Poaching making China elephants evolve tuskless

[Sean]

http://today.reuters.com/news/newsAr...EPHANTS-DC.XML

BEIJING (Reuters) - Chinese elephants are evolving into an increasingly tuskless breed because poaching is changing the gene pool, a newspaper reported on Sunday. Five to 10 percent of Asian elephants in China now had a gene that prevented the development of tusks, up from the usual 2 to 5 percent, the China Daily said, quoting research from Beijing Normal University. "The larger tusks the male elephant has, the more likely it will be shot by poachers," said researcher Zhang Li, an associate professor of zoology. "Therefore, the ones without tusks survive, preserving the tuskless gene in the species." Since only male elephants have tusks, there were now four female elephants for each male in China, up from the ideal ratio of two, the paper said. Similar changes in elephant tusk development and sex ratios have been reported in Africa and India.

[Chris Weimer]

Sad, sad news, that such a beauty will one day be gone.

[tman_ndsu08]

The market is never sad, it simply is what it is.

[Matt W]

Sad that people simply view things in terms of economics rather than real life... :rolleyes:

This isn't purely about economics, tman, it's about changing the appearance of a species. For all time.

[tman_ndsu08]

Good, I'm glad they changed, they were ugly anyway.

[gallo]

There was a report some years ago that the same thing seems to be happening in Africa. There too, the selective pressure seems to be ivory poachers.

[MadKatz]

Humph! One-armed crabs are next then?

[gallo]

There is an article in the July/August issue of Natural History Magazine on elephants in North Luangwa National Park in Zambia. This population has been subject to heavy poaching. One of the effects has been to destroy much of the social structure of the elephant families. They usually live in matriarchial family groups in which all of the females are related and the males leave the family when they become sexually mature. One result has been that in the Park about 1/4 of the "families" are a single juevenile mother and her calf, and the average family size was cut in half in a span of about 10 years. There are few females older than 16 years left, the age at which they usually had their first calf. Now juveniles as young as 8 years are having calfs.

Recently, effective measures have been taken to eliminate poaching in Zambia. However, the elephant population is not growing. The studies seem to indicate that it is the result of the high infant mortality rate due primarily to the fact that about half of female elephants giving birth are still juveniles, and without the help of older females in the family, they aren't very good mothers.

The researchers also report that 38% of the elephants in the park are tuskless. In populations not subject to poaching, only about 2% are tuskless.

[Suburbanite]

Quote by: Matt W Sad that people simply view things in terms of economics rather than real life... :rolleyes: This isn't purely about economics, tman, it's about changing the appearance of a species. For all time.

Tusks suck anyways, they don't do anything too important except dig for water... maybe elephants will evolve to not need water in exchange

[castille]

Welcome to natural selection.

This is nature at its finest. Animals have to adapt to different environments, as do humans. Nothing wrong with it. Maybe you'd like to shake your first at comets because they killed off the dinosaurs who couldn't survive?

Contrary to popular opinion, humans don't control nature. Nature controls humans.

[orgaelin]

Humans *are* nature!

And in a way I have to say 'good for the elephants'. They may have to lose their tusks, but what a great way of insuring they get to survive! It's just about the only way to stop the poaching. Ask any elephant if it would prefer to die with tusks or live without... and it would probably just wander off! While complex, they're not complex enough to mourn the loss of tusks. And if humans miss the tusks, well it's all the better than missing the elephants.

[Lilith]

It's not survival of the fittest, it's survival of the most adaptable.

[gallo]

Quote by: Lilith It's not survival of the fittest, it's survival of the most adaptable.

Not sure of the context of your remark since no one has mentioned Spencer's theory of social economics, i.e., "survival of the fittest." Of course, as everyone is aware, Darwin didn't like the phrase and objected strongly to its application to his theory of natural selection. Nevertheless, it was the Christian and spiritualist Alfred Russel Wallace, the co-developer of the theory of natural selection, who finally convinced Darwin to use the phrase, mostly because its use had become so popular. Darwin used it in the 4th through 6th editions of his book, "On the Origin of Species." But Darwin never used it alone and always made a reference to natural selection in the same sentence.

But of course, "fitness" is a term that has meaning in a biological context, just as is "adaption." But they aren't what most people think. An adaption is a change in an organism that results in increased fitness. And of course, fitness is a measure of an organisms ability to produce a large number of offspring that survive to reproduce themselves. But those definitions have been arrived at since Darwin's time. The best description of Darwin's theory is differential reproductive success.

[JamesMcBride]

So what we've done is: Farm tusks out of evolution, then said "Well, tusks are ugly anyway". Nature decided that they weren't.

I think this is a terrible thing to happen to a species of beautiful animals!

[gallo]

Quote by: JamesMcBride So what we've done is: Farm tusks out of evolution, then said "Well, tusks are ugly anyway". Nature decided that they weren't.

Tusks always were a matter of evolution. Of the 8 families in the order Proboscidae with about 20 genera, all seem to have had tusks of some sort. Of course, all three of the remaining species in one family and 2 genera have tusks. It seems that they must have been useful, not a matter of beauty.

However, it seems that tuskless elephants now have differential reproductive success over and above those with tusks. So tusks are disappearing.

Quote by: JamesMcBride I think this is a terrible thing to happen to a species of beautiful animals!

Me too.

[Lilith]

Quote by: gallo Not sure of the context of your remark since no one has mentioned Spencer's theory of social economics, i.e., "survival of the fittest." Of course, as everyone is aware, Darwin didn't like the phrase and objected strongly to its application to his theory of natural selection. Nevertheless, it was the Christian and spiritualist Alfred Russel Wallace, the co-developer of the theory of natural selection, who finally convinced Darwin to use the phrase, mostly because its use had become so popular. Darwin used it in the 4th through 6th editions of his book, "On the Origin of Species." But Darwin never used it alone and always made a reference to natural selection in the same sentence. But of course, "fitness" is a term that has meaning in a biological context, just as is "adaption." But they aren't what most people think. An adaption is a change in an organism that results in increased fitness. And of course, fitness is a measure of an organisms ability to produce a large number of offspring that survive to reproduce themselves. But those definitions have been arrived at since Darwin's time. The best description of Darwin's theory is differential reproductive success.

Let me explain what I mean a little better, I'm not an expert on this and I'm not a scientist, but the way I see it is: If it can adapt, it survives. But like you said an adaptation in an organism then results in increased fitness. So whatever evolves/adapts the necessary means to survive and reproduces then it's the fittest.

But what looks like what's happening with these elephants is being speeded up by mankind.....kill all the elephants with the tusks, they don't have a chance to mate and pass that gene along, so that trait dies out. Sad.

Sad, the plethra of wildlife that is already become extinct due to man. Been studying about the Florida Everglades, that's a real travesty. We are actually pumping freswater into the ocean! so people living in South Florida wont get flooded! and due to overpopulation, the South Floridans experience water shortages! Does not make alot of sense to me....anyhoo, back on topic....*blush*

[gallo]

Quote by: Lilith Let me explain what I mean a little better, I'm not an expert on this and I'm not a scientist, but the way I see it is: If it can adapt, it survives.

As a species. Evolution is a change in the genetic makeup of populations over time.

Quote by: Lilith But like you said an adaptation in an organism then results in increased fitness. So whatever evolves/adapts the necessary means to survive and reproduces then it's the fittest.

I was afraid of that. You have just reduced survival to a tautology, one of the major objections to Spencer's "survival of the fittest." Only the fit survive. Who are the fit? Those who survive.

That's not what natural selection is. Natural selection is differential reproductive success. It is a statistical thing. It doesn't mean that organisms with less desirable characters never survive to reproduce, and it doesn't mean that those with the best characters always survive to reproduce. Differential reproductive success means that those organisms with beneficial characteristics TEND to reproduce more offspring. As a result, beneficial characteristics become more numerous in the population. That is the definition of biological evolution.

Quote by: Lilith But what looks like what's happening with these elephants is being speeded up by mankind.....kill all the elephants with the tusks, they don't have a chance to mate and pass that gene along, so that trait dies out. Sad.

While sad, I don't think that the evolution of elephants is being "speeded up." That would presume that there was a direction to elephant evolution that tended towards no tusks. That doesn't seem to be the case. The fossil record shows that tusks have been beneficial for the Proboscidae, since they all had them, some larger and some smaller. As I said in a previous post,

Tusks always were a matter of evolution. Of the 8 families in the order Proboscidae with about 20 genera, all seem to have had tusks of some sort. Of course, all three of the remaining species in one family and 2 genera have tusks. It seems that they must have been useful, not a matter of beauty.

As I pointed out in that post, tusk less elephants seem to have differential reproductive success today.

Quote by: Lilith Sad, the plethra of wildlife that is already become extinct due to man. Been studying about the Florida Everglades, that's a real travesty. We are actually pumping freswater into the ocean! so people living in South Florida wont get flooded! and due to overpopulation, the South Floridans experience water shortages! Does not make alot of sense to me....anyhoo, back on topic....*blush*

I agree.

[Lilith]

Well gallo, I guess really what's going on with these elephants has nothing to do with evolution, but extermination. Humans are killing them off faster than they can reproduce...so the elephants that are surving don't have the gene for the tusks to pass on.

Anyway, as far as my original statement....There was a point to it...but I guess I just came off wrong.

[bishop]

better they have no tusks than become extinct because they have tusks. elephants will last longer than the rhino, that seems to be for certain.

[gallo]

Quote by: Lilith Well gallo, I guess really what's going on with these elephants has nothing to do with evolution, but extermination.

Did you understand anything of what I said? Of course it is evolution. In non-poached populations of African elephants only about 2% are tusk less. In the poached populations tusk less elephants are as high as 38%. That is a change in the frequency of alleles in populations over time. I'm not sure of the dominance of the gene or genes for tusks, the it is genetic and it does change in populations that are poached. It seems that the heaver the poaching, the more quickly the ratios are changing. And even though humans are the selection factor, it is still natural selection since there is no intent to develop tusk less elephants.

Quote by: Lilith Humans are killing them off faster than they can reproduce...so the elephants that are surving don't have the gene for the tusks to pass on.

Right. But killing elephants faster than they can reproduce and killing the majority of elephants with tusks are not the same. Of course if the elephants are killed at a rate greater than they can reproduce, they will become extinct. However, tusk less elephants are less desirable so they tend to be poached less. Unfortunately, tusks aren't the only reason for poaching elephants.

Quote by: Lilith Anyway, as far as my original statement....There was a point to it...but I guess I just came off wrong.

OK. But I'm still not sure of what you were trying to say.