bis2amidterm1

bis2amidterm1 - energy such as light from the sun Contrary...

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Midterm I Take-Home Essay TA: Xuan Heterotrophic vs. Autotrophic A heterotrophic organism requires an outside source, such as organic substrates, to obtain its carbon for growth and development. Heterotrophs are known as consumers on the food chain and make up all of the animals on earth. It is proposed that the first life on earth was a “primordial soup”; rich in organic compounds and containing most of the molecules that life needed to begin. However, this “primordial soup” hypothesis requires a highly reducing atmosphere which did not entirely exist as some researchers say. This leads to another hypothesis about how life began: an autotrophic beginning in which carbon dioxide, the autotrophic main ingredient, is abundant. An autotroph produces organic compounds from simpler inorganic molecules. It needs an external source of
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Unformatted text preview: energy, such as light from the sun. Contrary to heterotrophs, autotrophs are producers in the food chain and can carry out photosynthesis. It would have been easy for autotrophs to reproduce and thrive in a neutral atmosphere since they don’t require an external source of substrates for growth. I believe it is highly unlikely that a “primordial soup” appeared containing all of the essential compounds for heterotrophs to evolve. It seems much more likely that autotrophs arose first and created the organic-rich compound of the “primordial soup”. Although neither of these hypothesis have been proven correct (or wrong), I believe the first life was autotrophic because of the simpler method to gathering ingredients for producing organic compounds....
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This note was uploaded on 05/23/2008 for the course BIS 2A taught by Professor Grossberg during the Winter '08 term at UC Davis.

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