Home > Abiogenesis
Abiogenesis, in its most general sense, is the hypothetical generation of life from non-living matter. Today, the term is primarily used in the context of biology and the origin of life.Some confusion exists on this topic, because early concepts of abiogenesis were later proven to be incorrect. These early concepts of spontaneous generation (referred to here as "Aristotelian abiogenesis" for clarity) held that living organisms could be "born" out of decaying organic substances, et cetera, which we now know does not occur.
- "Abiogenesis is the field of science dedicated to studying how life might have arisen for the first time on the primordial young Earth. Despite the enormous progress that has been made since the Miller-Urey experiment, abiogenesis is under constant attack from creationists, who continually claim that the origin of life by random natural processes is so unlikely as to be, for all practical purposes, impossible." [1]
1 History of abiogenesis hypotheses
Aristotelian abiogenesis, also known as spontaneous generation, (and, in older texts, Generatio aequivoca, Generatio primaria, archegenesis, autogenesis, and archebiosis), was the theory according to which fully formed living organisms sometimes arise from not-living matter. Aristotle explicitly taught this form of abiogenesis, and laid it down as an observed fact that some animals spring from putrid matter, that plant lice arise from the dew which falls on plants, that fleas are developed from putrid matter, that mice come from dirty hay, and so forth. Alexander Ross, in commenting on Sir Thomas Browne's doubt as to "whether mice may be bred by putrefaction", gives a clear statement of the common opinion on abiogenesis held until about two centuries ago. Ross wrote:
- "So may he (Sir Thomas Browne) doubt whether in cheese and timber worms are generated; or if beetles and wasps in cows' dung; or if butterflies, locusts, grasshoppers, shell-fish, snails, eels, and such like, be procreated of putrefied matter, which is apt to receive the form of that creature to which it is by formative power disposed. To question this is to question reason, sense and experience. If he doubts of this let him go to Egypt, and there he will find the fields swarming with mice, begot of the mud of Nylus, to the great calamity of the inhabitants."
The first step in the scientific refutation of the theory of Aristotelian abiogenesis was taken by the ItalianThe Italian Republic or Italy ( Italian: Italia is a country in the south of Europe, consisting mainly of a boot-shaped peninsula together with two large islands in the Mediterranean Sea: Sicily and Sardinia. To the north, where it borders France, Switzer Francesco RediFrancesco Redi ( February 18/ 19, 1626 March 1, 1697) was a physician born in Arezzo, Italy. He is most well-known for his experiment in 1668 which is regarded as a one of the first steps in refuting abiogenesis. At the time, prevailing wisdom was that ma, who, in 1668Events January The Triple Alliance of 1668 is formed. February 13 Lisbon Peace Treaty between Afonso VI of Portugal and Carlos II of Spain, by mediation of Charles II of England where it is recognized the legitimity of the portuguese monarch. Portugal yie, proved that no maggots were bred in meat on which flies were prevented by wire screens from laying their eggs. From the 17th century16th century 17th century 18th century more centuries) As a means of recording the passage of time, the 17th century was that century which lasted from 1601- 1700. During this period, the power of England and the United Provinces increased; while that of onwards it was gradually shown that, at least in the case of all the higher and readily visible organisms, abiogenesis did not occur, but that omne vivum ex ovoOmne vivum ex ovo is Latin for "All live [is] from [an] egg". This is a foundational concept of modern biology. Up into the 19th century it was commonly believed that life forms can appear spontaneosly under certain conditions; for example, that maggots w, every living thing came from a pre-existing living thing.
The discovery of the microscope carried the refutation further. In 1683Events June 6 The Ashmolean Museum opens as the world's first university museum. June 12 The Rye House Plot to assassinate Charles II of England is discovered September 7 Polish-German troops arrive in Vienna to help the besieged November 1 The British cr Antoni van Leeuwenhoek discovered bacteria, and it was soon found that however carefully organic matter might be protected by screens, or by being placed in stoppered receptacles, putrefaction set in, and was invariably accompanied by the appearance of myriads of bacteria and other low organisms. As knowledge of microscopic forms of life increased, so the apparent possibilities of abiogenesis increased, and it became a tempting hypothesis that whilst the higher forms of life arose only by generation from their kind, there was a perpetual abiogenetic fount by which the first steps in the evolution of living organisms continued to arise, under suitable conditions, from inorganic matter. This was mostly disproved by Lazzaro SpallanzaniLazzaro Spallanzani ( January 10, 1729 February 12, 1799) was an Italian biologist. He was born in Modena and died in Pavia, Italy. Spallanzani was educated at the Jesuit College of Reggio, and started to study law at the University of Bologna, which he g, who, in 1768, proved that microbes came from the air, and could be killed by boiling. His work paved the way for Louis Pasteur.
It was due chiefly to Louis Pasteur that the occurrence of abiogenesis in the microscopic world was disproved as much as its occurrence in the macroscopic world. If organic matter were first sterilized and then prevented from contamination from without, putrefaction did not occur, and the matter remained free from microbes. The nature of sterilization, and the difficulties in securing it, as well as the extreme delicacy of the manipulations necessary, made it possible for a very long time to be doubtful as to the application of the phrase omne vivum e vivo to the microscopic world, and there still remain a few belated supporters of abiogenesis. Subjection to the temperature of boiling water for, say, half an hour seemed an efficient mode of sterilization, until it was discovered that the spores of bacteria are so involved in heat-resisting membranes, that only prolonged exposure to dry, baking heat can be recognized as an efficient process of sterilization. Moreover, the presence of bacteria, or their spores, is so universal that only extreme precautions guard against a re-infection of the sterilized material. It was thus concluded definitely that all known living organisms arise only from pre-existing living organisms.
