Scientists think we're on the brink of the greatest global loss of biodiversity since the extinction of the dinosaurs and many other species more than 65 million years ago. And human activity is the cause. We're at risk of losing thousands of species in the future, in many cases because we simply don't recognize how our actions affect other living things.

Alligator photo: Steven Morello

• The Nature of Change

• Losing Ground

• A Growing Concern

• Human Need and Human Greed

• Six Serious Threats