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Unformatted text preview: Ancient Life Earth came into existence about 4.6 billion years ago, and about 3.8 billion years ago, the evolution of chemicals began. Scientists estimate that at about 3.5 billion years ago, the first cells were in existence. Scientists believe that the first cells lived within the organic environment of the earth and used organic foods for their energy. The type of chemistry in those first cells was somewhat similar to fermentation, which uses organic molecules, such as glucose. The energy yield, although minimal, is enough to sustain living things. However, organic material would soon have been used up if this were the sole source of nutrition, so a new process had to develop. The evolution of a pigment system that could capture energy from sunlight and store it in chemical bonds was an essential breakthrough in the evolution of living things. The organisms that possess bonds was an essential breakthrough in the evolution of living things....
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This note was uploaded on 11/11/2011 for the course BIO 101 taught by Professor Pesthy during the Fall '07 term at Texas State.
- Fall '07