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.
One theory of life is that all 'life' forms are just various mutations of a virus. Earth has one kind of intelligent virus and other planets in the universe might have other virus forms which could be considered life as well.
Why wouldn't a virus be considered a life form?
nothing....but I'll be in California for a bit of time.....perhaps we'll even go out to the desert and soak up some rays. : )
Palm Springs area?
Not at all. My question is whether any IDers also fear Bird Flu. They can squirm out of the question by denying that viruses are living in the first place.
C'mon you guys, focus... What do you think of this evolutionary stuff? Seriously.
By the end of 1984, 62 genera and 2,822 described species of this family were known worldwide, and at least 4,000 species were predicted to exist (Wheeler 1986). This catalog records over 1,000 species in 65 genera and subgenera from the Australasian/Oceanian Regions.All of these forms are still in the one big family. When something evolves all the way out of that family, we get to wake up fzx12345.
Except the way cladistics works, we probably never get to wake up fzx12345. That's because when you can't describe Drosophilidae with just species, genera, and maybe the occasional recourse to sub-genera, you don't create a new family alongside the existing Drosophilidae. IOW, if something is known to have originated within Drosophilidae, we try to preserve that relationship forever.
Thus what you do is you bump Drosophilidae up a notch and now it's an order rather than a family. Nothing ever wanders "out" of it.
Of course, the order that used to contain Drosophilidae bumps up a notch, too. Maybe you just call it a super-order to contain the ripple effect, or maybe you call it a class. If you do the latter, now Insecta becomes a super-class or something. For sure, you don't create a new phylum unless there's a whole new body plan, so you have to get inventive somewhere along the way up the hierarchy.
There has been so much effort put into asserting that a living cell must have certain this and that to qualify as no-question life, that viruses have been marginalized. They do have the composition of parts of cells. It is the part that seems to drive mutation and evolution, but can it carry consciousness?
Palm Desert
I hear ya. Yes a virus is alive IMHO. But I am not a microbiologist.
What's the definition of consciousness? Free will?
sounds like a nice time to visit too.
I have my own ideas but, just like everyone else, since no one was around, it's all theories/speculation. Credible science includes the scientific method---the ability for anybody to reproduce the "test" and have the same effect. And that's not possible with much of these theories or speculations.
glad to be there for a couple of weeks, rather than endure the coldness/dreariness here for months on end.
*Shrill warning sirens*
:-)
Consciousness is the subject of many books and articles going back thousands of years. Has the definition been nailed down yet? Is there such a thing as free will? Is free will even possible? The jury is still out, even though ex cathedra readings have been emitted.
lol! oh well, too bad. : )
:-)
I hear ya. Just thought I'd try to get you guys involved in the evo thread. I do have to go.
By any chance, Did anyone write a paper for me this morning on the heuristics of an object-oriented expert support system for design collaboration: A rear spar structure aerospace application? ;(
I'll bet no one did. :( God! I love to screw around!
Show off.....
Sounds like it's up the shark's alley all right!
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