First Life:
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Although it is unclear how the majority of the water that covers the planet formed, we do know the first forms of life appeared roughly 3.5 billion years ago in the Earth’s early seas ( History Channel, 2009 ). It is important to note that these first oceans were green and nitrogen rich, unlike the oxygen rich oceans today. This is important because very few organisms, even today, can survive in nitrogen rich areas. These first Eukaryotic organisms known as “cynobactirium” were able to survive due to their unique ability to convert nitrogen into a substance that can be used to support the organism (Heldt, 1997). This process of converting or processing nitrogen is known as nitrogen fixation. This is vital to understanding the origin of green plants because these first microorganisms were also capable of splitting water in order to use the carbon dioxide just like plants today (Reece, Campbell, Cain, Urry, Minorsky, Wasserman & et al, 2011). The carbon dioxide was a key part of the survival of these organisms. However, as a result of this process, there was an enormous increase in the amount of free oxygen in the air. This influx of oxygen into the Earth’s atmosphere, coupled with the decrease in the surplus of free nitrogen, completely altered the chemical make-up of the air on earth. By doing so, conditions conducive to life were created, and in turn, the dense green seas were transformed into the rich blue oceans we know today. It is by these original photosynthetic microorganisms that all other plants and alga evolved (Reece, Campbell, Cain, Urry, Minorsky, Wasserman & et al, 2011).