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Oxygen loss is dominated by suprathermal methods: photochemical (~1300 g/s), charge exchange (~130 g/s), and sputtering (~80 g/s) escape combine for a total loss rate of ~1500 g/s. Other heavy atoms, such as carbon and nitrogen, are primarily lost due to photochemical reactions and interactions with the solar wind. [1] [13]
This is much faster than the expected “background” extinction rate, or the rate at which species would naturally die off without outside influence — in the absence of human beings, these 73 ...
Dresbachian extinction event: 502 Ma: End-Botomian extinction event: 517 Ma: Precambrian: End-Ediacaran extinction: 542 Ma: Anoxic event [45] Great Oxygenation Event: 2400 Ma: Rising oxygen levels in the atmosphere due to the development of photosynthesis as well as possible Snowball Earth event. (see: Huronian glaciation.)
Asteroid impacts: one large impact is associated with a mass extinction, that is, the Cretaceous–Paleogene extinction event; there have been many smaller impacts but they are not associated with significant extinctions, [105] or cannot be dated precisely enough.
In molecular biology and pharmacology, a small molecule or micromolecule is a low molecular weight (≤ 1000 daltons [1]) organic compound that may regulate a biological process, with a size on the order of 1 nm [citation needed]. Many drugs are small molecules; the terms are equivalent in the literature.
The 6th features an extinction rate between 500 and 1,000 times higher than previous extinction events. Estimates suggest that three out of four species may be gone within the next several decades.
All of them state that, provided that the physical state is held constant, the extinction process is linear in the intensity of radiation and amount of radiatively-active matter, a fact sometimes called the fundamental law of extinction. [11]
Mass transfer – Net movement of mass from one location, phase, etc. to another; Mass flux – Vector quantity describing mass flow rate through a given area; Osmosis – Migration of molecules to a region of lower solute concentration; Permeation – Penetration of a liquid, gas, or vapor through a solid