Biodiversity is the variety and variability of life on Earth — and it is under serious threat. More than 1 million species are at risk of extinction, by some estimates. Most people know that biodiversity is important, but why is it important, exactly? What does biodiversity have to do with the health and well-being of our own species? A lot, it turns out. In case you were wondering, here are five reasons why biodiversity is critical for us. 1. Wildlife supports the healthy ecosystems that we rely on. Conservation researchers Paul R. and Anne Ehrlich posited in the 1980s that species are to ecosystems what rivets are to a plane’s wing. Losing one might not be a disaster, but each loss adds to the likelihood of a serious problem. Whether in a village in the Amazon or a metropolis like Beijing, humans depend on the services ecosystems provide, such as fresh water, pollination, soil fertility and stability, food and medicine.…