Slashdot Mirror
Deep-Sea Microorganism Hasn't Evolved For Over 2 Billion Years
sfcrazy writes: Evolution is a natural process — everything evolves over a period of time, depending on the environment. But now scientists have discovered an organism which hasn't evolved for over more than 2 billion years. That's almost the half of the life of the Earth. "The scientists examined sulfur bacteria (abstract), microorganisms that are too small to see with the unaided eye, that are 1.8 billion years old and were preserved in rocks from Western Australia’s coastal waters. Using cutting-edge technology, they found that the bacteria look the same as bacteria of the same region from 2.3 billion years ago — and that both sets of ancient bacteria are indistinguishable from modern sulfur bacteria found in mud off of the coast of Chile." Scientists say the extreme stability of the environment around the organisms made further adaptations unnecessary.
Just because a fossil looks similar does not mean it hasn't evolved. Most evolution happens on the molecular scale, if you looked at the genomes I guarantee they would be different.
Morphological changes may have been minimal, but I suspect genomic changes have still occurred. Neutral drift alone would assure that these bacteria were not identical at the molecular level to their two billion year old ancestors.
The world's burning. Moped Jesus spotted on I50. Details at 11.
Most, but not all.
e.g. http://en.wikipedia.org/wiki/T...
In a simple and stable environment, the critters could have adapted a locally optimal form and strategy (given the evolutionary path they had already taken), to the point where all variations reachable from the current form function worse and are selected out. "reachable" is key here. You (your lineage) are very unlikely to evolve into spherical iron rock crystal creatures of roughly the same mass. The relative Kolmogorov complexity to get your form to that form, as well as the energetic infeasibility, mitigate against that direction, no matter how random evolutionary variation is. There are always constraints, not only on survival probability, but also on variation direction possibility.
This has zero to do with religion. It's about combinatorics, complex system constraints, and non-equilibrium thermodynamics.
Where are we going and why are we in a handbasket?
sometimes there is no force nor need for evolution.
.. and from TFS:
...made further adaptations unnecessary.
It really bugs me when I see the theory of evolution referred to this way. There is no "need" or "desire" or "necessary" involved. Similarly, "survival of the fittest" has nothing to do with who is in the (subjectively) best shape or who is the smartest (though there may be correlations). Fish did not decide that they'd like to walk on land or breath air (if they did, it had nothing to do with that happening).
If these things haven't evolved in 2 billion years, it simply means that any mutations that may have occurred resulted in lines that did not reproduce as effectively. That's still a very impressive feat, but it's not because it didn't "need" to, it's because when it did change it didn't do as well. In this case, it's very likely that this is at least partially due to the simplistic nature of this bacteria (fewer dip switches in its DNA, so to speak) and, of course, as the article points out, the very consistent environment (allowing for an optimized implementation to consistently out perform any random brethren).