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The solar system was a mass of swirling gas and dust. Overtime gravity pulled the gas and dust to make the sun.
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Collisions between space debris formed Earth and as more collisions occured, the larger Earth became.
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Scientists estimate the earth to be about 4 billion years old. By studing sedimentary rocks an minerals, they are able tom ake an educated guess.
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Little to no oxygen existed on earth. The first living cells were anaerobic, heterotrophic, and prokaryotes that ate organic molecules for food.
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Today stromatolite fossils have been found. Stromatolites are layered structures that form from colonies of cells.
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Scientists infer that forms of life became photosynthetic, because of chemicle evidence.
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2.2 billion years agig earth began to form to look like the earth it is today.
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Oxygen levels began to increase to what the levels are today.
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A theory suggest that a type of small aerobic prokaryote was swallowed by a larger anarerobic prokaryote and began to live inside the bigger cell. This theory is called endosymbiosis.
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Ozone is formed and it protects organisms form harmful UV Rays so they can exsist on land.
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Redi noticed the development stages of flies and performed an experiment and discovered that the theory of spontaneous regeneration was false.
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The microscope beging used mainstrem for reseach.
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Spallanzani performed an experiment, hypothesizing that microorganisms come from other microorganisms.
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Pasteur cleared up the controversy of spontaneous generation by performing an experiment. He won a prize from the Paris Academy of Science.
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Margulis developed the theory of endosymbiosis which theorized that early prokaryotic cells had a mutual relationship
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Cech discovered a kind of RNA in unicellular eukaryotes that acts as a catalyst. He referred to it as a ribozyme.
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Oparin and Haldane hypothesised that the atmosphere contained ammonia, hydrogen gas, water vapor, and carbon compounds
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Fox did extensive research cell structure. they included microspheres and coacervates.
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Miller and Ustanley rey preformed an experiment using Oparin’s hypothesis that Earth’s gases would form simple organic compounds at high temperatures.
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Radiometric dating was used to determine the age of various objects. This is completed by measuring the quantity of a specific radioactive isotope in an object.
