A fascinating NYT story looks at evolutionary biologists who work in NYC, studying the way that species mutate to adapt to urban life. From cod that became PCB resistant after GE's notorious 30-year poisoning of the Hudson to mice whose city-wide genetic divergence is as broad as the whole global population's, to ants that have adapted to life on traffic islands:

"New one! New one!" Dr. Dunn shouted over the traffic. He and Dr. Danoff-Burg were surveying the median for species of ants. Dr. Dunn had spotted Crematogaster lineolata, an ant species that he and Dr. Danoff-Burg had never found before in this particular urban habitat.

From his backpack, Dr. Dunn pulled out an aspirator, a rubber tube connected to a glass jar. Holding one end of the tube over the ant, he sucked it in. Instead of going into his mouth, the insect tumbled into the jar. (One hazard of urban evolutionary biology, said Dr. Dunn, is having your aspirator mistaken for a piece of drug paraphernalia.)

Dr. Danoff-Burg, Dr. Dunn and their colleagues chose to study the medians of Broadway to see how human activity alters biodiversity. In this artificial city, there is no environment more artificial than these medians, which sit on fill that was poured on top of subway tunnels. The scientists have found a blend of ant species, some that have been here since before the city existed, and others that have arrived more recently, hitching rides on ships, planes and trucks. The most common ant Dr. Danoff-Burg and Dr. Dunn encounter is the pavement ant (Tetramorium caespitum), which came from somewhere in Europe.