# Speciation and fruit flies



## Dan....

Has the following supposed instance of speciation ben refuted?



> http://www.talkorigins.org/faqs/faq-speciation.html
> 
> Dobzhansky and Pavlovsky (1971) reported a speciation event that occurred in a laboratory culture of Drosophila paulistorum sometime between 1958 and 1963. The culture was descended from a single inseminated female that was captured in the Llanos of Colombia. In 1958 this strain produced fertile hybrids when crossed with conspecifics of different strains from Orinocan. From 1963 onward crosses with Orinocan strains produced only sterile males. Initially no assortative mating or behavioral isolation was seen between the Llanos strain and the Orinocan strains. Later on Dobzhansky produced assortative mating (Dobzhansky 1972).



Another source...



> http://www.rtis.com/nat/user/elsberry/evobio/evc/wre_arch/wre00029.htm
> 
> For example, Theodosius Dobzhansky and
> Olga Pavlovsky reported(13) in 1971 that a strain of fruit flies they
> collected in Colombia was at first fully interfertile with a strain
> collected in the Orinoco Basin. They kept the two stocks separate for
> about five years, and then crossed them again. This time the male offspring
> were completely sterile. A substantial amount of genetic isolation
> had developed in only five years.



Then I read, on a forum (which of course is not a credible source) -



> http://www.iscid.org/boards/ubb-get_topic-f-6-t-000589-p-4.html
> 
> The Darwinians stopped testing their own naive hypothesis when Dobzhansky last failed to produce species through the most intensive selection with Drosophila. Furthermore, much to his credit he admitted his failure.



...the poster who said this did not cite a source.


*****
So now my question:


Is it true that Dobzhansky was able to speciate a strain of fruit flies that was notable to mix with another strain and produce fertile offspring and hence must be classified as a new species?

IF not, then what souces can be sited that show other wise?


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## Dagmire

What that proves is that intelligence is needed to create something or alter that creation.


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## cih1355

It was never shown that fruit flies can reproduce outside of their own kind. There can be a variety of fruit flies, but fruit flies will not produce a non-fruit fly.


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## Dan....

> It was never shown that fruit flies can reproduce outside of their own kind. There can be a variety of fruit flies, but fruit flies will not produce a non-fruit fly.



It's not the point of the naturalists to have the fruit fly to produce a non-fruit fly. Their point is to show that macro-evolution (evolution at or above the level of species) is possible, or even probable; that macro-evolution is made up of a series of micro-evolutional steps that ends with a new species.

If these two strains of fruit flies were able to mate and produce a fertile offspring, then they are the same species by definition. This they claimed to occur at the begining of their test in 1958. Two strains were able to mate to produce a hybrid fruit fly.

However, 5 years later they attempted to mate the direct offspring of both strains of fruit flies and found them to produce infertal males. In other words, these fruit flies would no longer be the same species as they cannot mate to produce a fertile offspring. In essence we have two strains of fruit flies, being able to reproduce and hence of the same species, that split into two separate species of fruit fly.


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## SRoper

Dagmire said:


> What that proves is that intelligence is needed to create something or alter that creation.



No it proves that intelligence _can_ alter creation, not the necessity of intelligence to alter creation.

If the claims hold up it also proves speciation can occur which some reactionary creationists say is impossible.


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## Dagmire

I disagree with you. It took a high degree of intelligent effort, rethought and refigured, in order to make it happen. It in no way proves that speciation can occur with no intelligent interference.

And they're still fruitflies!


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## reformedman

Over my head but....
This conversation sounds a bit like the donkey / mule thing.

*Mule:* A domesticated, hybrid animal that results from crossing a mare (female horse) and a jack (male donkey). It results in a sterile animal better for pack riding.


<-------


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## Dagmire

It is basically the same thing. If the genetics of a creature mutate too far from its original design, the creature becomes sterile. Every chimera that the human race has produced through cross-breeding has been sterile. Life cannot propogate outside of the created order.


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## Dan....

SRoper said:


> No it proves that intelligence _can_ alter creation, not the necessity of intelligence to alter creation.
> 
> If the claims hold up it also proves speciation can occur which some reactionary creationists say is impossible.



That is prexactly what I am saying! ...and if one species can split into one or more similar but different species, then one could hypothetically over time end up with several species that become more and more different until you say, "this looks nothing like a fruit fly."

So, are the claims substantiated? Are there any credible articles that claim deficiency in their experiment?

I'm having very little luck finding Creationists responses to this experiment on the web outside the standard line that "they're still fruit flies." 

Also, when you say "some reactionary creationists say is impossible" does that imply that there are at least some creationists that are okay with speciation?


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## Dan....

Dagmire said:


> It is basically the same thing. If the genetics of a creature mutate too far from its original design, the creature becomes sterile. Every chimera that the human race has produced through cross-breeding has been sterile. Life cannot propogate outside of the created order.



Not the same thing. The fruit flies did not become sterile. Only when attempting to cross the one strain of fruit fly with the other (which previously produced fertile fruit flies) did they have sterile offspring. Both strains when bread within their respective strain still produced fertile offspring.


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## Dan....

reformedman said:


> Over my head but....
> This conversation sounds a bit like the donkey / mule thing.
> 
> *Mule:* A domesticated, hybrid animal that results from crossing a mare (female horse) and a jack (male donkey). It results in a sterile animal better for pack riding.
> 
> 
> <-------




A donkey "_Equus asinus_" and a horse "_Equus caballus_" are of the same family "Equidae" but are not the same species. To be the same species requires fertile offspring.

Species -


> http://en.wikipedia.org/wiki/Species
> Most textbooks define a species as all the individual organisms of a natural population that generally interbreed at maturity in the wild and whose interbreeding produces fertile offspring. Various parts of this definition are there to exclude some unusual or artificial matings:
> 
> * Those which occur only in captivity (when the animal's normal mating partners may not be available) or as a result of deliberate human action.
> * Animals which may be physically and physiologically capable of mating but do not normally do so because only their normal mating partners perform the courtship rituals or some other behavior "correctly".
> * Animals whose offspring are normally sterile. For example, mules and hinnies have never (so far) produced further offspring when mated with a creature of the same type (a mule with a mule, or a hinny with a hinny).



The fruit flies of different strains had been able to breed with fertile offspring (hence same species by definition) but were not after several generations (hence different species by definition).


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## Dagmire

I believe it is a logical fallacy to say that because of this "new species" that became, it could potentially, given enough time and enough generations, become something that is entirely unlike a fruitfly.

A fruitfly is a fruitfly is a fruitfly! I don't care if it has a wing on its back or eyes on its ass, it is still a fruitfly. I do not see an altered species of fruitfly as proof that something other than fruitflies can be produced by fruitflies.


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## Kenneth_Murphy

You may find this brief article interesting.

http://www.ucl.ac.uk/taxome/jim/pap/malletjeb01.pdf

It basically talks about how the Darwin type view is being changed to handle all the knowledge coming from genetics / biochemisty etc which operate on a lower level.

Point (2) in the article is interesting as it basically says that there is much debate currently on how even to define a species. The definition of a species is very important to proving if you can "evolve" one into another.


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## Dagmire

Yes, I was reading something similar to that on the other website. It leads me to believe that scientists will use their bias toward evolution to define a species in the most "evolution-friendly" way they can think of.


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## cih1355

Dan.... said:


> That is prexactly what I am saying! ...and if one species can split into one or more similar but different species, then one could hypothetically over time end up with several species that become more and more different until you say, "this looks nothing like a fruit fly."




There are limits to biological change. Fruit flies cannot change to the extent that over time it will change into something that does not look like a fruit fly.

Even if one gave the fruit fly an infinite amount of time and generations to change, it will never change into something that does not look like a fruit fly because its DNA limits how much change can occur.


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## Dan....

cih1355 said:


> There are limits to biological change. Fruit flies cannot change to the extent that over time it will change into something that does not look like a fruit fly.
> 
> Even if one gave the fruit fly an infinite amount of time and generations to change, it will never change into something that does not look like a fruit fly because its DNA limits how much change can occur.




Please expand on this:

How can we know that? Are there any articles that you can point me to?

Thanks.


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## Dan....

Kenneth_Murphy said:


> You may find this brief article interesting.
> 
> http://www.ucl.ac.uk/taxome/jim/pap/malletjeb01.pdf
> 
> It basically talks about how the Darwin type view is being changed to handle all the knowledge coming from genetics / biochemisty etc which operate on a lower level.
> 
> Point (2) in the article is interesting as it basically says that there is much debate currently on how even to define a species. The definition of a species is very important to proving if you can "evolve" one into another.




Much of this article is over my head. 

Can someone paraphrase the following in layman's terms -



> Instead, he finds total reproductive isolation
> meaningless given evidence for transfer of genes between
> closely related Drosophila species. Other loci within the
> same genomes become genealogically distinct, either
> because they contribute directly to selection against
> hybrids, or because they are trapped in parts of the
> genome contributing to such selection (Wang et al.,
> 1997; Wu, 2001).


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## August

Dan, did you see this:
Fruit flies speak up


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## SRoper

Dagmire said:


> I disagree with you. ... It in no way proves that speciation can occur with no intelligent interference.



I agree with this statement, just not the original one of yours I quoted.



Dagmire said:


> I believe it is a logical fallacy to say that because of this "new species" that became, it could potentially, given enough time and enough generations, become something that is entirely unlike a fruitfly.
> 
> A fruitfly is a fruitfly is a fruitfly! I don't care if it has a wing on its back or eyes on its ass, it is still a fruitfly. I do not see an altered species of fruitfly as proof that something other than fruitflies can be produced by fruitflies.



You are right that it is a logical fallacy to say that. However, many creationists assert that speciation doesn't happen at all. If this finding holds up it proves them wrong on this point.



cih1355 said:


> There are limits to biological change. Fruit flies cannot change to the extent that over time it will change into something that does not look like a fruit fly.
> 
> Even if one gave the fruit fly an infinite amount of time and generations to change, it will never change into something that does not look like a fruit fly because its DNA limits how much change can occur.



I believe this is also fallacious reasoning. Just because it has not been directly observed doesn't mean it is impossible.


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## cih1355

Dan.... said:


> Please expand on this:
> 
> How can we know that? Are there any articles that you can point me to?
> 
> Thanks.




Here are two articles that discuss the limitations of biological change:

http://www.probe.org/faith-and-science/origins/the-natural-limits-to-biological-change.html

http://www.answersingenesis.org/home/area/re1/chapter2.asp


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