Species Extinction
Species extinction occurs when the last member of a species dies, even though the ability to reproduce may have been lost before that point. Extinction occurs for a variety of reasons, both natural and man-made. In the last century human caused species extinction has been of major focus.
Some species have gone extinct due to overhunting, while others have suffered from habitat loss due to encroaching humans. In other cases human have introduced invasive species into a habitat with no defenses against these invaders. A good example is the introduction of rats and pigs to the Hawaiian Islands, which subsequently caused the extinction of dozens of species of native birds.
