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A scenario is a set of related concepts pertinent to the origin of life (abiogenesis), such as the iron-sulfur world. Many alternative abiogenesis scenarios have been proposed by scientists in a variety of fields from the 1950s onwards in an attempt to explain how the complex mechanisms of life could have come into existence. These include ...
If the deep marine hydrothermal setting was the site for the origin of life, then abiogenesis could have happened as early as 4.0-4.2 Gya. If life evolved in the ocean at depths of more than ten meters, it would have been shielded both from impacts and the then high levels of ultraviolet radiation from the sun.
However, given that O 2 is a stronger absorber than CO 2, it is possible that O 2 might have an effect in situations where CO 2 is a smaller constituent in the atmosphere. [22] At such high levels, O 2 may start to have a noticeable effect on UV transmission, but at abiogenesis it is unlikely that high levels were achieved given a strong ...
[1] [2] [3] The earliest undisputed evidence of life on Earth dates from at least 3.5 billion years ago. [4] [5] [6] Evolution does not attempt to explain the origin of life (covered instead by abiogenesis), but it does explain how early lifeforms evolved into the complex ecosystem that we see today. [7]
This makes the storage of information in RNA possible in a very similar way to the storage of information in DNA. However, RNA is less stable, being more prone to hydrolysis due to the presence of a hydroxyl group at the ribose 2' position. The major difference between RNA and DNA is the presence of a hydroxyl group at the 2'-position.
It has been proposed that the early Earth hosted multiple origins of life, some of which produced chemical variations on life as we know it. [1] [2] Some argue that these alternative life forms could have become extinct, either by being out-competed by other forms of life, or they might have become one with the present day life via mechanisms like lateral gene transfer. [1]
The Great Filter is the idea that, in the development of life from the earliest stages of abiogenesis to reaching the highest levels of development on the Kardashev scale, there is a barrier to development that makes detectable extraterrestrial life exceedingly rare. [1] [2] The Great Filter is one possible resolution of the Fermi paradox. The ...
Abiogenesis is the a natural process by which life arises from non-living matter, Or to emphasize the historical question of how it happened on Earth: Abiogenesis is the natural process by which life arises arose from non-living matter, It's not your or my place to temper what we feel to be an overreaching on the part of the reliable sources.