That's a hunk of ecosystem small enough to fit in your lap. To answer the question, photographer David Liittschwager took a green metal frame, a 12-inch cube, to disparate environments -- land and water, tropical and temperate.
At each locale he set down the cube and started watching, counting, and photographing with the help of his assistant and many biologists. The goal: to represent the creatures that lived in or moved through that space.
The team then sorted through their habitat cubes, coaxing out every inhabitant, down to a size of about a millimeter. Accomplishing that took an average of three weeks at each site. In all, more than a thousand individual organisms were photographed, their diversity represented in this gallery.
"It was like finding little gems," Liittschwager says.