Even as attempts to resolve the origin of life paradox still persists, the spontaneous generation hypothesis is still worth mentioning as one of the most famous hypotheses about the origin of life. According to the spontaneous generation hypothesis, there was a possibility that life could have sprouted from organic matter under the influence of unknown forces. As Simon, Dickey and Reece document, it was widely believed for instance that flies could arise from rotting meat just as fish could spontaneously arise from ocean mud (296). The spontaneous generation hypothesis was famous because it blended remarkably well with the theory of creationism which upheld that life could just spout from something- it is believed in creationism that God created living things from mad, and in some instances he just gave orders and “things” came into existence. However, the spontaneous generation hypothesis was disapproved by Louis Pasteur who discovered that life can only arise by a reproduction of preexisting life (Simon, Dickey and Reece 296). Nonetheless, it cannot be proved that spontaneous generation is still occurring or can still occur today. Many researchers explain that the spontaneous generation was necessitated with the absence of oxygen (which is a remarkably strong oxidizing agent); this gives insight as to the reason why spontaneous generation cannot occur today.
Also famous is the four-stage hypothesis of the origin of life in which life is believed to have originated from chemical molecules that became aggregated and finally were able to replicate and metabolize (Simon, Dickey and Reece 296). According to the four-stage hypothesis, the first and crucial stage with regards to the beginning of lie was abiotic synthesis of small organic monomers such as nucleotides and amino acids (stage 1). The monomers formed in stage 1 would then be joined together in stage 2 to form polymers such as proteins. Stage three of the four-stage hypothesis, as documented by Simon, Dickey and Reece, involved the formation of pre-cells (298). It is worth emphasizing that the products of the third stage are called pre-cells and not cells because they are simply molecular packages with certain properties of life (Simon, Dickey and Reece 298). The pre-cells formed in stage three give rise to replicating molecules in fourth and the last stage particularly in fulfillment of the fact that life is partially defined by the process of inheritance (Simon, Dickey and Reece 298). It should be noted that the plausibility of this hypothesis is fostered by several experimental findings. For instance, it has since been proven that RNA molecules can spontaneously assemble from nucleotides with any enzymatic influence (Simon, Dickey and Reece 298). On the same note, the concept of abiotic synthesis has also been proven with the production of all the 20 amino acids, in addition to several sugars, from laboratory analogs of the primeval earth.
Concisely, the origin of life is still a big paradox. Scientists have greatly tried to explain the origin of life leading to the formulation of several hypotheses. One thing that still remains eminent is the construct that the origin of life is still yet to be unequivocally underpinned.
Simon, Eric J., Jean L. Dickey, and Jane B. Reece. Campbell Essential Biology, Fourth Edition. San Francisco: Benjamin Cummings, 2010. Print.