To live in the modern world is to swim in a sea of human-made chemicals, many of them toxic. And the results of that swim aren’t pretty. Air pollution can cause respiratory and cardiovascular problems. Chemicals leached from old batteries can cause renal disease. Mercury from coal-fired power plants and carbon monoxide from vehicle exhausts can cause reproductive problems. And this is a much abbreviated list of today's environmental hazards.
However, some animals adapt to environmental pollutants. Take, for example, a population of Atlantic killifish (Fundulus heteroclitus). These finger-sized minnows, sometimes called mudfish, live in some of the most polluted waters in the country. But these animals managed to survive, even thrive, thanks to some beneficial mutations that allowed them to adapt surprisingly fast to an environment that killed off many other species.
