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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 age of Earth is about 4.54 billion years; [7] [33] [34] the earliest undisputed evidence of life on Earth dates from at least 3.5 billion years ago according to the stromatolite record. [35] Some computer models suggest life began as early as 4.5 billion years ago. [36] [37] The oldest evidence of life is indirect in the form of isotopic ...
Earth's surface temperature will reach around 420 K (147 °C; 296 °F), even at the poles. [78] [94] 2.8 billion High estimate until all remaining Earth life goes extinct. [78] [94] 3–4 billion The Earth's core freezes if the inner core continues to grow in size, based on its current growth rate of 1 mm (0.039 in) in diameter per year.
The remains or traces of organisms from a past geologic age embedded in rocks by natural processes are called fossils. They are extremely important for understanding the evolutionary history of life on Earth, as they provide direct evidence of evolution and detailed information on the ancestry of organisms.
A mineral grain from a meteorite preserved evidence that water was present on Mars 4.45 billion years ago, and it may have created hot springs habitable for life. ‘Black Beauty’ was found on ...
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.
In geochronology, time is generally measured in mya (million years ago), each unit representing the period of approximately 1,000,000 years in the past. The history of Earth is divided into four great eons, starting 4,540 mya with the formation of the planet. Each eon saw the most significant changes in Earth's composition, climate and life.