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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 ...
Earth is the only place in the universe known to harbor life, where it exists in multiple 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.
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.
All life on Earth can be traced back to a Last Universal Common Ancestor, or LUCA. A new study suggests that this organism likely lived on Earth only 400 million years after its formation. Further ...
Nevertheless, it is believed that primordial life began to evolve by the early Archean, with candidate fossils dated to around 3.5 Ga. [42] Some scientists even speculate that life could have begun during the early Hadean, as far back as 4.4 Ga, surviving the possible Late Heavy Bombardment period in hydrothermal vents below the Earth's surface ...
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 ...
Early Earth. Early Earth is loosely defined as encompassing Earth in its first one billion years, or gigayear (Ga, 10 9 y), [ 1] from its initial formation in the young Solar System at about 4.55 Ga to some time in the Archean eon in approximately 3.5 Ga. [ 2] On the geologic time scale, this comprises all of the Hadean eon, starting with the ...
The timeline of human evolution outlines the major events in the evolutionary lineage of the modern human species, Homo sapiens, throughout the history of life, beginning some 4 billion years ago down to recent evolution within H. sapiens during and since the Last Glacial Period . It includes brief explanations of the various taxonomic ranks in ...