Science Wednesday: Lessons on Modern Toxicology – How Darwin Saw It Coming.

Each week we write about the science behind environmental protection. Previous Science Wednesdays.

About the author: Dr. David Reif is a Statistician in the National Center for Computational Toxicology with the EPA’s Office of Research and Development in Research Triangle Park, NC. He holds degrees in Biology, Statistics, and Human Genetics—giving him an abiding appreciation for the lasting impact of Darwin’s theories.

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From an evolutionary perspective, should we be surprised that our bodies sometimes react inappropriately to novel chemicals encountered in the environment? According to the principles of adaptation by natural selection laid out by Darwin, the answer is “not at all.”

Each of us alive today is the product of tens of thousands of years of environmental adaptation. This long evolutionary process allows modern humans to respond appropriately to a remarkable set of naturally-occurring substances.

In contrast, people have had comparatively zero time to figure out how to handle the myriad of man-made chemicals introduced since industrialization. Even at the earliest centers of the Industrial Revolution, we’ve had less than 10 generations to obtain evolutionary solutions to previously unseen combinations of substances. Given that Darwin posited “incomprehensively vast” time periods for natural selection to arrive at workable solutions, he would not be surprised that humans have yet to adapt. Neither should we.

Modern civilization has given us all sorts of incredible tools for fighting diseases, making more efficient use of natural resources, and dealing with identifiably toxic substances. However, along with this progress, we have burdened ourselves with an unquantified volume of synthetic substances to which we are all exposed (to various degrees) on a daily basis. This tension between the needs of modern society versus the volume of new chemicals introduced into the environment puts enormous pressure on our bodies to appropriately respond.

Does that mean we must wait patiently while hoping that natural selection weeds through humanity to settle on appropriate adaptations for continuously shifting environmental conditions? No! Thankfully, a key adaptation of modern society is compassion—meaning that we must explore potential toxic effects of all new chemicals through smart science and careful consideration of relevant ethical, legal, and social consequences. Darwin would be proud.