Can Evolution Repeat?
by Luke Nix
Most people do not really think to ask this question about Evolution. However, it has become quite the important question in determining the validity of the paradigm. In this post when I refer to "evolution" I am referring to macroevolution (see my post "Useful or Useless Evolutionary Terms"). If I am talking about microevolution, I will make the distinction.
As I discussed in the previously cited post, random mutation does happen, and natural selection does operate on those mutations. This observation has been extrapolated over time into the theory of Evolution. According to the paradigm, life began as a single-cell organism, and through the process noted, we arrive at the state of life today (complex, mega-multicellular organisms).
Most people familiar with biology are know about the Long Term Evolution Experiment (LTEE). This experiment is touted as demonstrating that mutation does take place and can be observed. This demonstration is then used to conclude that Evolution is no longer a theory, and a proven fact (see the other post for the issues with this extrapolation- independent of the LTEE). Unfortunately, the LTEE actually raises a huge problem for the Evolutionary paradigm: the issue of historical contingency.
Noted evolutionary biologist Stephen Jay Gould describes Evolution as being unrepeatable. He used the analogy of a cassette tape. He stated that if the history of life was a tape, and that tape were rewound and played back, the second play would be radically different from the first.
Even though we can’t rewind the tape of time and play it back, we do have multiple copies of the same tape. All we need is a highly controlled, stable environment, and we would be able to test Dr. Gould’s theory.
The LTEE has demonstrated that random mutations that result in a usable feature will only repeat if the feature is only one mutation away from being produced. The frequency of that repeat was extremely small in the experiment. This means that random mutation can only produce the same outcome twice if the final mutation is a single step away, and the chances of that final mutation being the right mutation are minuscule (1 in 10,000). This supports Dr. Gould’s theory.
So what’s the big deal? We find many instances of "evolution repeating itself" in nature. One of my favorite examples is echolocation. Similar to SONAR. A high-pitched sound is emitted, and the sound waved bounces off objects back to the device. The location of the objects may be determined by the sequence of the sound waves received back. Both bats and dolphins possess this ability. Since they are so far removed from each other (from an evolutionary perspective), it is safe to say that the final mutation that led to the complete and functional echolocation system was more than a single step away. Which means that repeated echolocation is far from the possibilities of random mutations filtered by natural selection…
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