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history of the evolution of life and the atmosphere

I have to write a short 1 and a half page essay that is a history of the evolution of life and the atmosphere from the date of the earliest atmosphere to the end of the Neogene.
What kind of evidence can I include for specific developments and both relative and absolute date information in the essay? I am also supposed to include the interrelationships of life and the atmosphere.

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This is a very complex topic. I will give you a general overview, but you will need to do some additional research to gain a complete understanding.

Earth's atmospheric composition is unique among the planets in our solar system. It is suggested that Earth has this atmosphere because of its high water content and active tectonics. These two factors gave rise to a series of events that changed Earth's original atmosphere which was rich in light elements, into the oxygen and nitrogen based one we have today.

Some scientists believe that bombardment by comets provided Earth with abundant water. The Earth gradually cooled after its formation 4.5 billion years ago, and the water liquefied to become the oceans about 4.4 billion years ago. Carbon dioxide can dissolve in water, forming a weak acid, carbonic acid. Like other rocky planets, Earth also has an abundance of carbon, iron, magnesium, and calcium. Because of the oxygen in the water, they would form metal oxides. Weathering and erosion of the primitive continents washed these into the oceans. Metal oxides are technically bases, and when combined carbonic acids they form salts. Some such salts are soluble in water, but the salts formed by combining metal oxides with carbonic acid, which are called carbonates, are insoluble. Over time, they formed a thick layer of deposits on the sea floor, where they were ...