Abiogenesis - Scientific Essay

Abiogenesis

 Scientific Essay

    How and when did life on Earth start? Although it is believed that Earth has formed about 4.54 billion years ago, these questions remained mysteries for thousands of years in human history (Said, 2003). One of the speculations presented as an evolutionary process is abiogenesis.

    As defined, abiogenesis, also termed as biopoiesis, is the process of life arising from non-living matter such as simple organic compounds (Planetary Sciences, Inc., 2019). Life started from inorganic molecules which recombined in various ways due to energy input. Said (2003) also added that it is a scientific theory which posits that life arose on Earth through spontaneous natural means due to conditions present at that time. Thus, life came from non-living matter. Abiogenesis proposes that the first life-forms generated were very simple and through a gradual process, they became increasingly complex. Spontaneous generation was an early model for abiogenesis established by Aristotle (384-322 BCE) which said that logs gave rise to crocodiles, mice come from mud, maggots from rotting meat and flies formed directly from decaying material. In the mid-1800s, experimentations by Louis Pasteur disproved spontaneous generation since that time, scientists have been working to describe more probable models of abiogenesis which could explain the formation of life (Biologydictionary.net., 2017).

    As evidence to prove abiogenesis, Alexander Oparin and John Burdon Sanderson Haldane were the first scientists to propose a chemical-based theory for the evolution of life in the 1920s called the Primordial Soup Theory. They postulated that Earth’s early atmosphere had mostly carbon dioxide, water, ammonia, hydrogen sulfide, and phosphate with very minute oxygen. The atmosphere was gradually reducing, capable of accepting electrons and creating new molecules. Under these primitive conditions, energy sources such as lightning, ultraviolet radiation, or even impact shock could form organic molecules like amino acids. The work of Oparin and Haldane laid the groundwork for other researchers to test these hypotheses.

    The evolutionary theory of abiogenesis was given much credit to Stanley Miller and Harold Urey in 1953. They collectively combined various gases that were thought to exist in the early phases of Earth. These gases were combined in a chamber and shocked with electricity. After trials, they found that the molecules had begun the process of combining into more advanced molecules. They, therefore, theorized that over billions of years, molecules could combine into self-replicating versions, such as RNA and DNA. Note that while abiogenesis and evolution are linked, they are dissimilar as evolution says nothing about how life began; abiogenesis says nothing about how life evolves.

            

References:

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Encyclopedia Britannica (2017). Abiogenesis. Retrieved from https://www.britannica.com/science/abiogenesis.

Biologydictionary.net. (2017) Evidence for abiogenesis. Retrieved from: https://biologydictionary.net/evidence-for-abiogenesis/

Planetary Sciences, Inc. (2019) Theory of abiogenesis. Retrieved from: https://planetary-science.org/astrobiology/thoery-of-abiogenesis/

Said, J. (2003) Abiogenesis: Definition, theory, and evidence. Retrieved from: https://study.com/academy/lesson/abiogenesis-definition-theory-evidence.html