A biosphere is an area of the earth that can support life and is also referred to as the ecosphere. It is the sum total of all ecosystems such as the atmosphere (air), hydrosphere (water), and lithosphere (rock) which exist together in a highly integrated and interacting manner. The earth's biosphere is estimated to have evolved at least 3.5 billion years ago by a process known as biopoiesis (the formation of life naturally from non-living components such as simple organic molecules) or biogenesis (life created from living matter).
In 1875, geologist Eduard Suess coined the term "biosphere," which he defined as "the area on the Earth's surface where life exists." The biosphere is a nearly closed system with limited inputs and outputs in terms of substance.
Key Features of Biosphere
Very Thin Layer That Supports Life: If Biosphere were to be imagined like a thin layer that wraps around the Earth's surface then it will be as thick as the apple's skin with the world to be the size of an apple. Life in the biosphere extends between 200 metres (660 feet) beneath the ocean's surface and 6,000 metres (20,000 feet) above sea level.
The distribution of living species across the biosphere is not uniform. The arctic areas are home to a small number of creatures, whereas tropical rain forests are home to a diverse range of plants and animals (50 per cent of Global Biodiversity).
No life in Extemeties: The North and South poles, the tallest mountains, and the deepest oceans do not support life due to extremities and hence the biosphere is absent. Only fungi and bacteria spores have been found at altitudes over 8,000 metres on rare occasions, however, they are not metabolically active and hence represent only latent life.
Energy Recycling: The sun provides the necessary energy for life to exist within the biosphere. Air, water, and soil provide the essential nutrients for living organisms. For life to persist, the same chemicals must be recycled repeatedly. Biospheres, in a broad sense, are any closed, self-regulating systems that contain ecosystems.
A number of artificial biospheres have are being operated around the world to understand how these closed systems work and several attempts have also been made to develop extraterrestrial biospheres such as Biosphere 2 which is the largest artificial closed ecological system.