At current rates we will loose 30% to 50% of all plant and animal species by 2050. Unlike previous mass extinctions this one is not being caused by volcanic eruptions, Earth's orbital fluctuations, or meteor strikes. This mass extinction is being created by HUMAN activity. Habitat loss through human development and deforestation, the introduction of exotic species that crowd out native species, and global warming (temperature rise, changes in rainfall, ocean acidification) -- these are the primary drivers for the sixth mass extinction on our planet.
Amphibians (frogs, toads, & salamanders) have been the hardest hit by habitat loss and changes in rainfall. Bird populations are declining world-wide. Twenty-one percent of all fish populations are at risk of extinction. Invertebrates (including reef-building corals) are doing poorly due to temperature increases. Increased carbon dioxide absorbed in ocean waters is causing mollusc shells to dissolve. 50% of the world's primates are threatened. 68% of plants are endangered. In drought stricken areas of the US, trees are quickly dying out due to water shortages. Read more about this topic at the Center for Biological Diversity.