Biodiversity or  biological diversity, refers to the variety and variability of life forms on Earth. It encompasses the diversity of species, their genetic variation within species, and the variety of ecosystems in which they live.  It also refers to the interrelatedness of genes, species, and ecosystems and their interactions with the environment. Animal species make up more than 70% of all known species, while plants (including algae, fungi, bryophytes, gymnosperms, and angiosperms) make up no more than 22% of the total. In terms of taxonomic diversity, insects make up more than 70% of all animal species, making them the most diverse group. India is home to around 7% of all known species. The Amazon rainforest is home to the world's greatest biodiversity.