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Posted on 12/10/2009 9:27:01 AM PST by neverdem
New species might arise as a result of single rare events, rather than through the gradual accumulation of many small changes over time, according to a study of thousands of species and their evolutionary family trees.
This contradicts a widely accepted theory of how speciation occurs: that species are continually changing to keep pace with their environment, and that new species emerge as these changes accrue. Known as the 'Red Queen' hypothesis, it is named after the character in Lewis Carroll's book Through the Looking-Glass, and What Alice Found There who tells a surprised Alice: "Here, you see, it takes all the running you can do, to keep in the same place."
The Red Queen hypothesis rests on the idea that species must continuously evolve just to hang on to their ecological niche. That gradual evolution is driven by the constant genetic churn of sexual selection.
A consequence of this is that all of the species in a particular family, or genus, gradually evolve to form new species at the same rate.
But Mark Pagel and his team at the University of Reading, UK, challenge this idea. In a paper published today in Nature, they compared four models of speciation — one of which was the Red Queen hypothesis — to see which best explains the rate of speciation in more than 100 species groups from the animal and plant kingdoms, including bumblebees, turtles, foxes and roses.
They looked at the lengths of branches in thousands of species'...
--snip--
The team's findings might stir things up in the world of evolutionary biology. "It really goes against the grain because most of us have this Darwinian view of speciation," says Pagel. "What we're saying is that to think about natural selection as the cause of speciation is perhaps wrong."
(Excerpt) Read more at nature.com ...
Hat-tip to Road Gumby for tracking this little gem down :o)
All the best—GGG
You mean something like this???
AiG: Weekly News
Q: Can speciation occur quickly?
A: If the account of Noah’s Ark in the Bible is true, then two of every kind of land animal (and seven of some) came off Noah’s Ark in the Middle East. For instance, two members of the dog kind walked off the Ark. Then, as the number of dogs increased, eventually the population split up and different groups formed.
As the gene pool was split up, different combinations of genes—inherited from the original dogs—would end up in different groups. Thus, different species would form, such as dingoes, wolves, and so on.
Evolutionists have often insisted that such a process happens slowly, and therefore, the Bible can’t be right when it says that the land animals came off the Ark only about 4,300 years ago.
But in the journal Science, a report stated:
“These examples say that natural selection can cause a population to change very quickly and hint that speciation could [occur] very quickly …”
Once again, true operational science confirms the biblical history. The account of Noah’s Ark in the Bible fits with real observations, including natural selection and speciation.
http://www.answersingenesis.org/e-mail/archive/AnswersWeekly/2007/0721.asp
That is a position also taken by creationists like those at AiG.
They contend, as I understand it, that because life was created with perfect, functional DNA, (no junk) that as populations became isolated, certain traits were lost, allowing others to express. That would be a loss of information.
The ToE says that information is gained.
However, even if this new concept takes hold that it’s through reproductive isolation and information is indeed lost through that, there still arises the question of where the information came from in the first place.
Sounds like the hypothisis that all life had one beginning...
That doesn't seem unreasonable, PROVIDED that there is a lot of genetic material to begin with.
If genetic material is added by time and chance mutations, that would be a much slower process. That wouldn't allow for fast, large changes as there wouldn't be sufficient material available to sustain that kind of rate.
Rather, it sounds like the hypothesis that all life forms began at one beginning...
Rather, it sounds like the hypothesis that all life forms began at one beginning...
==That doesn’t seem unreasonable, PROVIDED that there is a lot of genetic material to begin with.’
Precisely! You make informational changes with information you don’t have. Excellent point Metmom!
The “fits and starts” model was first postulated to counter-act the lack of smooth progression of organisms that Darwin claimed should be in the fossil record. It is a model that requires the absence of data to be valid. Unless, of course, you can show “fits and starts” happening repeatably in the present.
I’m a little rusty in this (college bio major), but what makes this different than punctuated equilibria, ala Steven Jay Gould?
Or how God arose in the first place. Both sides can get stuck on that one...
But I did not know that creationists believed in the reproductive isolation stuff. Thanks...
It didn't used to be with me, but I'm coming around. I heard a great deal about genetic drift in my evolution classes....and yet we have the coelecanth. What happened there? Sure, maybe there was no overt environmental selection pressure, but oughtn't there be at least some random drift in such a small population--and over the time frames we are talking about it, wouldn't it have been enough to cause some serious anatomical changes?
I dunno. Too many groups in too much stasis over too great a time. Like you said, fits and starts. Not many smooth flows.
If by 'evolutionary biology' we simply mean biologists who study the nature of changes in the biological world, I have no problem with this remaining unchanged. Indeed, there are creationists biologists who might as well be called evolutionary biologists already. I know one creationist biologist whose job title is 'plant transformation specialist.'
I dunno. Too many groups in too much stasis over too great a time. Like you said, fits and starts. Not many smooth flows.
No matter how you slice it, there are issues with the ToE that just strain its credibility.
"fits and starts"
OK with me, a chem major.
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There was some moth in England that was mostly white, but which then became mostly black, when the industrial age coal dust pollution made "mostly black" better camo. Then when that was cleaned up, it went back to "mostly white/gray". This was not adaptation by individual moths, but multigenerational changes to the species. The same effect is seen when bacterial species develop immunity to antibiotics. Those that happen to have better resistance, or better camo for the moths, live and reproduce, while the others die off and/or are eaten.
Sometimes the species doesn't survive the transition. Dinosaurs for example. The problem is that the process generally takes several generations, sometimes more than merely several, and in those animals that have lifespans meansured in years, that can take a long time, too long to be considered "in the present".
The whole process is no mystery to animal breeders, who provide both the culling and the increased reproductive success for the "desired" variations. But those are generally relatively long lived species, and the best that people can do is change traits. Creating a whole new species would take much longer, and would require a large but isolated population.
Dad used to take our culls to "underprivileged" senior citizens, who ate them. Mom refused to cook pigeons. :) (When he had chickens, the culls did get eaten.)
I think it's a combination of both isolation and environmental change. With only isolation, it still might occur, but it would take a lot longer, since most variations would not produce much of an improved reproductive success, nor would they result in much "culling" by the environment. But when the enivronment changes drastically and there are isolated populatons and thus no mixing, at some point the differences between the two (or more) populations may become large enough that they can no longer interbreed, as each population takes a different path to adapting to the new environment.
An exception might be if the "environmental effect" kills off so many species that there are lots of open "slots" in the new ecology, in which case mulitiple species may result.
Of course who/what drives the environmental change?
Sure...and do not underestimate the founder effect.
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