Theory of biogenesis: explaining the appearance of life

Life itself hides many secrets that escape human compression. One of the greatest mysteries is the origin of all life, an idea which has been around the thoughts of mankind and which has always been tempting to our curiosity. Therefore, several attempts have been made to explain this step, either by faith or by science.

Many theories have emerged throughout history to attempt to explain the origin of life, such as the theory of biogenesis. This model indicates that life can only be generated from a pre-existing life. Very easy to understand: a hen is born from the eggs of another hen. This is not a much more mysterious explanation, but its importance lies in the fact that it emphasizes the subject of the origin of life, since at the time of its appearance, the idea of ​​spontaneous generation predominated.

    In the beginning: the theory of spontaneous generation

    The truth that one cannot speak of biogenesis without first evoking the model which has supplanted the scientific and popular panorama. The spontaneous generation proposed that life can be generated from inert matter. This idea came from the observation that after the putrefaction of an organic sample, insects and microorganisms appear which did not exist before.

    It was a great success for the theory of biogenesis to disprove a pattern rooted in world design for many years. The idea of ​​spontaneous generation is dated to its origin in ancient Greece, in the hands of Aristotle; the philosopher argued that some life forms could appear without further delay from inert matter. For example, worms came out of heated mud or flies from rotten meat.

    These beliefs proposed by Aristotle have survived for many centuries without anyone questioning them. It wasn’t until the 17th century that someone wanted to deny the idea. was and the Italian naturalist Francesco Redi.

    Redi’s experience

    This researcher designed an experiment to show that insects do not reproduce spontaneously. To do this, he put eight types of meat in eight glass jars, leaving four of them completely uncovered, while the other half covered them with gauze, which allowed air to pass but not insects. .

    After a few days, the meats that were discovered exhibited larvae, while those covered were apparently not harboring life. The result of the experiment showed that flies must lay their eggs in the flesh for other of their species to appear. It is an experiment which is linked to the theory of biogenesis and which would have succeeded in ousting spontaneous generation without the discoveries of the Dutchman Anton Van Leeuwenhoek, the father of microbiology.

    Leeuwenhoek, a few years after the Italian conducted his research, repeated Redi’s experiment, but this time examined the meats under a microscope. In the uncovered and covered meats, microorganisms could be observed, a result which has kept the ideas of spontaneous generation as feasible at least for these living organisms.

    Pasteur’s experience

    The theory of spontaneous generation lasted a few centuries longer, although there were earlier attempts to refute it, such as those of the priest Lazzaro Spallanzani, who showed that if you carefully close a container with broth and heat, no microorganisms develop; but supporters of orthodoxy at the time attributed this to the fact that he had killed his whole life by heating it.

    It was not until 1861, when the French chemist Louis Pasteur unequivocally proven that these beliefs were false, showing evidence in favor of the theory of biogenesis. The experiment he proposed consisted of filling long-necked S-shaped flasks. This silhouette lets in air but not microorganisms, because they are retained in the curve. Then the filling was heated the flask to remove any microorganisms that were already present in the solution.

    The result was that the solution remained unchanged for weeks, but if it broke the neck of the balloon, then within days the sample became contaminated. This showed that the microorganisms growing in the inert material were in fact attracted to the air, and not that they will be generated spontaneously.

      The theory of biogenesis and its relevance

      As I progressed, the theory of biogenesis has little mystery, although it is easy to see in the case of animal births, it has not been so easy to understand in other fields, as in the case of putrefaction.

      However, the theory of biogenesis does not explain the origin of life, because it has no way of indicating what the first living organism was. That is why there are other theories about the origin, many of them are abiogenesis, that is, the origin of life was inorganic matter, but only the beginning. There are even theories of exogenesis, according to which life came from outside the planet Earth. In any case, the origin of life remains a mystery.

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