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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 theory of panspermia speculates that life on Earth may have come from biological matter carried by space dust [92] or meteorites. [93] While current geochemical evidence dates the origin of life to possibly as early as 4.1 Ga, and fossil evidence shows life at 3.5 Ga, some researchers speculate that life may have started nearly 4.5 billion ...
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.
These timelines of world history detail recorded events since the creation of writing roughly 5000 years ago to the present day. For events from c. 3200 BC – c. 500 see: Timeline of ancient history; For events from c. 500 – c. 1499, see: Timeline of post-classical history; For events from c. 1500, see: Timelines of modern history
A variation of this analogy instead compresses Earth's 4.6 billion year-old history into a single day: While the Earth still forms at midnight, and the present day is also represented by midnight, the first life on Earth would appear at 4:00 am, dinosaurs would appear at 10:00 pm, the first flowers 10:30 pm, the first primates 11:30 pm, and ...
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.
The Origin and Nature of Life on Earth: The Emergence of the Fourth Geosphere (2016) is a book by Eric Smith and biophysicist Harold J. Morowitz which provides an introduction to origins of life research via a review of perspectives from a variety of fields active in this research area, including geochemistry, biochemistry, ecology, and microbiology.