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article imageOp-Ed: Chernobyl vs. evolution- Lessons from a horror story

By Paul Wallis     Feb 6, 2011 in Environment
Chernobyl - If any good is ever to come out of the Chernobyl disaster, it will have to be in the form of lessons learned. A new study is providing some evidence that the Chernobyl exclusion zone is causing physiological changes in wildlife.
Chernobyl isn’t a very nice place. It’s a dead area, and pictures of Chernobyl actually look worse as you understand them. It’s about the last place on Earth you’d expect to find anything but a sort of creeping obituary to life, the epitome of a post-nuclear movie set, but the new study has proven otherwise.
A study of 48 species of birds by an international group of scientists has discovered that newborn birds have smaller brains. Mammals and insects in the area are said to be in progressive decline. “Smaller invertebrates” aka everything else, are also said to be diminishing.
The birds, however, are exhibiting a known trait- The ability to vary organ sizes. This ability, understandably, has been of great interest. The variation in brain size between generations, however, is a truly extraordinary piece of information.
The BBC article on the subject rather slavishly includes a single line on its own:
Not necessarily. Studies of insect brains have shown that even tiny brains can be fully functional. In highly evolved species like ants, in fact, streamlining and improved efficiency are the natural products of evolution. A big brain is no advantage if it simply means a high maintenance, energy guzzling organ being required to do the same job.
The birds also seem to be the only higher organisms not in decline. The smaller brain size obviously isn’t having a significant impact on their viability. “Reduced cognitive ability” would also have to mean reduced survival skills, and perhaps even sensory dysfunctions. Reshuffling the organic configuration to deal with the situation, on the other hand, seems to be the alternative, and that’s a particularly interesting possibility.
If the reduction in organ size relates to reduced nutrition from invertebrates, a common source of food for birds, it would make perfect evolutionary sense. Reducing the size of an organ which is a literal glutton for energy would be good survival technique. Many species of birds, like those on islands, adapt in similar ways.
Another possibility, not suggested in the findings, is that Chernobyl may have accelerated an adaptive mechanism. Major physiological changes don’t usually happen in a single generation to multiple species in the same way at the same time. The evolutionary solution may be simply to reshuffle the organisms into a more efficient model.
If so, evolution may have more cards to play than the standard models of evolution and natural selection suggest. A freakish accident like Chernobyl may have triggered an evolutionary response that would otherwise have never have occurred.
The ramifications are huge. The rate and type of evolutionary change have been some of the hottest topics in biology since Darwin. A capacity to make major physiological changes virtually overnight on the usual scale could explain a lot about the mechanisms of speciation (development of subspecies) and clarify multiple issues in the vast range of differences between species. Evolution may well happen at multiple speeds in different ways, rather than the “single general bandwidth” model.
Darwin, in fact, included birds in his studies for The Origin of Species. Physiology, naturally, played a major part in his theories. A “rapid response” mechanism for changed environments would clarify the high levels of diversity seen in many bird species, and perhaps even clear up the “beaks issue”, which while clear enough about reasons for adaption, couldn’t set time frames.
There’s a sort of grim justice to the development of Chernobyl, as its effects become better understood. Chernobyl is an island, in many ways. If it can become a useful laboratory, instead of an endless horror story, it may yet be one of the most valuable disasters in history.
More about Chernobyl, bird brain size, theory of evolution
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