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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 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 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.
Earth is the only place in the universe known to harbor life, where it exists in myriad environments. [8] [9] The origin of life on Earth was at least 3.5 billion years ago, possibly as early as 3.8-4.1 billion years ago. [2] [3] [4] Since its emergence, life has persisted in several geological environments.
All life on Earth can be traced back to a Last Universal Common Ancestor, or LUCA—and it likely lived on Earth only 400 million years after its formation. ... Life on Earth had to begin ...
The origin of life is related to organic chemistry, some of which is preserved in these rocks from 4.5 billion years ago," said astrobiologist and study co-author Jason Dworkin, the OSIRIS-REx ...
Starting in 1985, researchers proposed that life arose at hydrothermal vents, [235] [236] that spontaneous chemistry in the Earth's crust driven by rock–water interactions at disequilibrium thermodynamically underpinned life's origin [237] [238] and that the founding lineages of the archaea and bacteria were H 2-dependent autotrophs that used ...
For decades, scientists have theorized that volcanic lightning on an early Earth played a crucial role in kickstarting life on the planet by breaking molecules into useful, biological components.