Tag: evs - i

The biosphere is the global sum of all ecosystems, representing the zone of life on Earth. It includes all living organisms and their interactions with the lithosphere, hydrosphere, and atmosphere.

Man and biosphere programme is an international biological programme of UNESCO (United Nations Educational Scientific and Cultural Organization) which was started in 1971 but was introduced in India in 1986.

During the Hadean Eon, the early Earth was extremely hot due to frequent collisions, radioactive decay, and gravitational contraction. Estimates for the surface temperature during this formation period are typically in the range of 5000 to 6000 degrees Celsius.

Ozone in the stratosphere absorbs ultraviolet radiation from the sun, which converts that energy into heat. This process makes the stratosphere warmer by approximately 53 degrees Celsius compared to the temperature at the tropopause.

The Earth is differentiated into the crust, mantle, and core. The crust is the outermost, thin, solid layer of the planet.

The terrestrial planets are the four inner planets of the solar system: Mercury, Venus, Earth, and Mars. They are characterized by their solid, rocky surfaces.

Hydrogen is the most abundant element in the Sun, making up about 73% of its mass. Helium is second at about 25%, with other elements like carbon and oxygen being trace components.

The primary atmosphere of the early Earth was reducing, meaning it contained hydrogen-rich gases like methane and ammonia, and lacked free oxygen.

As the Earth cooled and the atmosphere evolved, atomic gases (which were unstable) and free oxygen (which was highly reactive) were largely absent or consumed in chemical reactions. Both are considered to have been absent or disappeared during the transition.

Cyanobacteria, also known as blue-green algae, were the first organisms to perform oxygenic photosynthesis. This process released oxygen as a byproduct, eventually leading to the Great Oxidation Event.