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As for life on land, in 2019 scientists reported the discovery of a fossilized fungus, named Ourasphaira giraldae, in the Canadian Arctic, that may have grown on land a billion years ago, well before plants are thought to have been living on land. [99] [100] [101] The earliest life on land may have been bacteria 3.22 billion years ago. [102]
ChemMedChem is a biweekly peer-reviewed scientific journal covering medicinal chemistry.It is published by Wiley-VCH on behalf of Chemistry Europe.In addition to original research in the form of full papers and shorter communications, the journal contains review-type articles (reviews, minireviews, patent reviews, essays, highlights) as well as occasional book reviews and conference reports.
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 ...
[10] [11] Carl Zimmer has speculated that the chemical conditions, including boron, molybdenum and oxygen needed to create RNA, may have been better on early Mars than on early Earth. [12] [13] [14] If so, life-suitable molecules originating on Mars would have later migrated to Earth via meteor ejections.
The earliest evidence for life on Earth includes: 3.8 billion-year-old biogenic hematite in a banded iron formation of the Nuvvuagittuq Greenstone Belt in Canada; [30] graphite in 3.7 billion-year-old metasedimentary rocks in western Greenland; [31] and microbial mat fossils in 3.48 billion-year-old sandstone in Western Australia.
Primordial soup, also known as prebiotic soup, is the hypothetical set of conditions present on the Earth around 3.7 to 4.0 billion years ago. It is an aspect of the heterotrophic theory (also known as the Oparin–Haldane hypothesis) concerning the origin of life, first proposed by Alexander Oparin in 1924, and J. B. S. Haldane in 1929.
The PAH world hypothesis is a speculative hypothesis that proposes that polycyclic aromatic hydrocarbons (PAHs), known to be abundant in the universe, [1] [2] [3] including in comets, [4] and assumed to be abundant in the primordial soup of the early Earth, played a major role in the origin of life by mediating the synthesis of RNA molecules, leading into the RNA world.
But the scientific literature of the early 20th century contained speculations on the origin of life. [ 15 ] [ 17 ] In 1903, physicist Svante Arrhenius hypothesized that the first microscopic forms of life, driven by the radiation pressure of stars, could have arrived on Earth from space in the panspermia hypothesis. [ 18 ]