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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 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 thin disk of our galaxy began to form when the universe was about 5 billion years old or 9 ± 2 Gya. [15] The Solar System formed at about 9.2 billion years (4.6 Gya), [5]: 22.2.3 with the earliest evidence of life on Earth emerging by about 10 billion years (3.8 Gya).
Big History covers the formation of the universe, stars, and galaxies, and includes the beginning of life as well as the period of several hundred thousand years when humans were hunter-gatherers. It sees the transition to civilization as a gradual one, with many causes and effects, rather than an abrupt transformation from uncivilized static ...
Despite this precaution, the issue featured prominently in the debate that followed the book's publication. For most of the first half of the 19th century, the scientific community believed that, although geology had shown that the Earth and life were very old, human beings had appeared suddenly just a few thousand years before the present.
The Rare Earth hypothesis argues that planets with complex life, like Earth, are exceptionally rare.. In planetary astronomy and astrobiology, the Rare Earth hypothesis argues that the origin of life and the evolution of biological complexity, such as sexually reproducing, multicellular organisms on Earth, and subsequently human intelligence, required an improbable combination of astrophysical ...
[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 ...