There are many reasons for the loss of biodiversity around our planet. These serious issues affect both plants and animals. Did you know that throughout history the earth has gone through several periods called mass extinctions. In the past, these have been occurred due to natural causes such as volcanoes and natural climate change. Today we've entered into another period of mass extinctions. This time however, it is caused by human activities! People have overfished, overhunted, destroyed habitats, and used harmful chemicals. Our planet's biodiversity is in danger! Follow the links to learn about the problems threatening our biodiversity.