Hitchens and "failed" species

[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.