Posted on 11/20/2005 9:27:40 AM PST by restornu
Scientists at the University of Arizona may have witnessed the birth of a new species. Biologists Laura Reed and Prof Therese Markow made the discovery by observing breeding patterns of fruit flies that live on rotting cacti in deserts.
The work could help scientists identify the genetic changes that lead one species to evolve into two species.
The research is published in the Proceedings of the National Academy of Sciences.
One becomes two
Whether the two closely related fruit fly populations the scientists studied - Drosophila mojavensis and Drosophila arizonae - represent one species or two is still debated by biologists.
However, the University of Arizona researchers believe the insects are in the early stages of diverging into separate species.
The emergence of a new species - speciation - occurs when distinct populations of a species stop reproducing with one another.
When the two groups can no longer interbreed, they cease exchanging genes and eventually go their own evolutionary ways becoming separate species. Though speciation is a crucial element of understanding how evolution works, biologists have not been able to discover the factors that initiate the process.
In fruit flies there are several examples of mutant genes that prevent different species from breeding but scientists do not know if they are the cause or just a consequence of speciation.
Sterile males
In the wild, Drosophila mojavensis and Drosophila arizonae rarely, if ever, interbreed - even though their geographical ranges overlap.
In the lab, researchers can coax successful breeding but there are complications.
Drosophila mojavensi s mothers typically produce healthy offspring after mating with Drosophila arizonae males, but when Drosophila arizonae females mate with Drosphila mojavensis males, the resulting males are sterile.
Laura Reed maintains that such limited capacity for interbreeding indicates that the two groups are on the verge of becoming completely separate species.
Another finding that adds support to that idea is that in a strain of Drosophila mojavensis from southern California's Catalina Island, mothers always produce sterile males when mated with Drosophila arizonae males.
Because the hybrid male's sterility depends on the mother's genes, the researchers say the genetic change must be recent.
Reed has also discovered that only about half the females in the Catalina Island population had the gene (or genes) that confer sterility in the hybrid male offspring.
However, when she looked at the Drosophila mojavensi s females from other geographic regions, she found that a small fraction of those populations also exhibited the hybrid male sterility.
The newly begun Drosophila mojavensis genome sequencing project, which will provide a complete roadmap of every gene in the species, will help scientists pin down which genes are involved in speciation.
Why do you think they are called "fruit" flies?
Bull crap. Or more accurately, dinosaur crap. Ever consider that if something that contradicts with the current view of the ToE is backed by evidence, then it gets considered, and the stuff you think is getting unfairly silenced simply doesn't have any backing it up?
Your links to crap do nothing to prove or disprove my opinion. As occurs with any group of people in any field whose belief systems approach rabidness and whose agenda becomes the agenda: dissenting credible alternatives, ideas, studies, theories, and statements which deviate from the group mentality are unwelcome, ignored, and silenced, and more often than not, the messengers of same are subjected to contempt and pillory, perfect examples of same exist on these threads.
I posted links showing an example of a discovery that 'deviated from the group mentality'. This discovery has been welcomed, considered, publicized, and its discoverers have been credited and commended on their work.
I do understand, however, that your opinion is under no obligation to be right, so naturally you are likewise under no obligation to modify it in the face of refuting evidence. Speaking for myself, that does mean that I have no incentive to accept what I perceive to be an opinion detached from reality as credible. I doubt that really bothers you though.
Still, I am a bit curious to know if you have any examples of contemporary dissent backed with empirical evidence that does fit your perception of not being treated fairly. If so, I'd like to hear them.
"Sounds more like a new classification or breed, as it were, rather than a new species. They're still fruit flies."
Dimensio called this waaaaaaay back in post #12:
http://www.freerepublic.com/focus/f-chat/1525629/posts?page=12#12
Which, and how many, of the countless posts of voluminous works/scientists opinions, already cited by various FReepers with whom you disagree, have you found credible?
I am a bit curious to know if you have any examples of contemporary dissent backed with empirical evidence that does fit your perception of not being treated fairly.
Which, and how many, of the countless posts of voluminous works/scientists opinions, already cited by various FReepers with whom you disagree, have you found credible?
No creationist on this thread has offered "contemporary dissent backed with empirical evidence".
Not even close.
I can't recall any off the top of my head. That was kind of the point in asking for you to provide some examples.
I was hoping she'd be part of an attempt at a speciation event. Many attempts. The more the better.
I can't recall any off the top of my head. That was kind of the point in asking for you to provide some examples.
And your posts point out the very reason I asked; there is no point in attempting a discussion (I use that term in jest, as that is not even close to the display almost always seen on these threads in the name of "debate") with people who dismiss everything posted out of hand.
Your opinions are that the HUNDREDS of names/links to various scientists' dissenting opinions and studies, posted on FR on what must be thousands of posts and on a multitude of threads, which put forth dissenting theories/opinions/arguments/conclusions than the ones your and those in your "ping list/group" (i.e., FR evolutionarians) hold, are NOT CREDIBLE.
It's truly amazing....I've never seen such a consensus of opinion in the real world, science or otherwise.
I require that empirical evidence be present in order to qualify an assertion as credible. Please correct me by citing one of these hundreds of names/links that meet this criteria.
It seems you are relying on past dismissals of unsupported arguments to avoid presenting one that should be considered. I charge that you are using this dodge because you have no basis for your claim.
You, of course, can charge whatever you wish.
My charge: I find it more than preposterously amusing that the cumulative posts numbering in the thousands, which are contrary to, or dissent from, your agenda/belief system/ideas/opinions, have been and continue to be dismissed as not credible.
You continue to find it impossible to find any that were, or are. I remember learning that one task of a scientist is attempting to disprove and question their theories, not continually attempt to prove them.
Or are you really saying that faulty opinions should be accepted by fiat if there are a lot of them?
Oh, and to bring this back to the origin of our discussion, regarding your claim: 'No I doubt. I don't believe the crap I read in Science Journals, they won't print what scientists report who don't go along with their one way evolution ideas.
Number of evidence-backed cases I have cited to dispute this = 1
Number of evidence-backed cases you have cited to support this = 0
You dismissed out of hand an argument supported by evidence against your wild claim, yet accuse me of unfairly dismissing arguments that are not backed with evidence. You are what you accuse me of being.
It wasn't a wild claim; Science Journals do refuse to print science/studies which do not conform to their agenda. And what you posted earlier on grass has nothing to do with changing any fundamental agenda with evolution/theory, it alters only dates as to when they BELIEVE grass grew. Obviously, what they BELIEVED before was incorrect.
My opinion remains unaltered as to the preposterous likelihood that out of thousands of posts in FR, none (I didn't say all) have been credible by evolutionarians.
It's obvious to all you're a real man and your abilities include mind-reading....you're also skilled at divining intent better than the writer's written intent. And, last but not least, you enjoy arguing for argument's sake so much that you even go so far as to insinuate a writer is lying when they point out that their intent is what was written, not what you divined.
Is a sarcasm tag needed here so that you will not later state that wasn't my intent?
So why won't you present any evidence to support your assertions? Why should we believe you if you're going to balk at any request that you support your claims?
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