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Cells resembling prokaryotes appear. [29] These first organisms are believed to have been chemoautotrophs, using carbon dioxide as a carbon source and oxidizing inorganic materials to extract energy. 3800 Ma Formation of a greenstone belt of the Isua complex in western Greenland, whose isotope frequencies suggest the presence of life. [28]
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.
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 ...
23 kya – 21 kya: The earliest known human footprints in North America are left at what is now White Sands National Park, New Mexico. [69] 21 kya: Artifacts suggest early human activity occurred in Canberra, the capital city of Australia. [70] 20 kya: Kebaran culture in the Levant: beginning of the Epipalaeolithic in the Levant. [71]
A new comparison of the human and chimpanzee genomes suggests that after the two lineages separated, they may have begun interbreeding... A principal finding is that the X chromosomes of humans and chimpanzees appear to have diverged about 1.2 million years more recently than the other chromosomes. The research suggests:
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 ...
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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 ...