The origin of life is one of the most interesting and challenging problems facing scientists today. To determine the true nature of the origin of life would conclude ongoing curiosity. Abiogenesis is the idea that life developed from non-life over 3.5 billion years ago. The idea theorises that the first lifeforms created were simple organisms, but that they slowly increased in complexity.
The context of abiogenesis
Life on Earth is created from four key biomolecules. These are lipids, carbohydrates, amino acids, and nucleic acids. One such nucleic acid is called RNA, and this can act as genetic material and a catalyst. Therefore, it is proposed that primitive life was RNA-based and that the emergence of life from non-life was a gradual process. A process that is not known to have been repeated since.
From the simple life forms, more complex organisms developed and diversified. The primordial cells adapted to their surroundings and evolved through the expansion of both physical and genetic features. Genomes were duplicated, alongside the addition of mutations. It is thought that this development began with archaeal and prokaryotic bacteria. Darwinian natural selection came into play, and evolution began.
Evidence for abiogenesis
Scientists have discovered geochemical evidence of the environmental conditions of the primitive Earth, experienced by early life forms, in rock deposits dated at 3.4 billion years old. There are additional fossils recording the existence of living beings 3 billion years ago.
The state of Earth when abiogenesis occurred
The Earth is estimated to be 4.5 billion years old, once with harsh environmental conditions. Temperatures soared and volcanic activity was extreme. In addition, the atmosphere had a different composition in comparison to its composition today.
In the 1920s, Oparin and Haldane proposed an idea about the abiotic origin of life. Both of these scientists individually suggested that after Earth was created, a gradual synthesis of carbon molecules began. They thought that this became more complicated with the addition of solar radiation and heat. Then these molecules underwent an isolation process, which resulted in the creation of droplets able to isolate compounds within them. The Oparin-Haldane hypothesis claims that these droplets were the first cells subject to Darwinian evolution.
The likelihood of abiogenesis
There is always the question of whether abiogenesis is a credible view of the evolution of life. The concept of abiogenesis both on Earth and in the observable universe is highly unlikely, with the odds of its occurrence thought to be ‘less than 1 successful event expected in > 105120 events’. In fact, the ‘Borel’s Law’ mathematically shows that abiogenesis is impossible. Therefore, there are still a plethora of questions surrounding the origin of life, questions that are unlikely to be answered in the near future.