... that have lived on the Earth since life first appeared here three billion years ago, only about one in a thousand are still living today. All the others have became extinct usually within ten million years after they first appeared. This in turn has contributed greatly to the current level of biodiversity on the planet. Extinction is the loss of populations of interbreeding ... the human population is the primary reason for the increase in the rate of extinction. Since 1600 about 1100 species have became extinct. The rapid disappearance of species was ranked as one of the planet's grave...

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• Approx Pages: 12
• Grade Level: High School