One of the topics on which humanity has philosophized and debated for many years is the origin of life; The hypotheses that have been developed around this theme have been diverse, acquiring mystical, divine and/or extraterrestrial overtones to the synergy of various events that led to the first forms of life that eventually gave rise to each of the organisms over time. as we know them today.
Among the explanations that generated the most controversies, is the hypothesis of abiogenesis or spontaneous generation, which indicated that life came from organic or inorganic matter or a combination of both, that is, that living beings could appear ‘of nothing‘ without the need for the prior intervention of others; It should be noted that this explanation was not issued after following what is now known as the scientific method, it was simply based on the visualization of various events.
Among the main supporters of this idea, was Aristotle who observed the appearance of worms, insects and even fish as a result of dew, humidity or sweat; This is where the term ‘entelequia’ arose, which was used to name the supernatural force that had the ability to give life or originate it in that which did not have it. This hypothesis remained for several centuries, until in the 19th century and thanks to the advances that had been made up to that time, it was possible to begin to question it.
John Needham, a biologist and Catholic priest, was another proponent of spontaneous generation and to test this he carried out an experiment in which he boiled nutrient broths to eliminate the possible presence of pre-existing organisms and sealed them (not completely to allow passage). air) to prove that with the passage of time the appearance of microorganisms was imminent.
On the other hand, those who finally managed to refute these ideas were Francesco Redi, Lazzaro Spallanzani and Louis Pasteur (the latter was the one who ultimately gave the final and forceful thrust).
In the first place, Redi carried out an experiment where he contemplated three containers in which he placed fresh meat; the first he left uncovered, the second he covered with gauze, and the third with parchment. After time, flies and worms appeared in the first jar, in the second the presence of larvae was observed on the gauze, but not in the meat, while in the one that was covered with parchment no type of organism was present. which deduced that living beings do not appear from inert matter.
For his part, Spallanzani replicated Needham’s experiment, except that he sealed the flasks hermetically and as a result the presence of microorganisms was not detected; Needham argued that this was due to the fact that entelechy is found in the air and by not allowing it to pass through, the microorganisms did not manifest themselves. Finally, Louis Pasteur’threw to the ground‘ the hypothesis of spontaneous generation by replicating Needham’s experiment, but modifying the structure of the flasks containing the nutrient broths, in such a way that they did allow air access, but due to their design (swan neck), the microorganisms they remained trapped in the neck of the container without being able to access the content.
This contribution from Pasteur makes it clear that for life to originate, the intervention of other living beings is necessary, but then how did the first living beings originate? What was the first; the egg or the chicken? The theories that have tried to explain it, we will be able to comment on the following Friday, however, what I intend to highlight on this occasion is that even with the advances and limitations of different times, the human being has remained in the constant search for answers; sometimes he succeeds, in others he learns and in others he leads the way so that others can hopefully finish deciphering each dilemma.