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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 ...
A secondary palate enables the animal to eat and breathe at the same time and is a sign of a more active, perhaps warm-blooded, way of life. [21] They had lost gastralia and, possibly, scales. 260-230 Ma Cynognathus. One subgroup of therapsids, the cynodonts, lose pineal eye and lumbar ribs and very likely became warm-blooded.
The theory of panspermia speculates that life on Earth may have come from biological matter carried by space dust [93] or meteorites. [94] 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 ...
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 ...
Starting in 1985, researchers proposed that life arose at hydrothermal vents, [237] [238] that spontaneous chemistry in the Earth's crust driven by rock–water interactions at disequilibrium thermodynamically underpinned life's origin [239] [240] and that the founding lineages of the archaea and bacteria were H 2-dependent autotrophs that used ...
Pieces of 4.5-billion-year old space rock will tell us where we came from, scientists hope
[4] [5] Charles Darwin more famously proposed the theory of universal common descent through an evolutionary process in his book On the Origin of Species in 1859: "Therefore I should infer from analogy that probably all the organic beings which have ever lived on this earth have descended from some one primordial form, into which life was first ...