26 Feb 2009

Unnatural Selection

Learning from Mother Nature, a creature or institution will thrive and survive environmental changes if it can do the followings:

1. Allow mutations or new ideas to occur.
2. Let mutants compete with wild types.
3. Accept the result of natural selection.

Unfortunately, most institutions overlook the latter two points. When a new policy comes up, it replaces the old one totally although there is no evidence that it is superior. Many people hate conservatives who reject all new policies – ward arrangement, teaching timetable, office renovation, you name it. Nevertheless, conservatives are very important. They preserve the good old days as far as possible and put the burden of proof on those who propose changes. Since bad ideas outnumber good ones in general, brutal replacement of old policies with new ones tends to result in disaster in the long run.

In the January issue of Proceedings of the National Academy of Sciences, Chris Darimont and colleagues described vividly the result of unnatural selection. Under normal selection pressure, the mortality rate of a species is usually limited, and immature and younger organisms die first. In contrast, in ecosystems affected by human predators such as hunters and fishermen, the mortality rate is higher, and the largest and mature organisms are the main targets. As a result, evolution under this unnatural selection is much faster. Interestingly, the size of organisms decreases by an average of 20%, and the life cycle shortens by nearly 25%. The poor preys just have to reproduce earlier to avoid extinction.

Sadly, the result of this report reminds us of ourselves. Good clinical research takes years or even decades of careful observation. Under the current method of research assessment, academics who only do big and long-term projects will die first because of insufficient research output. Next time when you read a me-too study or non-definitive study reporting dubious surrogate end points, don’t laugh. Those people are just shortening their reproductive cycle because of unnatural selection!

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