Hitchens and "failed" species

[Tumblehome]

Christopher Hitchens, in his debate with Al Sharpton, says over 98.9 percent of species that ever existed on Earth are now extinct. I've heard that figure before as an argument against design: If all those species no longer exist, how could life be designed by a perfect creator?

But it occurred to me that the figure of 98.9 percent might be misleading. I've always assumed it to mean species that died out and left no descendants, like the dodo bird. But does it also include species like homo erectus which didn't really die out but evolved into another species. It seems to me that they can't be considered "failed" since they successfully evolved into subsequent species.

Maybe that wouldn't alter the figure by much, and even if it did, it wouldn't affect the argument. But I wouldn't want to see a misleading figure in an argument against design.

So, is it a misleading figure?

[Mobyseven]

Well, if everyone accepts that homo erectus evolved, that pretty much puts the evolution/creationism case to bed right there.

Having said that, I don't know the answer to your question. I would be interested to know, but I don't think it particularly matters either way.

ETA: Actually, on a second thought I would say that including homo erectus would be perfectly fine (as a 'failed' species). After all, it wasn't that all homo erectus evolved into homo sapiens. Instead, homo sapiens evolved and displaced homo erectus - in comparison, homo erectus is a failed species.

[clerihew80]

The actual figure is 99.9%

[Mr. Scott]

Christopher Hitchens, in his debate with Al Sharpton, says over 98.9 percent of species that ever existed on Earth are now extinct. I've heard that figure before as an argument against design: If all those species no longer exist, how could life be designed by a perfect creator?

But it occurred to me that the figure of 98.9 percent might be misleading. I've always assumed it to mean species that died out and left no descendants, like the dodo bird. But does it also include species like homo erectus which didn't really die out but evolved into another species. It seems to me that they can't be considered "failed" since they successfully evolved into subsequent species.

Maybe that wouldn't alter the figure by much, and even if it did, it wouldn't affect the argument. But I wouldn't want to see a misleading figure in an argument against design.

So, is it a misleading figure?

I'm not sure if it is a semantic issue, but there seems to be an asumption about what "evolves into" means and implies. Does it make a difference, when a species goes extinct, if an individual from that species mutated into a different species before the extinction?

Case 1: A species goes extinct leaving no descendents.
Case 2: A parent species has one individual which mutates into a child species before the parent species goes extinct.

In case #2, does the word "extinct" still apply? My guess is that it does, even in the case where an individual mutated into another species before the extinction occurred. Either way, a species goes "extinct."

From Wiki as per Google: "In biology and ecology, extinction is the ceasing of existence of a species or group of taxons. The moment of extinction is generally considered to be the death of the last individual of that species. Extinction is a natural phenomenon; it is estimated that 99.9% of all species that have ever lived are now extinct"

[Tumblehome]

ETA: Actually, on a second thought I would say that including homo erectus would be perfectly fine (as a 'failed' species). After all, it wasn't that all homo erectus evolved into homo sapiens. Instead, homo sapiens evolved and displaced homo erectus - in comparison, homo erectus is a failed species.


Case 2: A parent species has one individual which mutates into a child species before the parent species goes extinct.

In case #2, does the word "extinct" still apply? My guess is that it does, even in the case where an individual mutated into another species before the extinction occurred. Either way, a species goes "extinct."


Okay, I suppose that technically, it is extinct, but I guess my problem is with calling it "failed". If the one individual is a new species, how does it procreate? It must mate with others of the parent species so that the original species is continued in some way, just not in its wholly complete form. Without the old species, the new improved species would never get off the ground. In that way, can't it be said that the parent species has not failed, but has successfully changed for the better?


Well, if everyone accepts that homo erectus evolved, that pretty much puts the evolution/creationism case to bed right there.


You mean it hasn't been settled yet? ;)

[Tumblehome]

The actual figure is 99.9%


I'm pretty sure Hitchens said 98.9. I listened to it twice, though I didn't bookmark the video to check it again. As much as I agree with him, I'll accept Wiki's--and your--figure over his. :)

[Mobyseven]

It is still a 'failed' species because it has been displaced by another species.

That the species that displaced it evolved from it is irrelevant, really. If anything it highlights that there were adaptations in the newer species that the older species didn't have, and that were beneficial.

[Mojo]

If the one individual is a new species, how does it procreate?


Well, this isn't how evolution occurs: the changes are gradual: you don't suddenly get an individual born which is recognisably of a different species to its parents, or unable to breed with the rest of the population.

An example of this sort of thing are ring species (http://en.wikipedia.org/wiki/Ring_species). You have a population, each part of which is capable of interbreeding with its neighbours, but with individuals at opposite ends of the range that cannot interbreed. Now imagine the same thing across time rather than space, and you have an illustration of how evolution occurs.

[Normal Dude]

It also helps to define what concept of species we are talking about; ask different people from different professions what a species is, and they will often give you different answers.

[clerihew80]

I'm pretty sure Hitchens said 98.9. I listened to it twice, though I didn't bookmark the video to check it again. As much as I agree with him, I'll accept Wiki's--and your--figure over his. :)
Sorry to be picky, but when you're talking about tens of millions of species, one percent does make a difference. Anyway, I've heard the 99.9% statistic from several different sources, so I assume it's the commonly accepted estimate.

[Tumblehome]

Well, this isn't how evolution occurs: the changes are gradual: you don't suddenly get an individual born which is recognisably of a different species to its parents, or unable to breed with the rest of the population.

An example of this sort of thing are ring species (http://en.wikipedia.org/wiki/Ring_species). You have a population, each part of which is capable of interbreeding with its neighbours, but with individuals at opposite ends of the range that cannot interbreed. Now imagine the same thing across time rather than space, and you have an illustration of how evolution occurs.


Yes, I was continuing Mr. Scott's "case 2" example, which I assume he was simplifying for brevity.

A species has two possible end results: It will die out as a dead end with no descendent species, or it will die out with a descendent species having evolved from it. Both end in extinction for the original species, but the first case is a failure because that particular gene pool ceases to exist in any way. In the second case, the gene pool continues to exist with a slight modification. Since that is the best possible result available for the original species, it didn't fail, but successfully evolved.

Using myself as an analogy (which might not be applicable, but I'll give it a shot): There are two possible end results for me. I'll die without producing any offspring, or I'll die leaving offspring behind. Both result in my extinction, but in the first case, my genetic makeup comes to a dead end and ceases to exist. In the second case, my genes are carried on by my offspring. Since that is the best result availbable for my genes, it is not considered a failure. I have successfully done my job biologically.

Why don't we look at the evolution the same way?

[Tumblehome]

Sorry to be picky, but when you're talking about tens of millions of species, one percent does make a difference. Anyway, I've heard the 99.9% statistic from several different sources, so I assume it's the commonly accepted estimate.


No problem. I wasn't disputing your figure, just relating what Hitchens said, or what I thought he said. The 99.9 percent estimate sounds like the correct one.

[Tumblehome]

It also helps to define what concept of species we are talking about; ask different people from different professions what a species is, and they will often give you different answers.


That might be a subject for another thread. For this thread, I think the broad, generally-accepted concept of "species" is good enough. It is for me, at least. :)

[Mojo]

A species has two possible end results: It will die out as a dead end with no descendent species, or it will die out with a descendent species having evolved from it. Both end in extinction for the original species, but the first case is a failure because that particular gene pool ceases to exist in any way. In the second case, the gene pool continues to exist with a slight modification. Since that is the best possible result available for the original species, it didn't fail, but successfully evolved.

Using myself as an analogy (which might not be applicable, but I'll give it a shot): There are two possible end results for me. I'll die without producing any offspring, or I'll die leaving offspring behind. Both result in my extinction, but in the first case, my genetic makeup comes to a dead end and ceases to exist. In the second case, my genes are carried on by my offspring. Since that is the best result availbable for my genes, it is not considered a failure. I have successfully done my job biologically.


A better analogy might be the situation if you leave offspring behind, but your siblings don't. Some of your siblings' genes will be passed on, but not as many as if they had offspring of their own. A new species is likely to arise from a sub-population of a species, and coexist with the species from which it arose at some point even if it eventually replaces it. There are always likely to be members (and even populations) of the old species which, if the new species replaces the old one, will not have any descendants.

[scratchy]

Life on earth has gone through several extinction episodes, at least one with over 90 % of all species being wiped out. Add to that all species that has disappeared at other times without evolving, then that figure doesnt seem unreasonable.

[JoeTheJuggler]

I don't like the term "failed" species because it sounds like an evaluation.

Many species of dinosaurs were well adapted to their various niches for a very long time--much longer than many species alive today (humans for instance). How can you call the one a success and the other a failure? We already have a word for species that are no longer alive: extinct.

[Tumblehome]

A better analogy might be the situation if you leave offspring behind, but your siblings don't. Some of your siblings' genes will be passed on, but not as many as if they had offspring of their own. A new species is likely to arise from a sub-population of a species, and coexist with the species from which it arose at some point even if it eventually replaces it. There are always likely to be members (and even populations) of the old species which, if the new species replaces the old one, will not have any descendants.


But still, a good chunk of the original species' gene pool has been continued, which is "better" than it ceasing to exist altogether from the standpoint of the species. The same as continuing my genes through my offspring.

[Tumblehome]

Life on earth has gone through several extinction episodes, at least one with over 90 % of all species being wiped out. Add to that all species that has disappeared at other times without evolving, then that figure doesnt seem unreasonable.


Agreed.

[Tumblehome]

I don't like the term "failed" species...


Yay! :)


...because it sounds like an evaluation.


Aww. :(

But we evaluate our own individual existence by whether or not we pass on our genes. Why not the same with species?


Many species of dinosaurs were well adapted to their various niches for a very long time--much longer than many species alive today (humans for instance). How can you call the one a success and the other a failure? We already have a word for species that are no longer alive: extinct.


Since all species end up extinct anyway, extinction in itself is not a measure of failure. Success or failure depends on how much of the gene pool is continued after the species is extinct.

[Mojo]

But we evaluate our own individual existence by whether or not we pass on our genes.


Do we?

[JoeTheJuggler]

Since all species end up extinct anyway, extinction in itself is not a measure of failure. Success or failure depends on how much of the gene pool is continued after the species is extinct.
Do all species go extinct? I think that's far from a given. There's still plenty archaebacteria around.

How is passing on a portion of the gene pool a "success" for the species if the species is gone?

Sounds like success or failure for the selfish genes, and that's not what the OP was about, right?

[Mobyseven]

But we evaluate our own individual existence by whether or not we pass on our genes. Why not the same with species?

Er...if the species is displaced by a new species that evolved from it, then the genes of the new species are sufficiently different to be, well...a new species.

The genes may have been passed on, but over time they have changed enough for speciation to occur. The original genes (well, some of them) are not even there anymore. If we are using 'passing on genes' as an example then no species in the history of the earth has ever failed, as it would have had genes in common with a 'successful' species of the time.

[Roboramma]

I agree that it's misleading. Saying that 99.9% of species that ever lived are now extinct, if we're including species that are ancestral to now existent species, basically all that's being said is, "Most of the organisms that have ever lived are dead."
Well, obviously.

Nothing stops evolving, so given a few million years, more or less, (and much less for organisms with faster reproductive times) you're almost certain to have a new species, if for no other reason than genetic drift. If that's all that's being said, it's not really very interesting. At least not in the context of Hitchen's remarks.

On the other hand, what percentage of species that have ever lived are not now existent or ancestral to one or more now existent species? Probably a much more difficult question to answer.

I wonder if the answer is very much different, however.

I think basically the problem that I have with the statement is that when you talk about extinct species, must of us think of species going extinct. That didn't necessarily happen to homo erectus. If there's a continuous line of decent, then a species can be extinct without an extinction event.
And personally, it's only such extinction events that seem to have bearing on the point that Hitchens was making. Or that most people make when they bring up the "99.9% extinct" figure.
Mind you, I think his point still stands, even if the figure for the value that I think is important is much smaller.

[latent aaaack]

Life on earth has gone through several extinction episodes, at least one with over 90 % of all species being wiped out. Add to that all species that has disappeared at other times without evolving, then that figure doesnt seem unreasonable.

That figure represents 90% of all species that existed only at those times. Those extinctions were followed by massive increases in biodiversity so that 90% may only translate into a fraction of total species that ever lived. But certainly the arguement as a whole is valid since it's known that massive numbers of species, whether 10% or 50%, or all life on earth can go extinct from supposedly lovingly intelligently designed natural forces.

[Tumblehome]

Do we?


I mean that we have determined that the purpose of an organism is to reproduce. At least, that's what I learned in elementary school.


Do all species go extinct? I think that's far from a given. There's still plenty archaebacteria around.


Are the archaebacteria still in their original forms? Have they not evolved at all? (This isn't a rhetorical question; I really don't know, though I suspect they must have changed somehow in 3.5 billion years.)


How is passing on a portion of the gene pool a "success" for the species if the species is gone?


I'd say it's more successful than a species meeting a dead end and not having any of its genes in a subsequent species, especially when the only options are "evolve into another species or die out as a dead end".


Er...if the species is displaced by a new species that evolved from it, then the genes of the new species are sufficiently different to be, well...a new species.

The genes may have been passed on, but over time they have changed enough for speciation to occur. The original genes (well, some of them) are not even there anymore. If we are using 'passing on genes' as an example then no species in the history of the earth has ever failed, as it would have had genes in common with a 'successful' species of the time.


Just having genes in common with succesful species doesn't matter. It's whether or not they're passed on to a subsequent species. That's why I would call the dodo a failed species, but not homo erectus because out of it came a new species with the vast majority of its genes.


I agree that it's misleading. Saying that 99.9% of species that ever lived are now extinct, if we're including species that are ancestral to now existent species, basically all that's being said is, "Most of the organisms that have ever lived are dead."
Well, obviously.

Nothing stops evolving, so given a few million years, more or less, (and much less for organisms with faster reproductive times) you're almost certain to have a new species, if for no other reason than genetic drift. If that's all that's being said, it's not really very interesting. At least not in the context of Hitchen's remarks.

On the other hand, what percentage of species that have ever lived are not now existent or ancestral to one or more now existent species? Probably a much more difficult question to answer.

I wonder if the answer is very much different, however.

I think basically the problem that I have with the statement is that when you talk about extinct species, must of us think of species going extinct. That didn't necessarily happen to homo erectus. If there's a continuous line of decent, then a species can be extinct without an extinction event.
And personally, it's only such extinction events that seem to have bearing on the point that Hitchens was making. Or that most people make when they bring up the "99.9% extinct" figure.
Mind you, I think his point still stands, even if the figure for the value that I think is important is much smaller.


So I'm not a lone voice in the wilderness. :)

Good point about genetic drift. If a species can't help but evolve even when there's no environmental pressure to do so, evolving can hardly be considered a failure.

[Mobyseven]

Really then, this comes down to a discussion of semantics - nothing wrong with that of course.

I suppose the important thing is simply to define what one considers a 'failed species' when the term is used - personally while I understand your definition, it doesn't sit right with me. At the moment I can't think of a better definition though - if I think of one I'll post it here.

I'd say that the percentage is going to very, very high regardless of the specific definition used though...

[Tumblehome]

It isn't the most vital of topics, and even though I agree that the percentage would probably still be high, I think the 99.9 percent figure could still be used in the argument agaist design, since all those species are extinct, after all.

I just don't like the term "failed" in the case where a species evolves into another. Extinct, yes of course, but not failed. For a species to stay alive long enough to evolve doesn't strike me as a failure.

If you come up with a definition, I'd like to hear it.

[Mobyseven]

The best definition I can come up with is: A species that has gone extinct, for whatever cause, or a species that results from the interbreeding of other species but that is itself infertile.

I know that this is different from how we have been using it up to now, and that this is in fact broader. It is really a difference of how we rate the word 'failure' - personally I don't see failure as a negative thing, rather an inevitable thing. If a species is no longer with us then at some stage it either failed to adjust to new living conditions or it was displaced by a more successful species. Either way constitutes a failure of sorts - the end of a species - and rather than see that as a bad thing I see it more as a testament to an ever-evolving world.

I included the second category (e.g. Mules) simply because even though they are not extinct, they are incapable of breeding among themselves and so are incapable of passing on any of their genes to a new generation. They are, in a very real sense, living failures.

But as I said, the most important thing to do is to define how we are using the word. I would imagine that for most people the definition would lie somewhere in between our two definitions. Either way, people will be able to grasp what you are talking about - it is only if you wish to get into the minutia that it really becomes necessary to define.

[Tumblehome]

If a species is no longer with us then at some stage it either failed to adjust to new living conditions or it was displaced by a more successful species.


But doesn't a species adjust to new living conditions by evolving to a new species? (That is, the new living conditions determine that only those with gene X will survive. And consider that gene X was already in place in some of the old species before conditions changed.)

We owe our existence to an unbroken chain of species going back through erectus and australopithecus and the first mammal, all the way back to the first bacterium. Every single species in that chain "succeded" in evolving to another species when it couldn't handle changing conditions. If there was a single break anywhere in that chain, we wouldn't be here today. On the other hand, there isn't a single organism today that owes its existence to the dodo or neandertal, or any species that "failed" to evolve.


Either way constitutes a failure of sorts - the end of a species - and rather than see that as a bad thing I see it more as a testament to an ever-evolving world.


Why call it failure, then? It might be just semantics, but semantically-speaking, I think it's fairly important. Other than that, I think we agree.

[latent aaaack]

wrong thread

[Mobyseven]

But doesn't a species adjust to new living conditions by evolving to a new species? (That is, the new living conditions determine that only those with gene X will survive. And consider that gene X was already in place in some of the old species before conditions changed.)

We owe our existence to an unbroken chain of species going back through erectus and australopithecus and the first mammal, all the way back to the first bacterium. Every single species in that chain "succeded" in evolving to another species when it couldn't handle changing conditions. If there was a single break anywhere in that chain, we wouldn't be here today. On the other hand, there isn't a single organism today that owes its existence to the dodo or neandertal, or any species that "failed" to evolve.

That description sounds a little bit Lamarckian for my liking - species don't adjust to new conditions by evolving, new conditions create an environment where certain variations (and eventually different species) are better adapted than the 'old' species.

Certainly there are members of that species that were successful in passing on their genes, and so eventually 'evolving', but on the group level (where we can reasonably talk about different species) they are a failure - the group, or species, has failed in the new set of conditions, and so is displaced or dies out.

Your definition would make more sense (to me at least) were we to focus on genes rather than species - then the successful genes would be the ones that are passed on generation to generation.

Why call it failure, then? It might be just semantics, but semantically-speaking, I think it's fairly important. Other than that, I think we agree.

Good question. I suppose it is because I see the species as being successful on two conditions: The species must survive, and the species must pass on its genes to a new generation. In comparison, a gene is successful on only one condition: That it is passed onto a new generation.

But yes, aside from that, we agree.