Since Antiquity, the origin of the Earth and of the living beings that inhabit it has been a matter that impresses and worries men. Several researchers believe that the Earth appeared 4.6 billion years ago and that it was formed from particles of dust and gases. They also believe that the Earth's surface was a hostile environment, with no chance for any living organism to appear. As time passed, conditions on Earth improved a lot, making it possible for life to emerge on our planet.
But, after all, how did life on our planet come about?
In the past, everyone believed in spontaneous generation theory, also known as abiogenesis theory, who argued that living beings arose from raw matter. Many scientists carried out experiments trying to prove this theory and there was even a “recipe” to produce living beings.
Just as there were scientists who defended the theory of abiogenesis, there were also scientists who doubted this theory, one of them was the Italian physician Francesco Redi, which through experiments proved that life arose from a preexisting organism. However, it was in the nineteenth century that the theory of abiogenesis was buried for good with two very important advances, the experiments of the French scientist Louis Pasteur and the evolutionary theory of Charles Darwin, which admitted a common ancestry for all living beings.
With the fall of the abiogenesis theory, the biogenesis theory gained strength and the following question was raised: If living beings arose from others, how did the first living being appear on Earth?
Three hypotheses about the origin of life were proposed:
→ Origin by divine creation (creationism): the oldest of hypotheses. Its advocates believe that a divine being created every species of life on the planet.
→ Extraterrestrial origin: also called panspermia. its defenders believe that life on Earth arose from elements or beings from other planets.
→ Origin by chemical evolution: talso known aschemical evolution theoryor theory of molecular evolution. It is the most accepted hypothesis in the scientific community.
