City species evolve at warp speed

We've all heard that bedbugs have, as a result of natural selection, been producing pesticide-resistant strains. What may be surprising is that all kinds of other species affected by human activity have responded with new variants, producing, among other things, genetically distinct populations of mice in New York city parks separated by urbanity. This island evolution has been acting with a speed and effectiveness which surprises biologists, who are increasingly studying the results. One of the most striking examples: tomcod in the Hudson River have evolved immunity to the deadly pollutants known as PCBs. None of this means it's OK now to go ahead and further trash the environment. It does mean the process of natural selection is even more effective than we thought, and the island effect has implications for all kinds of cut-off habitat situations. Mother Nature still has a surprise or two for us....