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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.
6000 BC: Evidence of habitation at the current site of Aleppo dates to about c. 8,000 years ago, although excavations at Tell Qaramel, 25 kilometres (16 mi) north of the city show the area was inhabited about 13,000 years ago, [124] Carbon-14 dating at Tell Ramad, on the outskirts of Damascus, suggests that the site may have been occupied since ...
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 ...
Dinosaurs are a diverse group of reptiles [note 1] of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is a subject of active research.
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 ...
What type of dinosaur it belonged to is unknown, but there have been suggestions that it was from Allosaurus. "Beelemodon": Known only from two teeth found in Wyoming. They share features of compsognathids, dromaeosaurids and basal oviraptorosaurs. "Capitalsaurus": The official dinosaur of the District of Columbia. It is known from a single ...