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Author | Topic: Reverse evolution? | |||||||||||||||||||||||||||||||||||||||
subbie Member (Idle past 1277 days) Posts: 3509 Joined: |
An article in the Science Recorder reports:
Researchers from the University of Michigan have found evidence of reverse evolution in house dust mites. This discovery contradicts the belief that once an organism has evolved certain traits, it will never again act like its ancestors. Does anyone know anything about this? Is the media just screwing the story up completely, or is this truly the revolutionary discovery that it's portrayed as? I have more questions and thoughts, but I'm hoping someone here can explain things.Ridicule is the only weapon which can be used against unintelligible propositions. -- Thomas Jefferson We see monsters where science shows us windmills. -- Phat It has always struck me as odd that fundies devote so much time and effort into trying to find a naturalistic explanation for their mythical flood, while looking for magical explanations for things that actually happened. -- Dr. Adequate Howling about evidence is a conversation stopper, and it never stops to think if the claim could possibly be true -- foreveryoung
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Jon Inactive Member |
Well, I'm suspicious of the claim that biologists hold beliefs that "once an organism has evolved certain traits, it will never again act like its ancestors."
That just sounds like nonsense.Love your enemies!
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NoNukes Inactive Member |
I think Jon is right. The article mentions Dollo's law which is a hypothesis that evolution is not reversible. That does not mean that one or more traits that results from evolution might not disappear in the future.
Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846) The apathy of the people is enough to make every statue leap from its pedestal and hasten the resurrection of the dead. William Lloyd Garrison. If there is no struggle, there is no progress. Those who profess to favor freedom, and deprecate agitation, are men who want crops without plowing up the ground, they want rain without thunder and lightning. Frederick Douglass
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subbie Member (Idle past 1277 days) Posts: 3509 Joined: |
That was one of the thoughts I had. I have no problem with the idea that it's so unlikely that past mutations will reverse themselves that we can discard that possibility. But that doesn't seem the same thing as saying that an organism can't go from non-parasitic to parasitic to non-parasitic again. I can easily imagine that the mutations that might change it from parasitic to non-parasitic would be completely different from the mutations that made it parasitic in the first place.
I hope this makes as much sense in writing as it does in my head.Ridicule is the only weapon which can be used against unintelligible propositions. -- Thomas Jefferson We see monsters where science shows us windmills. -- Phat It has always struck me as odd that fundies devote so much time and effort into trying to find a naturalistic explanation for their mythical flood, while looking for magical explanations for things that actually happened. -- Dr. Adequate Howling about evidence is a conversation stopper, and it never stops to think if the claim could possibly be true -- foreveryoung
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AZPaul3 Member Posts: 8536 From: Phoenix Joined: Member Rating: 5.0 |
I must not be reading this right because I do not see the big rub.
There was a population in a niche as a free-living critter that spawned a sub-population that evolved into a niche as a parasitic critter. There was a population in a niche as a parasitic critter that spawned a sub-population that evolved into a niche as a free-living critter. The authors of the original study seem to feel that this free-to-parasite-to-free link is a violation of Dollo’s Law while what I can find on Dollo’s Law indicates that it pertains to an exact reversibility. I guess it depends on how one interprets Dollo’s Law. I very much doubt that some in-general kind of niche with the same proteomic chemistry is involved in the two free ends of this link. Will have to wait for the smart guys to chime in, of course, but right now I do not see it.
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Percy Member Posts: 22480 From: New Hampshire Joined: Member Rating: 4.8
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AZPaul3 writes: Will have to wait for the smart guys to chime in, of course, but right now I do not see it. I won't claim to be a "smart guy", but I don't see it either. I just now found the article independently and was about to start a thread titled, "Dollo's Law Overturned! Scientists Baffled!" when I saw this thread. Whatever the details of the house mite evolving gradually away from a parasitic lifestyle, it did so by way of descent with modification and natural selection. However unlikely someone wants to post facto declare that evolutionary path, that's how it happened. It did not retrace its evolutionary history (as the article puts it but which is not exactly Dollo's Law), and it did not precisely recover a prior form, which is what Dollo's Law purports to rule out. We usually suspect a newsperson as the source of idiocy in such cases, but after reading the article and the Wikipedia article on Dollo's Law I'm prepared to declare that it is all three: the newsperson, the lead author, and Dollo himself. Delila James is to be credited for doing some research and uncovering Dollo's Law, but she misapplied it to lifestyles. She apparently thought that Dollo's law prohibits a parasitic species from regaining the ability to live independently. But she wouldn't have misapplied Dollo's Law if the lead author of the paper hadn't said this:
Parasites can quickly evolve highly sophisticated mechanisms for host exploitation and can lose their ability to function away from the host body, Klimov said. They often experience degradation or loss of many genes because their functions are no longer required in a rich environment where hosts provide both living space and nutrients. Many researchers in the field perceive such specialization as evolutionary irreversible. He meant "evolutionarily irreversible" of course, but a biologist should not state so unequivocally that an organism can't evolve back to an old lifestyle, even if the one being abandoned is parasitic. The environment will select whatever variation favors survival to reproduce without regard to lifestyle. The specific new abilities mentioned in the article, ability to digest skin and a tolerance for low humidity, do not seem particularly incredible. What would have been amazing would be if scientists had discovered that in the process of evolving into parasites that dust mites had lost specific structures and processes, and then while evolving away from parasitism that they had regained the exact same structures and processes. They found nothing like this of course, but it is this that Dollo professes to rule out, and then Dalila James misinterpreted the head author as claiming that something like that had happened. But lastly I blame Dollo himself for creating a flawed law. As Dawkins said in the Dollo article, it's really a statement of unlikelihood of evolutionary history precisely repeating itself. Each tiny evolutionary step is a roll of the dice, and it is self-evidently true of anything that the unlikelihood of a precise repetition increases as the number of steps increases. Because this is self-evidently true it doesn't need a "law" to say it. But worse than that, if you consider very small evolutionary steps then Dollo's law is even self-evidently wrong because the smaller the evolutionary steps the less unlikely it is that they will be retraced. For example, life often retraces its recent evolutionary history when certain alleles in a population over time become common, then uncommon, then common again. And again and again. Like melanin in moths. But aside from the mere statistical considerations and getting back to the dust mite, if the dust mite lost structures and biological processes necessary to an independent lifestyle earlier in its evolutionary history, then new structures and processes must have evolved, or old ones must have been turned back on, or some combination. Evolution definitely did not flow in reverse --Percy
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Dr Adequate Member (Idle past 306 days) Posts: 16113 Joined:
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I don't think Klimov is much to blame. He didn't say that it can't happen (he thinks it did) but that many researchers had thought it couldn't. Which may well be true. It can't often happen that an organism rebounds from a parasitic lifestyle, and if this is the first known case he has a perfect right to gloat a little.
As for Dollo, it depends what he meant. But he can hardly have meant to deny (for example) flightless birds or aquatic mammals, can he?
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kofh2u Member (Idle past 3842 days) Posts: 1162 From: phila., PA Joined: |
I think Jon is right. The article mentions Dollo's law which is a hypothesis that evolution is not reversible. That does not mean that one or more traits that results from evolution might not disappear in the future. Whales evolved into land animals millions of years ago.But at some point, they reverted back to the sea animals again.
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CoolBeans Member (Idle past 3636 days) Posts: 196 From: Honduras Joined: |
But it was not reverse evolution. They even have different body structure from other sea life creatures. As you know they are mammals.
Great explanation Percy. Edited by CoolBeans, : No reason given. Edited by CoolBeans, : No reason given. Edited by CoolBeans, : No reason given.
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NoNukes Inactive Member |
Whales evolved into land animals millions of years ago. But at some point, they reverted back to the sea animals again. Whales never evolved into land animals.Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846) The apathy of the people is enough to make every statue leap from its pedestal and hasten the resurrection of the dead. William Lloyd Garrison. If there is no struggle, there is no progress. Those who profess to favor freedom, and deprecate agitation, are men who want crops without plowing up the ground, they want rain without thunder and lightning. Frederick Douglass
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kofh2u Member (Idle past 3842 days) Posts: 1162 From: phila., PA Joined: |
Whale Evolution:
Whales never evolved into land animals.
Have I ever misinformed you guys here...???? Call it an unfinished story, but with a plot that's a grabber. It's the tale of an ancient land mammal making its way back to the sea, becoming the forerunner of today's whales. In doing so, it lost its legs, and all of its vital systems became adapted to a marine existence -- the reverse (evolution) of what happened millions of years previously, when the first animals crawled out of the sea onto land. Evolution: Library: Whale Evolution
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kofh2u Member (Idle past 3842 days) Posts: 1162 From: phila., PA Joined: |
But it was not reverse evolution. They even have different body structure from other sea life creatures. As you know they are mammals.
You guys will try and try to circle your wagons when you meet the truth that correctsyou, but only your comrades will agree that you have a point: Whale Evolution: ... an ancient land mammal making its way back to the sea, becoming the forerunner of today's whales. In doing so, it lost its legs, and all of its vital systems became adapted to a marine existence -- the reverse (EVOLUTION) of what happened millions of years previously, when the first animals crawled out of the sea onto land.
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CoolBeans Member (Idle past 3636 days) Posts: 196 From: Honduras Joined: |
And that animal lost its fins when it became a land animal. What is your point?
A marine animal that lost its marine characteristics to become a land animal. Edited by CoolBeans, : No reason given.
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Eli Member (Idle past 3513 days) Posts: 274 Joined:
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That isn't "reverse" evolution.
That is evolution.
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CoolBeans Member (Idle past 3636 days) Posts: 196 From: Honduras Joined:
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Thank you!
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