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Global biodiversity is the measure of biodiversity on planet Earth and is defined as the total variability of life forms. More than 99 percent of all species [1] that ever lived on Earth are estimated to be extinct. [2][3] Estimates on the number of Earth's current species range from 2 million to 1 trillion, but most estimates are around 11 ...
Forests harbour most of Earth's terrestrial biodiversity. The conservation of the world's biodiversity is thus utterly dependent on the way in which we interact with and use the world's forests. [78] A new method used in 2011, put the total number of species on Earth at 8.7 million, of which 2.1 million were estimated to live in the ocean. [79]
The Earth has many diverse ecosystems and ecologicalsystem diversity. These are NASA composite images of the Earth: 2001 (left), 2002 (right), titled The Blue Marble. Ecosystem diversity deals with the variations in ecosystems within a geographical location and its overall impact on human existence and the environment.
Carbon-based life. The Lewis structure of a carbon atom, showing its four valence electrons. Carbon is a primary component of all known life on Earth, and represents approximately 45–50% of all dry biomass. [1] Carbon compounds occur naturally in great abundance on Earth.
In terms of its molecular structure, water is a small polar molecule with a bent shape formed by the polar covalent bonds of two hydrogen (H) atoms to one oxygen (O) atom (H 2 O). [32] Because the O–H bonds are polar, the oxygen atom has a slight negative charge and the two hydrogen atoms have a slight positive charge. [32]
Biogeography is the study of the distribution of species and ecosystems in geographic space and through geological time. Organisms and biological communities often vary in a regular fashion along geographic gradients of latitude, elevation, isolation and habitat area. [1] Phytogeography is the branch of biogeography that studies the ...
The remainder is consumed by animals while still alive and enters the plant-based trophic system. After plants and animals die, the organic matter contained in them enters the detritus-based trophic system. [15] Ecosystem respiration is the sum of respiration by all living organisms (plants, animals, and decomposers) in the ecosystem. [16]
Biodiversity is commonly measured in terms of taxonomic richness of a geographic area over a time interval. In order to calculate biodiversity, species evenness, species richness, and species diversity are to be obtained first. Species evenness[1] is the relative number of individuals of each species in a given area.