Definitions of Biosphere
“The Earth’s biosphere is a basically materially closed (some input from the solar system and from Earth’s interior and some output via subduction and escaping gasses), and energetically open to sources, sunlight, sun and moon gravity, and from Earth’s interior and to sinks (heat radiation and light reflection to space). The Earth’s biosphere is now informationally open as well to space programs launching information gatherers and receivers outside the biosphere. The Earth’s biosphere is a self-organizing, adaptive, complex system that increases its free energy in an amount substantially less (about 1%) than the difference in the free energy in molecular and informational organization.
The Earth’s biosphere has existed at least 3.8 billion years, survived five major species extinction events, and one atmospheric transformation, contains about a trillion tons of life distributed perhaps amongst 30,000,000 or more species and whose dynamics are based on mutation and natural selection evolving adaptive behaviors and a guild of biomolecules whose chemistry is able to increase its free energy with the evolution of complex ecosystems such as rainforests and coral reefs. The Earth’s biosphere has created and maintains its own improbable atmospheric composition, and produces an ever-growing “necrosphere” or geological strata of biogenic material such as soils, limestones, beaches, coal, oil formations and other deposits. Among its major attributes, it is the matrix of humanity and all its works, which include projects to take offspring biospheres throughout space.”
“The global ecological system, the biosphere, can then be defined as that part of the terrestrial surface which is ordered by the flow of energy, mediated by photosynthetic processes.”
Harold J. Morowitz
Energy Flow in Biology
Ox Bow Press
“It is the activity of living organisms that creates this extraordinary diversity of the “nature” around us, the extraordinary diversity of the biosphere. Perhaps, until recently we could not appreciate this diversity: we simply had nothing to compare our biosphere with. Only now, after we have seen on the screens of our television sets and on the pages of illustrated editions the landscapes of other planets, deprived of life, only now can we fully appreciate the “internal diversity” of the biosphere. This provides a definite guarantee for the preservation of life on our planet.”
Traces of Bygone Biospheres ( 1987)
Mir Publishers, Moscow.
“The tiny Archean sacs of DNA and RNA carried out their activities prodigiously. With sleep unknown to them they grew, consumed energy and organic chemicals, and divided incessantly. Their colonies and fibers interconnected and covered the sterile globe in a spotty film. The dimensions of this film have expanded into a patina of life, of biosphere, the place where life exists. Today the biosphere surrounds the earth from a little deeper than five miles into the ocean to over six miles up, near the mountain tops at the top of the lower atmosphere, called the troposphere. ”
Lynn Margulis & Dorion Sagan
“Although there may be problems in agreeing on a close definition of ‘biosphere’, that is not important. What is important is that there is widespread acceptance of the set of ideas conveyed by the term. The idea of living organisms as functional entities, processing energy and matter, reproducing, interacting with each other and with the physical environment; and the idea that the entire biota, together with its physical environment, can be regarded as a single system.”
The Biosphere (1991)