Jon Krakauer

When I was 23, I climbed this mountain in Alaska called Devil's Thumb alone. It was incredibly dangerous, and I did it because I thought that if I did something that hard and pulled it off, my life was gonna be transformed. And of course, nothing happened. But I get the search for purpose.

The genus Drosophila is one of the great success stories. There's hundreds of species within the genus. They're on every continent except Antarctica, they're in tropical rain forests, they're in deserts, they've evolved many exotic mating behaviors, and they're capable of incredibly long-distance flights.