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Friday, November 15, 2013

Is there Supreme Fitness in Evolution?



Richard Lenski of Michigan State University has grown Escherichia coli bacteria since 1988. Even after 58,000 generations, he found that no supreme bacteria were produced. He expected that someday the bacteria would create the ultimate fit entity that was much stronger than their evolutionary predecessors. What he found was that evolution slowed but continued to adjust and change. 

The findings are significant in that it is assumed that eventually all creatures max out in their development. This is not true. As the evolutionary process develops, it never really hits its maximum peak. New peaks are always in sight so the species continues to develop. 

There is an assumption that biological change is a result of environmental change. If an environment stays the same, a species will reach its biological peak and any further mutations will force it downward into a less competitive stance. Decline becomes a type of biological crash whereby further adaptations put the system out of equilibrium and encourage its decline.

The authors do not go this far in their analysis but what if each creature comes with a DNA blue print or destiny for development? The changes in the environment will place pressure on the species to adapt either fast or slow but does not end that development. Adaption is always lagging as an effect because of constant pressures from the environment.  If the DNA cannot handle this change, or the amount of pressure, the species dies as the dinosaurs did when their environmental collapsed. 

If this were true then it would be possible to assume that species can handle environment changes if these changes are slow enough as to not overwhelm the DNA structure of the entity. Bacteria changes fast because they are a small entity within a larger system and therefore are sensitive to small environmental adjustments. Dinosaurs change slowly as they are a larger entity within a system and do not feel the same sensitivity of pressures. 

The bacteria in the experiment at MSU were adapting based upon the mechanisms of their DNA in an effort to catch up to the environment. As they came closer to homeostasis, they continued to develop but at a slower rate due to the fewer environmental pressures. Yet that artificial environment does not define their full developmental process and they will continue to grow regardless.

At present the researcher has concluded that there is no supreme fitness for bacteria and that they will continue to develop even at a slower pace.



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