A new study on natural selection and speciation

[micatala]

Here is a new study, indicating that natural selection is likely the major driver in speciation.

http://www.sciencedaily.com/releases/20 ... 090021.htm

It says in part:

The new study, published online in the Proceedings of the National Academy of Sciences, provides empirical support for the proposition that natural selection is a general force behind the formation of new species by analyzing the relationship between natural selection and the ability to interbreed in hundreds of different organisms – ranging from plants through insects, fish, frogs and birds – and finding that the overall link between them is positive.

. . . . . . .

The specific question that Funk and his colleagues set out to answer is whether there is a positive link between the degree of adaptation to different environments by closely related groups (termed ecological divergence) and the extent to which they can interbreed (termed reproductive isolation.)

. . . . .


Eliminating the time factor. The results of previous speciation studies have been clouded by the effects of time. Regardless of the role that natural selection plays, random mutations are bound to increase the reproductive isolation between two groups over time. In earlier studies, it has been difficult – if not impossible – to disentangle the two effects. With the proposed approach, however, the authors could apply a widely used mathematical procedure, called regression analysis, to factor out time's effects and isolate the impact of natural selection.

Of course, this is only one study, so I don't want to draw overblown conclusions. I also know this is not a totally new approach and that to the 'experts' this might be old hat.

However, it does seem to lend additional support to the notion of natural selection as a powerful force in speciation.

It also seems to show that mutations, while still important, are less essential in speciation than previously thought. Given that creationists often attack mutations as being incapable of giving rise to 'viable' new species, this study might have the effect of providing ammunition against this creationist argument.

So, the first question for debate is:

To what extent does this study and the related ones quoted in the article make it easier to refute the claims of creationists that evolution, and in particular natural selection, is not capable of producing new species?

Now, some creationists might accept 'small speciation events' but not what they would call 'macroevolution', e.g. populations of primates evolving into human beings.

Does this study provide a mechanism by which this objection can be more readily refuted?

[juliod]

Now, some creationists might accept 'small speciation events' but not what they would call 'macroevolution', e.g. populations of primates evolving into human beings.

I can see it now. Creationists insisting that there is "microspeciation" and "macrospeciation" which never occors.

I don't think the study you mentioned will make any difference to creationists. If I understadn it right, they are studying the difference between "time" (the accumulation of random mutations) and natural selection (the differentiation between mutants carrying those mutations). It's an interesting question, but not one that will impress someone who denies the reality of mutation and selection.

DanZ

[Bro Dave]

As one who believes in guided evolution, I hope not to be on the receiving end of the brick bats aimed at the "Creationists". However, the textbook explaination of evolution just does not wash for me. Everywhere I look, I see something that tells me there were intelligent decisions made on the basis of specific needs. As an example, that the eustation tube in the ear, that equalizes the pressure accross the eardrum. An accident? Really! And, this "accident" appears,(as far as I know) everywhere there are ears! But that's only one example. The patterns that work are copied cross species, and adapted to meet specific need. Usually, these refinements are not a matter of life or death, but just make life a little more pleasent. So, how does the feedback work for "pushing genetic accidents" in that direction?

Religionist use God as a "magic wand" to make it all work, but scientists are really is no different. They use the TIME wand, waving it furiously whenever challanged on an evolutionary outcome.(given enough time, anything is not only possible, but probably... )

So, what exactly is so repugnent about a guided evolution? The existance of intelligence is certainly not in dispute. So why is it sooo important to not have a Creator/Designer/Implimentor making it all come together? While it is not possible to absolutely prove or disprove the existance of such a Creator, there appear to be "fingerprint" all around us suggesting it ain't just an accident!

Bro Dave

[QED]

I can see lots of scope for driving this way off-topic. Let's see if we can stick to micatala's question...

To what extent does this study and the related ones quoted in the article make it easier to refute the claims of creationists that evolution, and in particular natural selection, is not capable of producing new species?

Now, some creationists might accept 'small speciation events' but not what they would call 'macroevolution', e.g. populations of primates evolving into human beings.

Does this study provide a mechanism by which this objection can be more readily refuted?

Dave, I'm going to start another topic to pick-up your point. Anyone else wishing to respond should do so here...
Does evolution need a guiding hand?

[Jose]

It also seems to show that mutations, while still important, are less essential in speciation than previously thought. Given that creationists often attack mutations as being incapable of giving rise to 'viable' new species, this study might have the effect of providing ammunition against this creationist argument.

As a geneticist, I must argue that the only source of genetic variation is mutation. Once mutations have occurred, creating new genetic variants, those variations can be mixed and matched with others by meiotic recombination (at least in sexually-reproducing species). Therefore, it is wholly impossible to have evolution or natural selection without mutation. Without mutation, there can be no new alleles, and no genetic variation. No variation, nothing for selection to select among.

I make this point because it seems to be so easily overlooked, probably because many people have an understanding of "mutation" that is, shall we say, incomplete.

Creationists take advantage of this in saying that mutation cannot create new species. Mutations create genetic variants within a species. In time (yes, Bro, time)--a few, or many generations--one population of a species may have genetic variations fixed in it that are different from those of a different population of that species. When those different variations result in failure to interbreed, then we've got speciation. So, mutation alone is insufficient. So, of course, is selection (or drift, or any other mechanism of differential reproduction). Both are needed. In my view, it makes no sense to argue whether one, alone, is responsible--or to claim that since one, alone, is insufficient, evolution is nullified. Both are needed. Both occur.

To what extent does this study and the related ones quoted in the article make it easier to refute the claims of creationists that evolution, and in particular natural selection, is not capable of producing new species?

The article is, essentially, saying that existing variation in a population can be exploited by selection. This is the same as it has always been. Whether new species arise depends entirely on which genes the variation is in. Some can achieve speciation. Some can't.

Now, some creationists might accept 'small speciation events' but not what they would call 'macroevolution', e.g. populations of primates evolving into human beings.

Ah, but apes evolving into humans is microevolution. It should, therefore, be fully acceptable.

Does this study provide a mechanism by which this objection can be more readily refuted?

I doubt it. They are trying to disentangle time from selection itself--tricky, because selection by definition requires multiple generations to occur. Again, I fear we are up against the complexity of the science, which many people won't be interested in studying deeply.[/quote]