Biodiversity refers to the variety of life on Earth, including the genetic diversity within species, diversity of species, and diversity of ecosystems. There are over 2 million identified species but many more remain unknown. Biodiversity is important because all living things interact in complex ways and biodiversity provides intrinsic value as well as utilitarian value like goods, services, information, oxygen, food, clean water, and medicine to humans. However, biodiversity is declining at an alarming rate due to threats like habitat destruction, pollution, invasive species, climate change, and exploitation, so conservation efforts are needed.