Natural selection may not produce the best organisms
July 18th, 2008"Survival of the fittest" is the catch phrase of evolution by natural selection. While natural selection favors the most fit organisms around, evolutionary biologists have long wondered whether this leads to the best possible organisms in the long run.
A team of researchers at The University of Texas at Austin, led by Drs. Matthew Cowperthwaite and Lauren Ancel Meyers, has developed a new theory, which suggests that life may not always be optimal. The results of this study appear July 18th in the open-access journal PLoS Computational Biology.
Genetic mutations create the raw material that natural selection acts upon. The short-term fate of a mutation is often quite clear. Mutations that make organisms more fit tend to persist through generations, while harmful mutations tend to die off with the organisms that possess them. The long-term consequences of mutations, however, are not well understood by evolutionary biologists. The researchers have shown that what may be good in the short run, may hinder evolution in the long run.
The team developed computer models of RNA molecules evolving by mutation and natural selection. RNA molecules, which are very similar to DNA, play key roles in essential life processes and serve as the genetic material for some of our deadliest viruses, including influenza and HIV.
Their computer models show that the evolution of optimal organisms often requires a long sequence of interacting mutations, each arising by chance and surviving natural selection. As Cowperthwaite explains, "Some traits are easy to evolve – formed by many different combinations of mutations. Others are hard to evolve – made from an unlikely genetic recipe. Evolution gives us the easy ones, even when they are not the best."
The group's analysis of RNA molecules from a wide variety of species suggests that life is indeed dominated by the "easy" traits, perhaps at the expense of the best ones.
Citation: Cowperthwaite MC, Economo EP, Harcombe WR, Miller EL, Ancel Meyers L (2008) The Ascent of the Abundant: How Mutational Networks Constrain Evolution. PLoS Comput Biol 4(7): e1000110. doi:10.1371/journal.pcbi.1000110
Source: Public Library of Science
Jun 04, 2009 |
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Kinda like how one could make the case that gas powered cars are more fit due to lower tech demands than hydrogen ones...
Unless the "more fit" but harder to evolve creature did get around to evolving, mr. average joe fitness would still have his niche to live in. Nobody said evolution produces the best organisms, but the best in the area at whatever it is they do tend to reproduce the most by definition of what life does.
Technicly true.
If you are in the ocean, "Best" will be completely different than on land.
If you are in the arctic, "best" will be compltely different than in the desert at the equator.
Additionally, if you've just had a meteor impact, "best" is completely different than a normal year.
"Survival of the fittest" is actually a complete misnomer, since a superior species on one continent or island can be irradicated by a disaster due to proximity, while an inferior species with a similar niche might survive on another continent or island.
Evolution is a theory of luck and mutation, and has nothing whatsoever to do with which species is the "best", nor does it even really attempt to define what "best" is.
Is a species of tree that survives 100,000,000 years *overall* better than one that survives 99,000,000? We should just write off that "lesser" tree as a failure? The human race will be lucky to survive that long!
DoctorKnowledge:
A polite disagreement: I think best can be effectively defined here because it is attached to the concept of "evolution by natural selection". Hence the organism with the greatest ability to pass on it's genes. Though granted, "best" in the abstract is quite ephemeral.
edit: sorry d666, didn't see your post. You beat me to the punch.
The chance that evolution will produce either one is infinitesimal due to its random nature and the immense volume of parameter landscape.
"The human race will be lucky to survive that long!"
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True, the human race probably won't. But the human line of descendants might.
And they will no longer be human.
http://en.wikiped...isficing
Evolution satisfices rather than optimizes.
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Ultimately, it's whatever we want it to be - within the laws of physics, of course.