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The first known mass extinction was the Great Oxidation Event 2.4 billion years ago, which killed most of the planet's obligate anaerobes. Researchers have identified five other major extinction events in Earth's history, with estimated losses below: [ 11 ]
Geologic time is the timescale used to calculate dates in the planet's geologic history from its origin (currently estimated to have been some 4,600 million years ago) to the present day. Radiometric dating measures the steady decay of radioactive elements in an object to determine its age. It is used to calculate dates for the older part of ...
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
This clickable timeline template, wikilinked to over 30 Wikipedia articles, translated into over 30 languages, edited by over 110 editors, transcluded to over 100 articles, was originally derived from {{Life timeline}} for inclusion in the article "Timeline of the evolutionary history of life".
From roughly 230-200 million years ago, during the Late Triassic and into the early Jurassic periods, dinosaurs emerged from just one of many reptilian species to become the dominant species on Earth.
Birds were therefore the only dinosaur lineage to survive the Cretaceous–Paleogene extinction event approximately 66 million years ago. Dinosaurs can be divided into avian dinosaurs (birds) and non-avian dinosaurs, which are all dinosaurs other than birds. Birds are feathered theropod dinosaurs and constitute the only known living dinosaurs.
A mass extinction event that brought about the rise of the dinosaurs more than 200 million years ago was believed to be caused by the planet’s warming. Now, scientists at Columbia University say ...
Scholars deciphered inscriptions on 4,000-year-old tablets more than 100 years after they were originally discovered. ... may have looked like 2,000 to 4,500 years ago, according to George. “In ...