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Nitrogen is a chemical element; it has symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at seventh in total abundance in the Milky Way and the Solar System.
Mesquite is a common name for some plants in the genus Prosopis and Neltuma, both of which contain over 40 species of small leguminous trees. They are native to dry areas in the Americas. They have extremely long roots to seek water from very far under ground. As a legume, mesquites are one of the few sources of fixed nitrogen in the desert ...
The history of life on Earth traces the processes by which living and extinct organisms evolved, from the earliest emergence of life to the present day. Earth formed about 4.5 billion years ago (abbreviated as Ga, for gigaannum) and evidence suggests that life emerged prior to 3.7 Ga. [1] [2] [3] The similarities among all known present-day species indicate that they have diverged through the ...
One ancient view of the origin of life, from Aristotle until the 19th century, is of spontaneous generation. [19] This theory held that "lower" animals such as insects were generated by decaying organic substances, and that life arose by chance. [20] [21] This was questioned from the 17th century, in works like Thomas Browne's Pseudodoxia ...
Nitrogen assimilation is the formation of organic nitrogen compounds like amino acids from inorganic nitrogen compounds present in the environment. Organisms like plants, fungi and certain bacteria that can fix nitrogen gas (N 2) depend on the ability to assimilate nitrate or ammonia for their needs. Other organisms, like animals, depend ...
Soil atmosphere is also the seat of emissions of volatiles other than carbon and nitrogen oxides from various soil organisms, e.g. roots, [76] bacteria, [77] fungi, [78] animals. [79] These volatiles are used as chemical cues, making soil atmosphere the seat of interaction networks [ 80 ] [ 81 ] playing a decisive role in the stability ...
The nitrogen cycle is an important process in the ocean as well. While the overall cycle is similar, there are different players [40] and modes of transfer for nitrogen in the ocean. Nitrogen enters the water through the precipitation, runoff, or as N 2 from the atmosphere. Nitrogen cannot be utilized by phytoplankton as N
Species go extinct constantly as environments change, as organisms compete for environmental niches, and as genetic mutation leads to the rise of new species from older ones. At long irregular intervals, Earth's biosphere suffers a catastrophic die-off, a mass extinction , [ 9 ] often comprising an accumulation of smaller extinction events over ...