be missed.

The way the law is written though, every species is of equal value, and equally deserving of protection. This only makes sense if species have some intrinsic value of their own that does not depend on their relationship to us. So where does that come from?

Anonymous said...

Nearly all “species” exist as populations that are reproductively isolated to various degrees. Some populations, like the Welsh and the Cornish are not very isolated from one another. Other populations, such as Pygmies and Inuit are very isolated. Same for nearly all other organisms.

Each population is evolving somewhat independently from other populations of the same “species”. For example, human populations living in tropical Africa evolve immunity to malaria, whereas populations in Tibet evolve high-altitude adaptations. Each population is going in a different evolutionary direction

As a result, within any species, we often see a wide range of genetic relationships (relatedness). In some cases, geographically separated populations can no longer interbreed and produce fertile offspring, although each adjacent population can breed with its neighbor (= ring species).

The bottom line is that there is no hard-and-fast definition for species. Instead most “species” exist as semi-independent populations that vary widely in there relatedness. Hence, it is the population that is important. The population is the evolutionary unit.

In humans, populations (races) are the important taxonomic units. If we want to preserve diversity, then we need to preserve each race, instead of our current program of destroying each independent human population by mixing all the races = destroying diversity.

Rex Little said...

Some interfertiity questions I've long wondered about:

1. Are dog breeds of greatly different sizes (Chihuahua/Great Dane, for example) interfertile?

2. Is there any combination of primate species (say, orang/chimp) which is interfertile?

3. Related to #2: has it ever been determined if humans are interfertile with any of our closest ape relatives, such as chimps? I realize that the experiment would be fraught with ethical problems, but surely there exist, or have existed, scientists who wouldn't be deterred by such.

Anonymous said...

To say that species are populations is to just put the question back another step. What the hell is a population? How do you group individuals into populations? You have the same problem as how to group individuals into species.

Anonymous said...

It's best to think in terms of 'gene pools' and species as being shared gene pools rather than the classic criterion of inter-fertility.

jody said...

"how do we know what is a species and what isn't?"

in biology, i believe the rule is that for organisms which use sexual reproduction, if a male and female can conceive a fertile offspring, they are the same species.

it is also possible that a male and a female of closely related organisms can conceive, and deliver a healthy alive offspring, but which are sterile. then the two organisms are not considered the same species.

species is not the same as race. in the taxonomy employed by formal biology, race would be the rank below species.

domain (kind of new as far as the highest division goes)
kingdom (the older highest division)
phylum
class
order
family
genus
species
(race would go here)

pat said...

I used to have a standard lecture on the distinction between analog and digital. As part of that talk I mentioned that humans were fundamentally digital. Many students refused to accept that. Usually the same ones who wouldn't accept that chimps shared about 98% of our DNA.

But DNA coding is discrete. The information is encoded in distinct lumps not a smooth pudding. Human DNA is a digital code that we are learning.

One day quite soon, computer coders will have tools with which to modify and create genomes. They will have editors and error correcting routines. The editors will contain help files and hints - just like common software tools have now.

Since editing and writing a DNA strand is so much like editing and writing standard software - I expect the change to happen very quickly. One of the first things the first generation of DNA coders will do is resurrect some extinct species. The Dodo seems like an excellent candidate. They are probably delicious.

But shortly thereafter when the public realizes that science can create just about any sort of creature that they care to, no one will care much anymore about endangered species. Kill 'em all. We can always make more if we want to.

Albertosaurus

Reg Cæsar said...

Kierán Suckling

He shoulda been a cop.

But 'Velma Potash-Suckling' does have a nice ring to it, n'est-ce pas?

Reg Cæsar said...

We need an impact statement on the effects of illegal immigration on endangered species.

Take out the word "illegal" and you're right on the mark.

Anonymous said...

The species that is most endangered is Homo KuKluxKlannis.

It must be saved or else 'progressives' will flip out and go mad. You see, liberals must feed on 'white hate'; and, if there isn't any, they start to cannibalize eachother by seeing KKK everywhere. So, even a liberal girl with a blanket can be mistaken for a KKK. By golly, I think I see one at a rock concert!!
It's like in LORD OF THE FLIES where kids began to almost hallucinate that one of their own is the bogey man and lynch him to death.

You see, that is the funny thing about ecology. Even 'bad elements' and pests have some use and purpose in the overall scheme. So, even though we don't like flies, flies also play a role. It gets rid of stuff like doogie and carrion by feeding on it with maggots.
We don't like spiders, but spiders kill insects.

During Mao's era, there was a movement to wipe out sparrows cuz them pests ate the crops. But when sparrows were killed, insect population went crazy. During the cultural revolution, cats were attacked and killed as 'bourgeois' pets, but then the rat population exploded. And Mao got rid of capitalists, but then, he began to miss them cuz the whole meaning of his life--and justification of his power--was 'class struggle' and hunting for capitalists.

White haters may be bad elements and nasty pests, but liberals must feed on hating them or else their lives are meaningless.
It's like once communists get rid of capitalists, they get to accusing one another of being 'capitalist roaders' since communism has no meaning without fighting capitalism.
And once Christians got rid of pagans and witches, they began to accuse other Christians of witchcraft. Christians lived on that stuff.
And the whole Holocaust Cult relies on seeing Nazis everywhere. There are some still in Sweden too, which is why we need a heroic tattoo-assed girl to fight them.

Liberals hate the KKK and white haters, but they feed off on that stuff. Hating the haters fills their moral tummies. With haters to vilify and feed on, liberals feel famished.

Since the KKK is going extinct, I say we put them on the endangered species list. Even if they are pests, they feed the egos of wonderful darling little liberals.

Anonymous said...

"Are dog breeds of greatly different sizes (Chihuahua/Great Dane, for example) interfertile?"

Yes, but they are not inter-fitful.

Anonymous said...

Coyotes are interfertile with dogs and wolves, but they are disinclined to breed with them. Coyotes are strictly monogamous and the male Coyote helps the female raise the pups so that she can have a larger litter. So a female Coyote who mates with a dog would have a lot of trouble supporting her pups on her own.

I guess you could call them the same species as the dog, but it would make sub-species a pretty important distinction.

Anonymous said...

Why are dogs more genetically flexible than cats?

Most cats are fundamentally alike in their physical dimensions whereas there are many kinds of dogs. Why is this? Diet? It seems cats can only eat meat and were meant to be hunters only. Dogs are mainly meat eaters but, like bears, also omnivorous when they have to be.

Is it due to emotional differences?
Dogs, being sociable, could be bred to serve different roles. Cats never listen and only wanna do their own thing, so it wouldn't have made sense to create different kinds of cats to do different tasks.

On the other hand, if we take the cat family as a whole, at least in size there seems to be greater divergence than among dogs.
Wolves are the biggest dogs, but they aren't that big.
But compare the kitty cat with the tiger. Huge difference.

But then, what if we include bears as a kind of dog? They are relatively closely related.

Foreign Expert said...

Humans and chimps, surprisingly, have a different number of chromosomes. They can't interbreed.

Anonymous said...

>Thus, there have been, last I checked, a couple of dozen different definitions of species put forward by biologists. Ernst Mayr proposed the simplest: interfertility defines a species.<

Too crude a definition, for instance - lion, tiger leopard and Jaguar can all interbreed, but would anyone deny that they are separate species?



Nick South Africa

ben tillman said...

Humans and chimps, surprisingly, have a different number of chromosomes. They can't interbreed.

Horses and donkeys have a different number of chromosomes. They CAN interbreed.

ben tillman said...

It's best to think in terms of 'gene pools' and species as being shared gene pools rather than the classic criterion of inter-fertility.

Which is essentially how Ernst Mayr did think. He saw the species as a small gene pool protected from too much variability by a reproductive barrier.

In other words, the species is a population adapted to a certain niche, and if the members of different species could interbreed with each other, too much genetic variability would occur, reducing the success of the adaptation. “The basic biological purpose of the species,” said Mayr, “is the protection of a harmonious gene pool.”