endosymbiosis
Scientists have formulated many theories about the origin of life and how it evolved into the various forms known today. These ideas come from the evidence of the fossil record, from laboratory simulations of conditions on the earth, and from consideration of the structure and function of cells.The earth was created more than 4 billion years ago, although more than 2 billion years probably passed before life was developed. Scientists believe that the atmosphere of the young earth was mostly water vapor, methane, and ammonia, with very little gaseous oxygen. Laboratory simulations have shown that all major classes of organic molecules could have been generated from this atmosphere by the energy of the sun or by lightning and that the lack of oxygen would prevent newly formed organic molecules from being broken down by oxidation. Randomly formed aggregations that could harness energy to grow and reproduce themselves would eventually far outnumber other combinations. DNA may have been an important component of the self-reproducing aggregates and RNA is the only organic molecule able to duplicate themselves. The absence of oxygen from the atmosphere of the young earth meant that no ozone layer existed to screen out ultraviolet rad
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Some common words found in the essay are:
, Academy Sciences, Professor Jeon, DNA RNA, mitochondria chloroplasts, eukaryotic cells, University Tennessee, cells cells, host cell, protein synthesis, cells cells nuclei, mitochondria chloroplasts own, resembles prokaryotes, evolved symbiotic relationship, genetic material, structures eukaryotic, atmosphere earth, similar prokaryotic,
Approximate Word count = 1045
Approximate Pages = 4 (250 words per page double spaced)
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