Fish dwelling the in PCB-laden Hudson River have evolved to adapt to their presence. The rslut: PCB-resistant fish.
Fish in polluted waters have evolved into toxin-resistant super mutants
These tiny brown fish live just downriver of a bunch of General Electric plants, which had been steadily dumping waste in the river for decades until the practice was halted in the early 1980s. But the damage was done, and the particularly dangerous chemicals, polychlorinated biphenyls (PCBs) and dioxins, can still be found in heavy concentrations throughout the Hudson. When the dumping stopped thirty years ago, 94% of the adult tomcod had a PCB-induced tumor on their liver.
After making that initial discovery, New York University researcher Isaac Wirgin spent decades studying how the tomcod changed to meet this devastating new ecological paradigm. The results were shocking:
I started working on these fish with the hypothesis that they would be very sensitive to the toxic effects of PCBs. But the more work we did in controlled lab studies, we found that they were highly resistant to the toxic effects of PCBs and dioxin."
Yes, in the last thirty years, the tomcod have mutated, and every fish that has ever been taken out of the river in the last few years has been found to possess a gene that greatly reduces the dangers of PCBs and dioxins. It's allowed the fish to survive in waters that would be lethal to their counterparts elsewhere, but the fish have suffered in other ways. They likely grow slower than other tomcod, and they may have reduced resistance to other dangers.
What's fascinating to me is that this adaptation took hold so quickly.
Not only that, but evolution has been witnessed in a laboratory setting, as well, when a strain of e.coli, which cycles through generations quite rapidly, suddenly displayed a similar adaptation:
[S]ometime around the 31,500th generation, something dramatic happened in just one of the populations - the bacteria suddenly acquired the ability to metabolise citrate, a second nutrient in their culture medium that E. coli normally cannot use.Have whatever faith you want; it's not monkeys turning into humans while Christine O'Donnell watches, but evolutionary leaps are taking place all around us.