03.10.2014

Plan       Structure and limits of the biosphere. V.I. Vernadsky’s concept of the biosphere . Autotrophic and heterotrophic organisms. Producers, consumers, decomposers. Energy flow.

Evolution of the biosphere.

BIOSPHERE

• • Biosphere is defined as that part of the Earth in which living organisms exist. The sum of all ecosystems.

• • Eduard Suess, 1875 - The term ‘biosphere’ ‘The place on earth's surface where life dwells’.

• • V.I. Vernadsky “The Biosphere” (1926)

Earth Planet

internal geospheres:  core  mantle external geospheres:  lithosphere    hydrosphere atmosphere biosphere • • • Weight: 6∙10 21 tons Volume: 1,083∙10 12 km 3 Surface area: 510,2∙10 6 км 2

External geospheres

σφαϊρα – sphere Lithosphere λίθος – rocky, stone Hydrosphere ὕδωρ – water Atmosphere ἀτμός – air, vapor Biosphere Βίος - life

The parts of the biosphere

 Aerobiosphere  Hydrobiosphere  Lithobiospere  Terrabiosphere 

Two categories of layers

 1 eubiosphere that part of the biosphere in which the physiological processes of living organisms can occur  2 – parabiosphere - that part of biosphere which is not inhabited by living things and is harsh to life

The upper limit of life in biosphere

• The ozone layer is a barrier to strong ultraviolet (UV) radiation from the Sun and space radiation, which is disastrous for all living things • • The ozone protective layer is situated at 15–50 km of altitude. The height of the ozone layer at the poles: 7-8 km , at the equator: 17-15 km, • • • the height of the highest concentrations of ozone: 22-26 km, the maximum height, where ozone is found: 45-50 km.

4  10 –7 vol. %

Ozone altitude UV graph

UV-A (315–400 nm) UV-B (280–315 nm) UV-C (100–280 nm)

O 3

(200–280 nm)

The lower limit of life in the biosphere

   10–15 km below sea level in the ocean 3–3.5 km into the Earth's crust The lower limit of life in the biosphere is defined by temperature: 100 °C at a depth 3–3.5 km  The biosphere has the overall dimension of a hollow sphere some 23 km wide. This yields about 0.0007 % of the volume of the planet, which has a 6371 km radius.

V.I. Vernadsky’s concept of the biosphere

 a complete theory about the biosphere of the planet Earth.     He specified boundaries (limits) of the biosphere, defined the difference of living and non-living matter, determined the total mass of living matter,  calculated the amount of cosmic energy that is absorbed by the biosphere, determined cycles of chemical elements passing through living organisms of the biosphere, etc.

The components of the matter of the biosphere

1) 2) 3) 4) 5) 6) 7) living matter, biogenic matter, inert matter, bioinert matter, radioactive matter, dispersed atoms, matter of cosmic origin.

1 Living matter

 Living matter – the Earth's sum total of living organisms: plants, animals and microorganisms.

 Living matter transforms the radiant energy of the sun into the active chemical energy of the biosphere.

 Living matter as a biogeochemical factor is expressed quantitatively in elementary chemical composition, mass, and energy.

The total mass of living organisms ~ 2,42∙10 12 т ~ 97 % plants ~ 3 % animals and microorganisms

Biogeochemical functions of living component

  Gaseous: migration of gases and their transformations Concentration: selective accumulation of some chemical elements from the external environment by living organisms  Oxidation-reduction: chemical transformations of substances containing atoms with variable valence – compounds of iron, manganese, trace elements  Biogeochemical activity of humans

The components of the matter of the biosphere

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Inert matter or ‘kosnoe’. It is nonliving matter which is formed without the participation of living organisms: magmatic rocks.

Bioinert matter. It is the structure of living and inert matter, which is created by living organisms and nonliving processes: soil Biogenic matter. It is the substance that appeared as a result of the decomposition of the living organisms’ remains, but not yet fully mineralized: coal, oil, peat, etc.

Radioactive matter - the substance in the radioactive decay in the form of relatively stable radioactive elements.

Dispersed atoms that are continually created from all sorts of earthly substance under the influence of cosmic radiation.

Matter of cosmic origin, coming to the surface of the Earth from space: meteorites, cosmic dust.

V.I. Vernadsky’s concept of the biosphere

1.

The planetary geochemical role of living matter – that is, the totality of all living organisms that have existed or still exist in a given time segment, which are regarded as a powerful geologic factor.

2.

The complex transformation of matter-energy and informational flows by living matter during the geologic history of the earth.

Autotrophic and heterotrophic organisms

 An autotroph is an organism that produces complex organic compounds from simple substances present in its surroundings, using energy from light (photosynthesis) or inorganic chemical reactions (chemosynthesis).

 Greek αύτός - ‘self’ and τροφή - ‘nutrition’   A heterotroph is an organism that cannot fix carbon and uses organic carbon from other organisms for growth. Greek ἕ τερος - ‘another’, ‘different’ and τροφή - ‘nutrition’.

Classification of living matter on ecological function

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producers;

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consumers;

3.

decomposers.

Producers

 A producer is an autotrophic organism typically a photosynthetic green plant that synthesizes organic matter from inorganic materials. Producers make energy for themselves and often provide food for other organisms.

Consumers

 A consumer is an organism that receives energy by consuming other organisms. Consumers are formally referred to as heterotrophs.  There are three types of consumers: herbivores carnivores omnivores

Decomposers

 A decomposer is an organism that breaks down dead or decaying organisms, and in doing so carry out the natural process of decomposition. Decomposers are heterotrophic.  These can be fungi, animals, bacteria, etc.

The scheme showing the flows of matter and energy in the biosphere

Photosynthesis

6CO 2 + 6H 2 O (+ light energy) → C 6 H 12 O 6 + 6O 2

 Photosynthesis is the process of converting light energy to chemical energy and storing it in the bonds of sugar. This process occurs in plants and some algae. Plants need only light energy, CO 2 , and H 2 O to make sugar. The photosynthesis takes place in the chloroplasts, specifically using chlorophyll, the green pigment involved in photosynthesis.

Evolution of the biosphere

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Creationism Theory of stationary state Theory of spontaneous generation Panspermia theory Biochemical evolution

Biochemical evolution theory of life

   Alexander Oparin (in 1924) and John Haldane (in 1925) The molecular or chemical evolution theory of life The first molecules constituting the earliest cells “were synthesized under natural conditions by a slow process of molecular evolution, and these molecules then organized into the first molecular system with properties with biological order”.

5 bya - the origin of solar system

4.6-4.5 bya – formation of the Earth

3.8 bya - the liquid oceans formed

Synthesis of organic monomers

an oxygenless atmosphere

Miller’s experiment, 1953

In the atmosphere, composed primarily of CH 4 , NH 3 , H 2 O, H 2 S, CO 2 or CO, electrical activity can catalyze the creation of certain basic small molecules (monomers) of life, such as amino acids.

 The formation of organic polymers and genetic material from the existing monomers.

 These compounds accumulated in a “primordial soup”.

Coacervate droplets

These droplets would “grow” by fusion with other droplets, and “reproduce” through fission into daughter droplets, and so have a primitive metabolism

Prokaryotes and eukaryotes

    

4.1 to 3.5 bya

The first prokaryotes, like cyanobacteria, came into existence.

They emitted oxygen as a waste product.

1.7-2.5 bya

Eukaryotes organisms whose cells have a well defined membrane bound nucleus and organelles

Water is the first medium of life on Earth

 Life could exist in an oxygen-free atmosphere only under the protection of the water layer. Water layer thickness of 2-3 m absorbs hard radiation like the ozone layer.  Thus, the ancient biosphere arose in the hydrosphere, existed within it and had heterotrophic nature.

Atmospheric oxygen levels over geological time

1.

Atmospheric oxygen levels increased 2.3 bya to a level 1% of the atmosphere. 2.

about 600 million years ago to a level 21%. © Snowball Earth.org.

540 million years ago Cambrian Explosion happened: multicellular animals' “big bang” Rising atmospheric and oceanic oxygen levels promoted the development of larger animals, which need more oxygen than small ones in order to move blood throughout their bodies .

The first multicellular animals appeared about 575 million years ago were soft-bodied

Появляются губки, кораллы, черви, моллюски.

The second medium of life is formed – a living organism (parasite).

Land plants emerged between about 500 and 400 million years ago. By creating shade, they also provided habitat for the first amphibians to move from water to land.

The formation of two media of life happens: the soil and the terrestrial environment.

Dinosaurs evolved about 215 million years ago

The first flowering plants, small mammals, and the first birds appeared in this period

65 million years ago a giant asteroid killed the dinosaurs

Thus, within the biosphere four living environment formed:

• • • • water (non-living medium ) air (non-living medium ) soil (bioinert medium ) living organism (living medium )

 Human evolution occurred and opened the social stage of evolution of the biosphere.

 Vernadsky defined the future evolutionary state of the biosphere as the noosphere, the sphere of reason, the “sphere of human thought".

Noosphere

   The biosphere, controlled by human mind, is called noosphere. “Sphere of human thought” French mathematician and philosopher, Edouard Le Roy the term “noosphere” (1927)  In Vernadsky's interpretation, the noosphere, is a new evolutionary stage of the biosphere, when human reason will provide further sustainable development both of humanity and the global environment.