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. 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. 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?