This module deals with biodiversity that is a study on the variety of different types of life found on the Earth and the variations within species. It is a measure of the variety of organisms present in different ecosystems. This can refer to genetic variation, ecosystem variation or species variation within an area, biome, or planet. Biodiversity is not distributed evenly on Earth. It is richest in the tropics. The richness of biodiversity depends on the climatic conditions and area of the region. It is an essential component of nature and it ensures the survival of human species by providing food, fuel, shelter, medicines and other resources to mankind. These modules cover the definition, measuring, importance, types of biodiversity and threats to biodiversity. In addition, students can study causes and consequences of biodiversity loss; wildlife, fisheries and endangered species; and conservation and sustainable use.