NationStates Jolt Archive

Or rather, (un)natural selection, the driving force behind evolution.

A recent study has predicted that more male Asian elephants in China will be born without tusks because poaching of tusked elephants is reducing the gene pool, the China Daily reported Sunday.
...
The tusk-free gene, which is found in between two and five percent of male Asian elephants, has increased to between five percent and 10 percent in elephants in China, according to Zhang Li, an associate professor of zoology at Beijing Normal University.

http://news.yahoo.com/s/afp/20050717/sc_afp/chinaanimalselephant_050717075953


So how much more evidence do we need to declare that evolution occurs? We've got environmental pressures forcing adaptation even in the slowest and highly complex animals proven now, and it's only a matter of extrapolation to determine where this is going. Perhaps even in the long term the lack of tusks will lead to a split between tusked and tuskless elephants, creating a new species.

are you serious? assuming your information is correct, the de-tusked elephants didn't evolve from tusked elephants to adapt to people killing them off--it's just a recessive gene that already exists. if everyone with brown eyes were murdered by a hitler-like psychopath, the remaining blue eyed people would not have evolved from the brown eyed people, nor would their children. it would just be that all of the brown eyed people would be dead. that's not evolution.

are you serious? assuming your information is correct, the de-tusked elephants didn't evolve from tusked elephants to adapt to people killing them off--it's just a recessive gene that already exists. if everyone with brown eyes were murdered by a hitler-like psychopath, the remaining blue eyed people would not have evolved from the brown eyed people, nor would their children. it would just be that all of the brown eyed people would be dead. that's not evolution.

*sigh* Go read a science textbook, please. Natural selection is the mechanism by which evolution occurs. This is a perfectly reasonable example of natural (or, in this case, not-exactly-natural) selection.

It's also very sad. Poaching of endangered and threatened species really pisses me off...

I don't think that's because of poaching. I think it's because of a dominate mutation.

Or rather, (un)natural selection, the driving force behind evolution.

What is the (un) supposed to indicate?

What is the (un) supposed to indicate?

The fact that it is man, not nature, that is a possible causative factor for this adaptation.

What is the (un) supposed to indicate?

I believe the OP is suggesting that "ivory is pretty" is not the most "natural" disadvantage for elephants to have. One tends to associate natural selection with things like adaptation to climate change or lack thereof, intelligence, speed, and so forth, rather than with whether one's teeth would look nice on an ornamental knife handle.

Actually, you are talking about evidence, phenomena. You are showing an example of 'adaptation' that occurs in nature. It was this type of phenomena that needs explanation about 'why' it occurs. It is the 'what and why' of what Darwin was thinking about, and trying to answer when he made up the theory of evolution. The theory tries to say ‘why’ this is happening, not that it does happen.

You are talking about the evidence/phenomena, but it's not technically proof of anything besides what it is. Creatures adapt. Is evolution, i.e., natural selection, the reason they are adapting?

In this case, I'd have to say no. Evolution's natural selection has nothing to do with why they are adapting. I say this is nothing but proof that man has an impact on the number of elephants that produce tusks by eliminating the tusk producing gene... Game hunting with laws, fishing laws for size of legal fish, etc., has a good impact in the same way this tusk thing has a bad impact.

I would have to say that I disagree with the disagreeing. After all, the thing is, suppose the psychopath, after murdering all browneye people on the earth went and killed himself. The recessive genes in the remaing blue eyed people would continue to produce people with brown eyes.
However, with a more lasting threat such as poachers, it would make sense to have more elephants withouts tusks, just so that the species could survive. That is, after all, the rule of evolution. The survivors are the one who get to pass on the genes, because they must be good genes, or else how would the survivors have survived? Therefore, if the poachers kept on killing tusked elephants, they would get rarer and rarer, while the other population of tuskless elephant would get bigger. Whereas, with a psychopath event lasting a few decades maybe (at most) the browneye recessive gene would come through, so people would continue to have brown eyes.
Of course, the obvious problem with the tusklessness is the fact that tusks are so useful. Which is why at birth, we should replace elephant babies' tusks with plastic tusks for future use, and take the ivory ones away for our own maniacal convenience! :headbang:

Meanwhile, in Vatican City...

Swiss Guard: Your holiness! Its the elephants sir! They're evolving!
Pope: Ach! Zer Elephantz vill pay for zis betrheyal! SEND ZEM TO DER CAMPZ!
Swiss Guard: We dont have any camps Your Holiness, I mean, our entire country is a few miles wide, were the smallest country on the planet.
Pope: Blazt eet! Build szome camps! And dont let zer Italian government know about eet!
Swiss Guard: They already know...
Pope: Ach! Zer are spies in mien palace! KILL ZEM ALL!
Swiss Guard: No, your Holiness, they heard you yelling, see, theres a police officer over there.
Pope: Arrest heem! Do not let zee traitor geet away!
Swiss Guard: I cant really...I mean, I get laughed at enough as is, hint hint.
Pope: No, I like zer uniforms. Zey are cool!
Swiss Guard: We had better uniforms a hundred years ago.
Pope: Too bad! Arrest ze polize officar!

if being born tusked or not tusked depends on alleles, then tusked elephents being killed will change teh allele frequency. this is't evolution. but if there was a mutation, assuming tusks were single gene coded, then that could lead to evolution.

Actually, you are talking about evidence, phenomena. You are showing an example of 'adaptation' that occurs in nature. It was this type of phenomena that needs explanation about 'why' it occurs. It is the 'what and why' of what Darwin was thinking about, and trying to answer when he made up the theory of evolution. The theory tries to say ‘why’ this is happening, not that it does happen.

The point extactly. We're seeing in a creature natural selection in action, and the fact that this is occuring just as Darwin predicted it would (pressure on a species is allowing the less 'valuable' elephants to mature and reproduce, while the tusked elephants are being killed off, and thus can't reproduce) is a nice test of Darwin's hypothesis when it comes to natrual selection.

You are talking about the evidence/phenomena, but it's not technically proof of anything besides what it is. Creatures adapt. Is evolution, i.e., natural selection, the reason they are adapting?

It fits in with the hypothesis given by Darwin, so it suggests that Darwin's theory of natural selection is correct.

In this case, I'd have to say no. Evolution's natural selection has nothing to do with why they are adapting. I say this is nothing but proof that man has an impact on the number of elephants that produce tusks by eliminating the tusk producing gene... Game hunting with laws, fishing laws for size of legal fish, etc., has a good impact in the same way this tusk thing has a bad impact.
This differs from natural selection how? Peacocks are much the same way, they constantly have to strike a balance between mating displays and the fact that those displays have a habit of getting them killed. Same thing, except the elephants are the peacocks and we are the killers. Perhaps I was wrong with (un)natural selection at the beginning, it was just a catch line. Of course humans hunting is natural selection, I was just pointing out that generally this doesn't happen, so the conditions for the experiment are near perfect (we're the only variable effecting the tuskless gene, in that we are killing off tusked animals in large quanities. Darwin's hypothesis in this case would state that because the non-tusked animals are maturing and bearing offspring, then tuskless animals should increse as a preportion of the population as long as the pressure against tusked elephants exists).

*sigh* Go read a science textbook, please. Natural selection is the mechanism by which evolution occurs. This is a perfectly reasonable example of natural (or, in this case, not-exactly-natural) selection.

It's also very sad. Poaching of endangered and threatened species really pisses me off...


*sigh* Go read a science textbook AND a logic textbook, please. and while you're at it, you may want to pick up a dictionary. :)


But let's just all agree that poaching sucks.

I would have to say that I disagree with the disagreeing. After all, the thing is, suppose the psychopath, after murdering all browneye people on the earth went and killed himself. The recessive genes in the remaing blue eyed people would continue to produce people with brown eyes.
However, with a more lasting threat such as poachers, it would make sense to have more elephants withouts tusks, just so that the species could survive. That is, after all, the rule of evolution. The survivors are the one who get to pass on the genes, because they must be good genes, or else how would the survivors have survived? Therefore, if the poachers kept on killing tusked elephants, they would get rarer and rarer, while the other population of tuskless elephant would get bigger. Whereas, with a psychopath event lasting a few decades maybe (at most) the browneye recessive gene would come through, so people would continue to have brown eyes.
Of course, the obvious problem with the tusklessness is the fact that tusks are so useful. Which is why at birth, we should replace elephant babies' tusks with plastic tusks for future use, and take the ivory ones away for our own maniacal convenience! :headbang:
Accually, elephants need thir tusks for dgging up roots and occtionally fighting.

I would like to bring up that some people belive human poaching is "Natural Selection" but debating over if man is part of nature or not is like debating which is better: Sprite or Seirra Mist. Its differnt from debating "Is that Natelie that visted aruba dead". It has nothing to do with logic, just opinion.

if being born tusked or not tusked depends on alleles, then tusked elephents being killed will change teh allele frequency. this is't evolution. but if there was a mutation, assuming tusks were single gene coded, then that could lead to evolution.
I fail to see how a mutation must be involved for it to be evolution. Recall that we are talking about natural selection here, at the moment, which is the driving mechanism behind evolution.

Biology lesson:
If the population of tuskless elephants (which aren't attractive to the tusked elephants, hypothetically) are seperated, which they are in this scenario because tusked elephants don't like to mate with tuskless elephants (throwing H-W equilibrium out the window, nonrandom mating), the two populations of elephants will branch out, as mutations will show up in tuskless elephants that did not in tusked elephants, and vise versa. Eventually, after millions of years, two new species. Evolution.

Accually, elephants need thir tusks for dgging up roots and occtionally fighting.

I would like to bring up that some people belive human poaching is "Natural Selection" but debating over if man is part of nature or not is like debating which is better: Sprite or Seirra Mist. Its differnt from debating "Is that Natelie that visted aruba dead". It has nothing to do with logic, just opinion.

One more thing i'd like to ad, I would give up Coppertamias economy for wildlife anyway. poaching sucks.

The recessive genes in the remaing blue eyed people would continue to produce people with brown eyes....Whereas, with a psychopath event lasting a few decades maybe (at most) the browneye recessive gene would come through, so people would continue to have brown eyes.

This is totally irrelevant, but I have to nit-pick a tiny bit and note that blue, not brown, eyes are coded for by the recessive gene. If the world population was actually culled to the point of there being zero people with eye colors other than blue, there would never be another brown-eyed person unless a mutation occured to recreate that allele.

This is totally irrelevant, but I have to nit-pick a tiny bit and note that blue, not brown, eyes are coded for by the recessive gene. If the world population was actually culled to the point of there being zero people with eye colors other than blue, there would never be another brown-eyed person unless a mutation occured to recreate that allele.
Same goes for blue, though you'd need quite a bit of work and lots of punnet squares to be sure *shudder*.

Now, are we seeing evolution take place, or we just seeing natural selection take place?

*sigh* Go read a science textbook AND a logic textbook, please. and while you're at it, you may want to pick up a dictionary. :)


Out of curiosity, were you planning on giving any examples of scientific, logical, or etymological/verbal errors in my post? I'm under the impression that it was accurate on all three counts, but you're welcome to enlighten me if I'm mistaken.

This is totally irrelevant, but I have to nit-pick a tiny bit and note that blue, not brown, eyes are coded for by the recessive gene. If the world population was actually culled to the point of there being zero people with eye colors other than blue, there would never be another brown-eyed person unless a mutation occured to recreate that allele.

at least you understood my point that brown-eyed people would be wiped out in the psycho-scenario. :)

Now, are we seeing evolution take place, or we just seeing natural selection take place?
Pardon me while I go smash my head against the wall.

Out of curiosity, were you planning on giving any examples of scientific, logical, or etymological/verbal errors in my post? I'm under the impression that it was accurate on all three counts, but you're welcome to enlighten me if I'm mistaken.

maybe the problem here is with the definition of evolution. without going to a dictionary, i call evolution a genetic mutation that creates a characteristic more favorable to the environment.

in the case of the elephants, there are two characteristics--tusks or no tusks. no tusks is recessive. if the tusked elephants get wiped out, there hasn't been any mutation to adapt to the environment because the recessive gene already existed, so it's not really evolution. the classic example is with a particular species of moths in england. the white moths were the super-majority of the population because they could camaflauge (i can't spell... sue me) in the U.K.'s snow, but when england had its industrial revolution, the brown moths began to make up a majority of the population because they could better camaflauge (that spelling is really painful... sorry) in the soot. the moths didn't mutate to adapt to the environment, it's just the white ones ceased to have an advantage over the brown ones. when you have a portion of a species' population killed off by an environmental factor, there's no evolution taking place because there's no mutation involved. right?

Pardon me while I go smash my head against the wall.

Oh, by all means. Feel free.

I fail to see how a mutation must be involved for it to be evolution. Recall that we are talking about natural selection here, at the moment, which is the driving mechanism behind evolution.

Biology lesson:
If the population of tuskless elephants (which aren't attractive to the tusked elephants, hypothetically) are seperated, which they are in this scenario because tusked elephants don't like to mate with tuskless elephants (throwing H-W equilibrium out the window, nonrandom mating), the two populations of elephants will branch out, as mutations will show up in tuskless elephants that did not in tusked elephants, and vise versa. Eventually, after millions of years, two new species. Evolution.

H-W isn't applicable in real life anyway, so out the window, fine. Its not evolution coz being tuskless is already a possibility with alleles. Just coz tusked elephants may cease to exist (those alleles are lost through poaching) doesn't make the now solely tuskless elephants a new spp from the ones which were tuskless when tusked ones were about too. It means the gene pool has been diluted and elephants can't go back to having tusks without a mutation, and subsequent selection. For evolution, first you need to introduce/remove/change a gene and so have a new gene (or lack of) in hte gene pool, one which wasn't there before. then it must be selected for, which is unusual as most mutations will have negative effects and be selected against. now your selection is the driving force, but it needs a mutation. This is the first step to evolution. its a slow process coz positive mutations are rare, and you don't see it happening coz mutations only affect small things, they don't make you grow new arms (although i read somewhere that snakes have had a fair few macromutations gaining or losing vertibrae between different spp).

just read brain test and i think (s?)he explained it better than me.

And if I beat every brown dead horse, there will only be black and white ones left....

maybe the problem here is with the definition of evolution. without going to a dictionary, i call evolution a genetic mutation that creates a characteristic more favorable to the environment.

...when you have a portion of a species' population killed off by an environmental factor, there's no evolution taking place because there's no mutation involved. right?

Wrong, but that explains our misunderstanding. Evolution can be very simply defined as "biological change over time" - mutation is a means by which evolution may take place, but is not definitionally necessary. Just for fun, I pulled out a few of the biology textbooks from the bookshelf across the room for their definitions:

EVOLUTION:
1. "All the changes that transform life on Earth." - Campbell, Mitchell, Reece
2. "Genetic change in a line of descent over time, brought about by microevolutionary processes (natural selection, gene mutation, genetic drift, and gene flow)." - Starr, Taggart
3. "Any change in the relative frequencies of alleles in the gene pool of a population." - Miller, Levine

Hope that clears things up for you. :)

Now, are we seeing evolution take place, or we just seeing natural selection take place?

The situation at hand is natural selection. However, natural selection is the driving force behind evolution. In 50 to 100 years from now (probably a lot longer), if the current conditions continue (God forbid), we might be able to determine if the tuskless elephants have diverged from the mainstream tusked elephants into a new species (= Evolution). The point is that if poaching continues long enough and we wait long enough, we might be able to witness man-made evolution/speciation.

when you have a portion of a species' population killed off by an environmental factor, there's no evolution taking place because there's no mutation involved. right?

Evolution doesn't necessarilly need to be caused by mutations. The Galapagos Islands, for example, have many different species of birds that share a common ancestor. Their common ancestors didnt evolve into these different species through separate mutations, but by the natural selection caused by their different environments.

The situation at hand is natural selection. However, natural selection is the driving force behind evolution. In 50 to 100 years from now (probably a lot longer), if the current conditions continue (God forbid), we might be able to determine if the tuskless elephants have diverged from the mainstream tusked elephants into a new species (= Evolution). The point is that if poaching continues long enough and we wait long enough, we might be able to witness man-made evolution/speciation.

Alright, now is it possible for natural selection to occur and not lead to evolution? Are there are other factors that are needed for evolution to occur, such as geographical separation? If one genetic aspect of these elephants is wiped out and the species remains like it is only tuskless, would have evolution taken place?

Pardon me while I go smash my head against the wall.

Go ahead, knock yourself out.

If one genetic aspect of these elephants is wiped out and the species remains like it is only tuskless, would have evolution taken place?

Yes. See my post above defining evolution.

I was taught that Natural selection was when a gene is more favorable to a creature and ends up being passed on because it helps them out survive those with less favorable genes.

Since the tusk less ones are out surviving the ones with tusks and passing their genes on I'd say this is Natural Selection.

But I can't say it's evolution, not until the majority of the species has been altered.

Alright, now is it possible for natural selection to occur and not lead to evolution? Are there are other factors that are needed for evolution to occur, such as geographical separation? If one genetic aspect of these elephants is wiped out and the species remains like it is only tuskless, would have evolution taken place?

Yes

It's certainly not the best thing in the world for a species to be threatened, or changed because of indirect efforts, but why worry about elephants? We should worry about human activity that threatens our food supply, or human activity that lowers the wild fish count. Things like that, not elephants.

I was taught that Natural selection was when a gene is more favorable to a creature and ends up being passed on because it helps them out survive those with less favorable genes.

Since the tusk less ones are out surviving the ones with tusks and passing their genes on I'd say this is Natural Selection.

But I can't say it's evolution, not until the majority of the species has been altered.

Evolution doesn't require that the majority of a species be altered. It only requires change over time. Evolution doesn't mean the disappearance of the ancestor species either (hence why we have so many species.)

No ownder so many people don't believe in evolution. They have no idea what it is.

One more thing. It is certainly possible for mutations of the smaller-to-no tusk elephants to have larger tusks. It's not as if it's the end of the world right now. And if the survival of the world depended on large-tusk elephants, we could certainly encourage the population of larger-tusk elephants to increase, or genetically-graft the large-tusk gene onto "inferior" elephants. I don't see why people are getting so uptight about all of this.

Yes. See my post above defining evolution.

The reason for questioning I had, was that, were the pressure to be removed, the species would return directly to the state it had been in before.

But by your definition, that still fits for evolution. End of discussion.

my bad. thanks Poliwanacraca, you forced me to think rather than going on auto pilot and check my books. seems i was thinking about it too simplisticly. how embarasing, i study this at uni, i should know better :confused:

Didn't something like that happen with a certain Butterfly in England?
When they built a factory there (I assume it was in the Industrial Revolution) all the new Butterflies turned out to become dark over time, because there was so much black shit being blown into their area.
Then they later got rid of the pollution and now the Butterflies are Orange again.

I don't have a link, I heard it on TV once.

Didn't something like that happen with a certain Butterfly in England?
When they built a factory there (I assume it was in the Industrial Revolution) all the new Butterflies turned out to become dark over time, because there was so much black shit being blown into their area.
Then they later got rid of the pollution and now the Butterflies are Orange again.

I don't have a link, I heard it on TV once.

I think they were moths, and they were white with black splotches to blend in with birch tree bark, or something like that. As the white bark became black from pollution, those moths that were predominantly white were easy pickings for birds, while those that were predominantly black had a better defense.

-snip-
All Right.
Assuming that these moths have a very short life-span, wouldn't that then count for Natural Selection in action?
I wish they'd have done some study to show that more black moths were being born, or that there hadn't been black moths previously.

All Right.
Assuming that these moths have a very short life-span, wouldn't that then count for Natural Selection in action?


Yes. In fact, it's one of the most famous examples of natural selection in action.

my bad. thanks Poliwanacraca, you forced me to think rather than going on auto pilot...

Statements like this make me happy!

You're very welcome. :D

yeah, the peppered moths (Biston betularia)* are a famous example. i wouldn't have thought of it as evolution, but i guess by the definition given it could be. mind you, i've found things can always be difined differently in bio, and some things defy definiton :p . if you google them you'll prolly find plenty of sites on them.

the basic theory is that there's genetic variation within the spp, allowing darker and lighter varients. In polluted areas the lighter ones are easier for bird predators to spot, so dark is selected for, and vice-a-versa in cleaner areas. i can't remember if the dynamicness of the morphs is due to interbreeding, or if the other morphs genes are somehow stored in the moths.

*had to look it up

It's certainly not the best thing in the world for a species to be threatened, or changed because of indirect efforts, but why worry about elephants? We should worry about human activity that threatens our food supply, or human activity that lowers the wild fish count. Things like that, not elephants.


well, aside from my ethical disagreements with your statement, im pretty sure most ecosystems are far more complex then many people give them credit for. it is nearly impossible to predict the end results of removing just one species from an ecosystem, and often times those results are only apparent (and sometimes with rather unexpected results) once it is too late.

H-W isn't applicable in real life anyway, so out the window, fine. Its not evolution coz being tuskless is already a possibility with alleles. Just coz tusked elephants may cease to exist (those alleles are lost through poaching) doesn't make the now solely tuskless elephants a new spp from the ones which were tuskless when tusked ones were about too. It means the gene pool has been diluted and elephants can't go back to having tusks without a mutation, and subsequent selection. For evolution, first you need to introduce/remove/change a gene and so have a new gene (or lack of) in hte gene pool, one which wasn't there before. then it must be selected for, which is unusual as most mutations will have negative effects and be selected against. now your selection is the driving force, but it needs a mutation. This is the first step to evolution. its a slow process coz positive mutations are rare, and you don't see it happening coz mutations only affect small things, they don't make you grow new arms (although i read somewhere that snakes have had a fair few macromutations gaining or losing vertibrae between different spp).
H-W is applicable in the real world. We do it all of the time. You clearly have a very bad idea of what evolution is. If you have read my post, I was refering to the tuskless adapation as a method to create a pre-intercourse barrier to intraspecies mating, thus allowing sympatric speciation to occur in the future, as over time the small number of mutations (I said millions of years, though that was a bit of hyperbole) cause the two once similar populations to split into two species, hypothetically the tusked asian elephant and the tuskless asain elephant. This isn't difficult.

Alright, now is it possible for natural selection to occur and not lead to evolution?

I believe it is not possible to have natural selection to occur and have no evolution, unless the selection at question stops or other factors interfere.

Are there are other factors that are needed for evolution to occur, such as geographical separation?
These are the factors for Hardy-Weinburg Equilibrium:

1) The gene pool must be large
2) No migrations
3) Mating must be random
4) No mutations
5) No natural selection

When these 5 conditions are met, the gene frequences of a population (recessive and dominant) will remain stable at predictable ratios. If any of the following factors is false/unfulfilled, then HW Equilibrium is broken and evolution occurs.

If one genetic aspect of these elephants is wiped out and the species remains like it is only tuskless, would have evolution taken place?
It depends. Evolution/speciation occurs if the tusked elephants cannot mate and produce a fertile hybrid with a tuskless elephant. Assuming that these new elephants are completely lacking the tusk gene, and they cannot reproduce with the tusked elephants (genetically and biologically, since in this situation the tusked ones are already dead :eek: ), then evolution has occured.

well, aside from my ethical disagreements with your statement, im pretty sure most ecosystems are far more complex then many people give them credit for. it is nearly impossible to predict the end results of removing just one species from an ecosystem, and often times those results are only apparent (and sometimes with rather unexpected results) once it is too late.

Of course things are unpredictable. But elephants hardly have an effect on crop yields.

It depends. Evolution/speciation occurs if the tusked elephants cannot mate and produce a fertile hybrid with a tuskless elephant. Assuming that these new elephants are completely lacking the tusk gene, and they cannot reproduce with the tusked elephants (genetically and biologically, since in this situation the tusked ones are already dead :eek:), then evolution has occured.
*Technical quibble*

There can be other differences, say if the elephants are drastically different in genotype/phenotype, they would be considered different species. Determining the lines between species is highly difficult, not as some creationists would have us believe.

Of course things are unpredictable. But elephants hardly have an effect on crop yields.
Oddly enough, elephants are a key part of savannah grassland ecosystems (they kill the trees, leaving only the grass that are a vital part of the ecosystem). Removing the elephants has lead to parts of the savannah to be overrun by trees, destroying a very small biome.

H-W is applicable in the real world. We do it all of the time. You clearly have a very bad idea of what evolution is. If you have read my post, I was refering to the tuskless adapation as a method to create a pre-intercourse barrier to intraspecies mating, thus allowing sympatric speciation to occur in the future, as over time the small number of mutations (I said millions of years, though that was a bit of hyperbole) cause the two once similar populations to split into two species, hypothetically the tusked asian elephant and the tuskless asain elephant. This isn't difficult.

yes, my idea of evolution was off, see later post. HW can be done in labs, but there are 5 basic, and then some less basic ones.

1. Large population size

2. Random mating

3. No immigration, emigration

4. No selection

5. No mutation


We can assume there's no mutation, due to low mutation rate, but can't be sure. there's nothing we can do about selection, mating may not be random, generations may not be descrete. we may or may not be able to exclude immigration and emigration. The post is too far back for me to read while in the reply box, but if you assume that tusklessness does create a pre-intercourse barrier to intraspecies mating, tehn yes you are correct it would allow sympatric speciation.

edit: we're taught that HW is the boring condition where nothing's happening, but that this simply isn't the case out of our carefully controlled labs.

yes, my idea of evolution was off, see later post. HW can be done in labs, but there are 5 basic, and then some less basic ones.

1. Large population size

2. Random mating

3. No immigration, emigration

4. No selection

5. No mutation


We can assume there's no mutation, due to low mutation rate, but can't be sure. there's nothing we can do about selection, mating may not be random, generations may not be descrete. we may or may not be able to exclude immigration and emigration. The post is too far back for me to read while in the reply box, but if you assume that tusklessness does create a pre-intercourse barrier to intraspecies mating, tehn yes you are correct it would allow sympatric speciation.
I'm assuming that it does because of preference for tusked males (outside of china) and the preference for tuskless males (in china).

then yeah.

just to add another voice to the whole ecosystem argument, here i am. not a very useful voice it seems, but hopefully i'll learn.

The elephants-trample-savannah-trees was interesting. But to be realistic, people could easily use artificial means to do the same effect.

The elephants-trample-savannah-trees was interesting. But to be realistic, people could easily use artificial means to do the same effect.
Yes, let's just throw money at the problem instead of using the system nature gives us.

This is sad... Tusks do not make a species. Look at cows. Just because some don't have horns doesn't mean they're a different species! :( So this is what the world is coming to.

Yes, let's just throw money at the problem instead of using the system nature gives us.
Apart from the matter that I think there is another, more intrinsic value in having elephants around.
I like Elephants and Whales and Dolphins and all the rest of it.
Even if they didn't have any economic value, I still don't see why you wouldn't want to preserve them, and if it is only to be able to show your kids an elephant one day.

Of course things are unpredictable. But elephants hardly have an effect on crop yields.


i like elephants, but ive never really studied them, let alone their interactions/impacts on ecosystems. although there may not be a direct link to elephants and crops, there is very likely some indirect link twixt elephants and something else in the ecosystem that is beneficial to us.

i have no clue what it is, and i doubt many people do until too late. recently read an example where all kinds of screwups on some island nation were linked to the extermination of macro-preditors (like jaquars and such) cant remember the whole chain of events, and it was rather convoluted, but it led to pretty much a complete and drastic change in the ecosystem.
it was in 'the third chimpanzee' by jared diamond. good book, i just cant remember the specifics of the example right now.

*Technical quibble*

There can be other differences, say if the elephants are drastically different in genotype/phenotype, they would be considered different species. Determining the lines between species is highly difficult, not as some creationists would have us believe.

Exactly. Evolution is a slow process. There is speculation of sudden drastic mutations leading to new species. In general, evolution is a gradual, fluid process that involves minute change over time. "Species" is a man made idea created to help us organize the animal kingdom for our own study.

Meanwhile, in Vatican City...

Swiss Guard: Your holiness! Its the elephants sir! They're evolving!
Pope: Ach! Zer Elephantz vill pay for zis betrheyal! SEND ZEM TO DER CAMPZ!
Swiss Guard: We dont have any camps Your Holiness, I mean, our entire country is a few miles wide, were the smallest country on the planet.
Pope: Blazt eet! Build szome camps! And dont let zer Italian government know about eet!
Swiss Guard: They already know...
Pope: Ach! Zer are spies in mien palace! KILL ZEM ALL!
Swiss Guard: No, your Holiness, they heard you yelling, see, theres a police officer over there.
Pope: Arrest heem! Do not let zee traitor geet away!
Swiss Guard: I cant really...I mean, I get laughed at enough as is, hint hint.
Pope: No, I like zer uniforms. Zey are cool!
Swiss Guard: We had better uniforms a hundred years ago.
Pope: Too bad! Arrest ze polize officar!

I certainly hope I'm not the only one who doesn't find this funny. You're a sick puppy, wee one!

are you serious? assuming your information is correct, the de-tusked elephants didn't evolve from tusked elephants to adapt to people killing them off--it's just a recessive gene that already exists. if everyone with brown eyes were murdered by a hitler-like psychopath, the remaining blue eyed people would not have evolved from the brown eyed people, nor would their children. it would just be that all of the brown eyed people would be dead. that's not evolution.

You just described an example of natural selection, but which would not lead to a survival improvement of the race. On long run, blue eyes peoples would multiply and take the place left by brown eyes peoples.

Natural selection come from a new born specimen with an anomaly which help him survive in the nature. This new improved specimen and is descent will have better chance surviving in the nature, so in the long run they will take the place of other specimen how live in the same ecosystem.

The recessive genes in the remaing blue eyed people would continue to produce people with brown eyes.

Blue and green are recessive genes for human eyes (brown is dominant), which mean the person must have 2 blues genes (one from each parent) or 2 greens eyes genes to actually have blue/green eyes. Therefore, two blue eyes parent will always produce blue eyes kids

Wrong, but that explains our misunderstanding. Evolution can be very simply defined as "biological change over time" - mutation is a means by which evolution may take place, but is not definitionally necessary. Just for fun, I pulled out a few of the biology textbooks from the bookshelf across the room for their definitions:

EVOLUTION:
1. "All the changes that transform life on Earth." - Campbell, Mitchell, Reece
2. "Genetic change in a line of descent over time, brought about by microevolutionary processes (natural selection, gene mutation, genetic drift, and gene flow)." - Starr, Taggart
3. "Any change in the relative frequencies of alleles in the gene pool of a population." - Miller, Levine

Hope that clears things up for you. :)

see, i was too lazy to do this :)

maybe the problem here is with the definition of evolution. without going to a dictionary, i call evolution a genetic mutation that creates a characteristic more favorable to the environment.

in the case of the elephants, there are two characteristics--tusks or no tusks. no tusks is recessive. if the tusked elephants get wiped out, there hasn't been any mutation to adapt to the environment because the recessive gene already existed, so it's not really evolution. the classic example is with a particular species of moths in england. the white moths were the super-majority of the population because they could camaflauge (i can't spell... sue me) in the U.K.'s snow, but when england had its industrial revolution, the brown moths began to make up a majority of the population because they could better camaflauge (that spelling is really painful... sorry) in the soot. the moths didn't mutate to adapt to the environment, it's just the white ones ceased to have an advantage over the brown ones. when you have a portion of a species' population killed off by an environmental factor, there's no evolution taking place because there's no mutation involved. right?

Sorry, but your definition of evolution is incorrect. The previous poster was correct in every term he used.

What you have described in the moths is natural selection, which is the action of evolution. You seem to overlook the fact that the mutation may have happened centuries before the environment changed. Nowhere in the theory of evolution does it say that creatures (genes) mutate to adapt to the environment. Genes have no knowledge of the environment so how can they adapt to it? The action of natural selection simply selects those genes already in the genepool that are most suited for the environment.

If the elephants have 2 genes, 1 for tusked and one for tuskless, how do you know one of them is not a mutation?

Why are you all still having this argument, it was over ages ago.

Why are you all still having this argument, it was over ages ago.

Because people keep bumping it when they have nothing to add to the argument either way?

Because people keep bumping it when they have nothing to add to the argument either way?

Nah that cant be it, maybe its people bumping it up further when they have nothing to add to the so called "argument" either ;)

are you serious? assuming your information is correct, the de-tusked elephants didn't evolve from tusked elephants to adapt to people killing them off--it's just a recessive gene that already exists. if everyone with brown eyes were murdered by a hitler-like psychopath, the remaining blue eyed people would not have evolved from the brown eyed people, nor would their children. it would just be that all of the brown eyed people would be dead. that's not evolution.

That's exactly the mechanism that evolution uses.

If tigers eat yaks then the smallest, weakest, and thinnest skinned yaks get eaten. All the small and weak yaks are dead, so those that remain get bigger.

Then all the small and weak tigers starve, so only the bigger tigers, with stronger teeth remain, so those that remain get bigger.

Then the yaks do the same again.

Then the tigers.

Then you end up with Saber tooth tigers and Titanotheres. Eventually they both go extinct because they get too big to be supported by their ecosystem.

Same deal.
Ivory Poachers kill elephants with tusks. The only trait that helps them avoid getting killed is not having tusks. Then Ivory poachers will go extinct because the ecosystem won't support their trade.

That's exactly the mechanism that evolution uses.
Then you end up with Saber tooth tigers and Titanotheres. Eventually they both go extinct because they get too big to be supported by their ecosystem.


well, there's a balance between lots of things here, so they're not likely to go extinct coz of this arms race.