In Barbara Kingsolver's "Unsheltered," the author reflects on a nostalgic era when biologists made exciting discoveries of new species, contrasting it with the current time marked by widespread extinction. The characters Mary and Thatcher represent a generation that experienced the thrill of scientific advancement and the wonders of biodiversity flourishing around them.

This reflection serves as a reminder of the pressing environmental challenges we face today. As the natural world continues to diminish, it becomes increasingly important to cherish and protect our remaining species, drawing lessons from the past about the significance of biological diversity.