The Origins of Life
The origin of life has long been a subject of much scientific debate and scientists have put forward various theories to explain how life may have begun. One such theory was advanced by Miller Urey in 1953(Moritz, 2010). Urey carried out an experiment which he assumed simulated the conditions of Primitive Earth. This experiment was referred to as ‘pre-biotic soup’ which showed how organic molecules like amino acids were formed from mixtures of water, ammonia, hydrogen, and ammonia. This experiment is controversial in that scientists are skeptical about the presence of a reducing atmosphere though several experiments have suggested that it may have been present (Moritz, 2010).
Another popular theory is the Panspermia theory, advanced by Svente Arrhenius in the early 20th century (Cruising Chemistry, 2011). This theory suggested that life’s origins did not begin on earth but was imported into earth inside a meteor. This theory has been discredited because while some studies have revealed that an organism trapped in a meteor would be safe from radiation and high temperatures. However, it would not be able to survive the long periods of time and high energy produced on impacts of meteors onto the Earth or any planetary objects (Cruising Chemistry, 2011).
A current theory advanced in 1979 after the discovery of hydrothermal vents below the ocean surface (Cruising Chemistry, 2011). These vents revealed thriving ecosystems which seemed to have survived despite the lack of solar energy. This raised questions about the possibility of these vents providing the beginnings of life. Critics have however pointed out that temperatures in these vents may have been too high. Proponents have pointed out the existence of gradients which may have provided suitable conditions; the suitability of the gradients continues to be an issue of debate.
References
Moritz A. (2010). The Origins of Life. Available at http://www.talkorigins.org/faqs/abioprob/originoflife.html
Cruising Chemistry, (2011). Possible Sites of the Origin of Life. Available at http://www.chem.duke.edu/~jds/cruise_chem/Exobiology/sites.html
