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At long irregular intervals, Earth's biosphere suffers a catastrophic die-off, a mass extinction, [9] often comprising an accumulation of smaller extinction events over a relatively brief period. [10] The first known mass extinction was the Great Oxidation Event 2.4 billion years ago, which killed most of the planet's obligate anaerobes.
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 ...
Frog fossils have been found on all of the Earth's continents. [ 41 ] [ 42 ] In 2020, it was announced that 40 million year old helmeted frog fossils had been discovered by a team of vertebrate palaeontologists in Seymour Island on the Antarctic Peninsula , indicating that this region was once home to frogs related to those now living in South ...
Amphibians, particularly frogs, are among the hardest hit by an extinction crisis, as are insects and reptiles. Frogs are dying off at record rates, an ominous sign the 6th mass extinction is ...
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
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They found two “olive green” frogs in the cavern and identified the animals as a known species. But “superficial” similarities gave way, and molecular analysis confirmed that these frogs ...
The earliest Earth crust probably forms similarly out of similar material. On Earth the pluvial period starts, in which the Earth's crust cools enough to let oceans form. c. 4,404 Ma – First known mineral, found at Jack Hills in Western Australia. Detrital zircons show presence of a solid crust and liquid water.