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Precambrian The Beginning of Time What is the Precambrian Time? • Earth formed about 4.6 billion years ago. • The Precambrian Time is the time the Earth was first formed. • This time is also called the beginning of life on Earth. • Earth's time is divided into four Eons, The Precambrian, Paleozoic, Mesozoic, and Cenozoic. The Precambrian, being the first Eon. Precambrian Era’s - Hadean Era -Archean Era -Proterozoic Era Hadean Era The Hadean Era was the when the Earth was first forming. Hadean is the first Era of the Precambrian time. It was the time that the solar system was forming in a cloud of dust and gas. Or commonly known as the Solar Nebula. The Solar Nebula eventually spawned planets, moons, asteroids, and comets. The Climate conditions of Hadean was very hot. Eventually into the next Era, Archean, is when Earth started to cool down. Very few terrestrial rocks are found from the Hadean Era. There was no known life forms in the Hadean Era. Archean Era The second Era of the Precambrian time is known as the Archean Era. This Era began about 4 to 2.5 billion years ago. During this time the Earth started to cool down. Torrential rain from the water from comets and hydrated minerals from the atmosphere cooled the planet and filled the first oceans with water. About 3.5 to 2.8 billion years ago living bacteria started to exist in the oceans of Archean. At the end of the Archean Era the ocean floors were covered at the bottom with living microscopic prokaryotes and bacteria. Proterozoic Era The “Age of hidden Life” or the Proterozoic Era was the last Era of the Precambrian Time. During this time major geologic changes developed and changed the Earth’s surface. Rodinia (a major geologic change) formed from plate tectonics pushing 6 upward in theo Earth’s surface. Coastal waters from Rodinia filled rounded colonies of photosynthetic algae, also known as stromatolites. During the end of the Proterozoic Era more life forms began to develop such as autotrophs and soft bodied heterotrophs. Very few fossils are found in the Proterozoic Era because most life forms were soft bodied. Eras Geologic Conditions Climate Conditions Plant/Animals Hadean Molten Materials Hot, everything was on fire. None Eras Geologic Conditions Climate Conditions Plant/Animals Archean Sheild Rock started to form and Earth started to cool down. Also plate tectonics started to form. The climate went from hot to cooler. The Earth wasn’t freezing but it did cool down quite a bit during this Era. Microscopic prokaryotes and living bacteria started to exist. Era Geologic Conditions Climate Conditions Plant/Animal Proterozoic Rodinia (a major geologic change) occurred from plate tectonics pushing upwards and structures started to form such as hills. The Climate wasn’t too hot or too cold it was in between the Archean and Hadean Era temperatures. Autotrophs and soft bodied heterotrophs existed during the end of this Era. The Enddddddddddddd URL’s for pictures http://geo.msu.edu/extra/geogmich/Precambria n.html http://www.theskepticsguide.org/the-infantearth-less-hellish-but-still-probably-not-a-funplace http://www.rockhounds.com/grand_hikes/hikes/ stromatolites_in_the_hakatai/ http://www.corzakinteractive.com/earth-lifehistory/2_archean.htm http://www.dandebat.dk/eng-klima1.htm