The part of the earth where life exists is the biosphere. The biosphere is the portion of the Earth that supports life, including all living organisms and their interactions with each other and with the non-living parts of the Earth, such as the atmosphere, hydrosphere, and lithosphere. It includes all living things, from tiny bacteria to giant whales, and extends from the depths of the oceans to high in the atmosphere. The biosphere is where all the biological processes that sustain life occur, and it is essential to the survival of all living organisms.