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Earth and the other planets of the solar system formed, condensing from a vast cloud of dust and roach that surrounded the young sun.
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Multiple the year by 1,000,000 to find the correct year.
Example:
4,530 BCE --> 4,530,000,000 BCE or 4.53 Billion BCE -
Oldest known rocks on Earth’s surface, located at a site called Issua in Greenland, existed.
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Fragments of a 4.5-billion-year-old chondrite collected in southern Australia containing more than 80 amino acids shows that first life on Earth may have come from space.
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Earth began to cool to a temperature at which liquid water could exist, and thus life could exist.
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First life may have developed in undersea alkaline vents
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Oldest known fossils, fossils of stromatolites, come into existence
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The first cells began to use the sun's energy and convert it into their own energy.
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Some single-celled organisms may be feeding on methane by this time.
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Supposedly, the poisonous waste produced by photosynthetic cyanobacteria – oxygen – started to build up in the atmosphere. Dissolved oxygen makes the iron in the oceans “rust” and sink to the seafloor, forming striking banded iron formations and making life more viable.
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Earth freezes over in what may have been the first “snowball Earth”, possibly as a result of a lack of volcanic activity. When the ice eventually melts, it indirectly leads to more oxygen being released into the atmosphere.
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Eukaryotes divide into three groups
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Animal phyla originated and began to diverge, showing the creation of varying species and new animals.
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First they divide into, essentially, the sponges and everything else – the latter being more formally known as the Eumetazoa.
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The planet freezes over again in another “snowball Earth“.
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Severe ice age occurred, reducing the speed at which life was being formed.
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The comb jellies (ctenophores) split from the other multicellular animals.
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The ancestor of cnidarians (jellyfish and their relatives) breaks away from the other animals – though there is as yet no fossil evidence of what it looks like.
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Around this time, some animals evolve bilateral symmetry for the first time
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The Bilateria, those animals with bilateral symmetry, undergo a profound evolutionary split. They divide into the protostomes and deuterostomes.
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Fossilised animal trails suggest that some animals are moving under their own power.
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The Cambrian explosion was the relatively short evolutionary event, beginning around 541 million years ago in the Cambrian period, during which most major animal phyla appeared, as indicated by the fossil record.
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The first true vertebrate – an animal with a backbone – appears. It probably evolves from a jawless fish that has a notochord, a stiff rod of cartilage, instead of a true backbone. The first vertebrate is probably quite like a lamprey, hagfish or lancelet.
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Macroscopic life in the form of plants, fungi, and animals did not colonize land until about 500 million years ago. This gradual evolutionary venture was associated with adaptations that helped prevent dehydration and made it possible to reproduce on land.
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The Great Ordovician Biodiversification Event begins, leading to a great increase in diversity. Within each of the major groups of animals and plants, many new varieties appear.
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Plants begin colonizing the land.
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Pneumodesmus newmani is a species of millipede that lived 428 million years ago, in the Late Silurian. It is the first myriapod, and the oldest known creature to have lived on land.
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The first four-legged animals, or tetrapods, evolve from intermediate species such as Tiktaalik, probably in shallow freshwater habitats. The tetrapods go on to conquer the land, and give rise to all amphibians, reptiles, birds and mammals.
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The first major groups of amphibians developed in the Devonian period, around 370 million years ago, from lobe-finned fish which were similar to the modern coelacanth and lungfish. These ancient lobe-finned fish had evolved multi-jointed leg-like fins with digits that enabled them to crawl along the sea bottom.
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The Permian period ends with the greatest mass extinction in Earth’s history, wiping out great swathes of species, including the last of the trilobites.
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By the year 200,000,000 BCE, dinosaurs reigned through and ruled throughout the entire world, being the dominant inhabitiants of Earth.
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A half-feathered, flightless dinosaur called Epidexipteryx, which may be an early step on the road to birds, lived in China.
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The first flowering plants emerge, following a period of rapid evolution.
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The oceans become starved of oxygen, possibly due to a huge underwater volcanic eruption. Twenty-seven percent of marine invertebrates are wiped out.
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By the year 65,000,000 BCE, all dinosaurs had gone extinct. According to scientists who maintain that dinosaur extinction came quickly, the impact must have spelled the cataclysmic end.
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New World monkeys become the first simians (higher primates) to diverge from the rest of the group, colonizing South America.
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Gorillas branch off from the other great apes.
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Humans diverge from their closest relatives; the chimpanzees and bonobos.
