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Biosphere

2007 Schools Wikipedia Selection. Related subjects: Climate and the Weather

   A false-color composite of global oceanic and terrestrial
   photoautotroph abundance, from September 1997 to August 2000. Provided
   by the SeaWiFS Project, NASA/Goddard Space Flight Center and ORBIMAGE.
   A false-colour composite of global oceanic and terrestrial
   photoautotroph abundance, from September 1997 to August 2000. Provided
   by the SeaWiFS Project, NASA/ Goddard Space Flight Centre and ORBIMAGE.

   The biosphere is the outermost part of the planet's shell — including
   air, land, surface rocks, and water — within which life occurs, and
   which biotic processes in turn alter or transform. From the broadest
   biophysiological point of view, the biosphere is the global ecological
   system integrating all living beings and their relationships, including
   their interaction with the elements of the lithosphere (rocks),
   hydrosphere (water), and atmosphere (air). This biosphere is postulated
   to have evolved, beginning through a process of biogenesis or
   biopoesis, at least some 3.5 billion years ago.

   Biomass accounts for about 3.7 kg carbon per square metre of the
   earth's surface averaged over land and sea, making a total of about
   1900 gigatonnes of carbon.

Origin and use of the term

   The term "biosphere" was coined by geologist Eduard Suess in 1875,
   which he defined as:

     The place on earth's surface where life dwells.

   While this concept has a geological origin, it is an indication of the
   impact of both Darwin and Maury on the earth sciences. The biosphere's
   ecological context comes from the 1920s (see Vladimir I. Vernadsky),
   preceding the 1935 introduction of the term " ecosystem" by Sir Arthur
   Tansley (see ecology history). Vernadsky defined ecology as the science
   of the biosphere. It is an interdisciplinary concept for integrating
   astronomy, geophysics, meteorology, biogeography, evolution, geology,
   geochemistry, hydrology and, generally speaking, all life and earth
   sciences.

Narrow definition

   A familiar scene on Earth which simultaneously shows the lithosphere,
   hydrosphere and atmosphere.
   A familiar scene on Earth which simultaneously shows the lithosphere,
   hydrosphere and atmosphere.

   Some life scientists and earth scientists use biosphere in a more
   limited sense. For example, geochemists define the biosphere as being
   the total sum of living organisms (the " biomass" or " biota" as
   referred to by biologists and ecologists). In this sense, the biosphere
   is but one of four separate components of the geochemical model, the
   other three being lithosphere, hydrosphere, and atmosphere. The narrow
   meaning used by geochemists is one of the consequences of
   specialization in modern science. Some might prefer the word ecosphere,
   coined in the 1960s, as all encompassing of both biological and
   physical components of the planet.

   The Second International Conference on Closed Life Systems defined
   biospherics as the science and technology of analogs and models of
   Earth's biosphere; i.e., artificial Earth-like biospheres. Others may
   include the creation of artificial non-Earth biospheres — for example,
   human-centered biospheres or a native Martian biosphere — in the field
   of biospherics.

Gaia's biosphere

   The concept that the biosphere is itself a living organism, either
   actually or metaphorically, is known as the Gaia hypothesis.

Extent of the earth's biosphere

   Some theorists have postulated that the Earth is poorly suited to life,
   although nearly every part of the planet, from the polar ice caps to
   the Equator, supports life of some kind. Indeed, recent advances in
   microbiology have demonstrated that microbes live deep beneath the
   Earth's terrestrial surface, and that the total mass of microbial life
   in so-called "uninhabitable zones" may, in biomass, exceed all animal
   and plant life on the surface. The actual thickness of the biosphere on
   earth is hard to measure. Birds typically fly at altitudes of 650 to
   2000 meters, and fish that live deep underwater can be found down to
   -8,372 meters in the Puerto Rico Trench.

   There are more extreme examples for life on the planet: Ruppell's
   Vulture has been found at altitudes of 11,300 meters; Bar-headed Geese
   migrate at altitudes of at least 8,300 meters (over Mount Everest);
   Yaks live at elevations between 3,200 to 5,400 meters above sea level;
   mountain goats live up to 3,050 meters. Herbivorous animals at these
   elevations depend on lichens, grasses, and herbs but the biggest tree
   is the Tine palm or mountain coconut found 3,400 meters above sea
   level.

   Microscopic organisms (e.g., bacteria) live at such extremes that,
   taking them into consideration puts the thickness of the biosphere much
   greater, but at minimum it extends from 5,400 meters above sea level to
   at least 9,000 meters below sea level.

Biosphere 1, Biosphere 2, Biosphere 3

   When the word Biosphere is followed by a number, it is usually
   referring to a specific system. Thus:
    1. Biosphere 1 - The planet Earth
    2. Biosphere 2 - A laboratory in Arizona which contains 3.15 acres
       (13,000 m²) of closed ecosystem
    3. Biosphere 3 (aka BIOS-3) - Experiment conducted by Russians in
       1967-68
    4. Biosphere J - An experiment in Japan

Biosphere 1

   Our biosphere is divided into a number of biomes, inhabited by broadly
   similar flora and fauna. On land, biomes are separated primarily by
   latitude. Terrestrial biomes lying within the Arctic and Antarctic
   Circles are relatively barren of plant and animal life, while most of
   the more populous biomes lie near the Equator. Terrestrial organisms in
   temperate and arctic biomes have relatively small amounts of total
   biomass, smaller energy budgets, and display prominent adaptations to
   cold, including world-spanning migrations, social adaptations,
   homeothermy, estivation and multiple layers of insulation.

   For important major components of Earth's biosphere, see: Ocean;
   Forest; Desert; Steppe; Lake; River.

   Retrieved from " http://en.wikipedia.org/wiki/Biosphere"
   This reference article is mainly selected from the English Wikipedia
   with only minor checks and changes (see www.wikipedia.org for details
   of authors and sources) and is available under the GNU Free
   Documentation License. See also our Disclaimer.
