Extinction is a part of nature. In fact, an estimated nine percent of species become extinct every million years or so, a rate that works out to between one and five species per year. Five times in Earth's history this rate has speeded up, causing extinction on a massive scale and eliminating at least half the animal species living. Now, 65 million years after the last of the dinosaurs disappeared in the most recent extinction episode, it's happening again.

But this time, species are becoming extinct at a rate many times faster. Some scientists say 10,000 times faster-than ever before. Roughly 10,000 to 25,000 species are disappearing each year, dozens per day. And unlike the five previous extinction spasms, this one isn't being caused by environmental change, but by the actions of our own species, Homo sapiens.

ACT NOW: Stop the Clock on Species Extinction.

Natural evolution will not be able to replace the species and rebuild the ecosystems being lost until humans alter the following types of biodiversity-harming behavior:

• Exploiting natural resources, such as the world's oceans, faster than they can be renewed
• Draining wetlands and clearing forests and grasslands for agriculture and towns and cities
• Ruining habitat by fragmenting it with roads and development
• Over-harvesting trees to make building supplies and paper products and for use as fuel
• Introducing harmful species into foreign ecosystems
• Releasing toxic pollutants
• Poaching, unsustainably hunting or illegally trading wildlife