The ocean current's cycle depends on the density of water in the North Atlantic caused by the higher salt content added by the Indian Ocean, so that the current sinks and flows back to the south with conveyer-belt precision. Somehow connected with this verifiable information is the inconsistent data on the melting of icecaps, the ozone layer, and the uncertain weather trends toward warming and cooling. Many question the seemingly minor effects of man-made pollution versus the incomparable effects of natural occurrences. This debate does not diminish our responsibility to quantify the effects of pollutants on the evolutionary process. Evolution is irreversible, and if we cannot identify pollutants that affect evolution and quantify their effects, there is no opportunity to even consider whether the outcome might be negative or positive and whether to prevent the changes.
Evolution requires genetic change and environmental factors, driven by selection.
In addition, it is likely that natural events such as hurricanes and earthquakes could also play an important role in the evolutionary process, simply by altering the distribution of species and allowing selection to proceed. It is unlikely that in my lifetime we will readily attain the knowledge to test the hypothesis that pollution exerts a global influence on evolution. I have more confidence that with the will to do so, and with the gain of greater scientific knowledge aided by the development of powerful parallel computational ability, eventually we can begin to quantify the effects of pollution on the evolutionary process, and maintain the diversity of life required by healthy ecosystems. Michael P. Dieter Science Editor References 1. Hickman CP, ed.