The Origin of Life

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The Origin of Life

        Life has been around for a long time on earth. Scientists believe that the conditions on Earth were suitable for life to evolve some 3,800,000,000 years ago. That seams like a long time and if we compare that to the date we believed the earth was formed, 4,600,000,000 years ago, we find that for most of earth’s history some form of life has been around. The earliest fossils found on Earth indicate to us that life was present 3,500,000,000 years ago, but this life was only in the form of simple cellular life, no sign of the large multicellular organisms found in this time period. The question is; how did this life come to exist at all? What was the origin of life on Earth?

        To answer this question we need to know more about the environment this early life was living in. Scientists have looked at the moon and seen the craters that exist there. Why are there no such craters on Earth? The answer to that is, there are craters on earth. They have just either been worn away by natural processes or are hidden under the ocean. This means that early earth must have been bombarded by comets, creating a highly hostile environment. This brings us to the first theory as to the origins of life on earth. As so many meteorites were colliding with the earth, it is not impossible to assume that several of these meteorites may have contained elements not found in abundance on earth at this time. Comets found in recent years have yielded many elements that were not thought to have existed in such abundance. So, could this have been the method of ‘seeding life’ onto the planet Earth? There is great debate as to this theory, which is called panspermia. In modern day meteorites extraterrestrial organic compounds, including amino acids, have been found. Biochemists recently demonstrated that organic molecules extracted from meteorites produced small vesicles when mixed with water. We have not yet seen any evidence of life existing anywhere else in the universe, so it may be safe to assume that these comets didn’t play a pivotal role in the evolution of life.

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        Other early environmental events include the formation of the oceans. Vast expanses of water were formed in a relatively short time period. Scientists have uncovered evidence, which suggests that life started in the oceans. There were layers of tar protecting the oceans from the intense UV rays that the sun released. Within the oceans, there was a mixture of Amino acids, sugars, porphyrins and other unknown substances. Scientists of today have recreated this ‘soup’ to the best of their ability, and have found that the results were very encouraging. Life didn’t spring forth, but they were close. So, if this ...

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