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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.
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 ...
The Rare Earth hypothesis argues that planets with complex life, like Earth, are exceptionally rare.. In planetary astronomy and astrobiology, the Rare Earth hypothesis argues that the origin of life and the evolution of biological complexity, such as sexually reproducing, multicellular organisms on Earth, and subsequently human intelligence, required an improbable combination of astrophysical ...
The Late Ordovician mass extinction followed the Great Ordovician Biodiversification Event (GOBE), one of the largest surges of increasing biodiversity in the geological and biological history of the Earth. [19] At the time of the extinction, most complex multicellular organisms lived in the sea, and the only evidence of life on land are rare ...
This is an accepted version of this page This is the latest accepted revision, reviewed on 6 January 2025. Problem of the lack of evidence for alien life despite its apparent likelihood This article is about the absence of clear evidence of extraterrestrial life. For a type of estimation problem, see Fermi problem. Enrico Fermi (Los Alamos 1945) The Fermi paradox is the discrepancy between the ...
It is Earth's most severe known extinction event, [10] [11] with the extinction of 57% of biological families, 83% of genera, 81% of marine species [12] [13] [14] and 70% of terrestrial vertebrate species. [15] It is also the greatest known mass extinction of insects. [16] It is the greatest of the "Big Five" mass extinctions of the Phanerozoic ...
The time value of money is the idea that receiving a given amount of money today is more valuable than receiving the same amount in the future due to its potential earning capacity.
The first eon in Earth's history, the Hadean, begins with the Earth's formation and is followed by the Archean eon at 3.8 Ga. [2]: 145 The oldest rocks found on Earth date to about 4.0 Ga, and the oldest detrital zircon crystals in rocks to about 4.4 Ga, [34] [35] [36] soon after the formation of the Earth's crust and the Earth itself.