How Built Environments Hyper-Activate Evolution

Menno Schilthuizen writes a story of the incredible intersection between built and natural, as seen in the quickening pace of evolution among species living in urban settings.

"For a long time, biologists thought evolution was a very, very slow process, too tardy to be observed in a human lifetime," explains Schilthuizen. "But recently, we have come to understand that evolution can happen very quickly, as long as natural selection — the relative benefit that a particular characteristic bestows on its bearer — is strong."

The city, in its many manifestations, serves as the perfect testing ground, according to Schilthuizen. Now evolutionary biologists are focusing their work in cities, not faraway jungles and other extreme natural environments.

On a final, significant theme, there could be unpredictable evolutionary consequences as cities expand around the world. According to Schilthuizen, "as cities continue to grow, they will exchange more goods, people and information over greater distances. So each change in the environment (a particular pollutant, a certain novelty in road construction, a new kind of food source) will spread quickly across the world, and urban wildlife everywhere will be faced with the same novel challenge. Those that evolve adaptations will also easily spread to other cities, leading to a truly globalized urban flora and fauna — continually evolving at breakneck speed to keep up with an increasingly human-dominated world."