Abiogenesis is what?

The centuries-old history of mankind knows many hypotheses about the origin of life on Earth. From the most ancient centuries in this matter there are two absolutely opposite points of view. One of them argues that the living is born from the non-living is abiogenesis. The second is of the opinion that the living can only arise from the living - this is biogenesis. What is the difference between the theories of biogenesis and abiogenesis, let's try to understand this article.

History of views

Representations about the origin of life are clearly correlated with the level of knowledge of a particular era. In ancient times, when the level of knowledge was still small, the theories of the origin of the living striking with its fantastic. Here are some views of philosophers and naturalists of the past. For example, Empedocles (5th century BC) believed that trees carry eggs. Aristotle (4th century BC) claimed that lice come from meat, and bugs are from the juice of the body of animals. These views of the spontaneous generation of life as such existed until the middle of the XVII century, when the English philosopher F. Bacon (1561-1626) theoretically, and the Italian physician F. Redi (1626-1698) and Louis Pasteur (1822-1895) practically proved the impossibility of spontaneous generation of life . It was then that these two opposing camps began to form, two mutually exclusive theories of the origin of life-biogenesis and abiogenesis.

A bit of theory

Under abiogenesis (from the Greek prefix of denial - a, bio - life and genesis - occurrence) understand the theory of the emergence of organic structures from inorganic and outside living organisms. In a broad sense, abiogenesis is a theory about the origin of the living from the lifeless. And here it is necessary to clarify what to regard as life and when the inanimate becomes alive. And since today the definition of life is treated differently and from different points of view, there are many supporters of both abiogenesis and biogenesis.

Life in the theory of abiogenesis

In this concept, the most important are the genetic and evolutionary criteria that determine life. All other criteria - thermodynamic and ecological - are recognized as secondary. The hypotheses of the abiogenesis hypothesis are as follows:

• The living and inanimate differ in chemical composition and its characteristics (metabolism). All the theories of this direction are called biochemical abiogenesis.
• The origin of life occurred precisely on Earth, in a natural way and with the costs of free energy. This is the result of the appearance of complex organic substances from simple inorganic ones with the advent of new chemical reactions between them. All the theories of the origin of life in this direction are called geocentric.
• The main properties and signs of the living are metabolism, self-reproduction of oneself, heredity and variability.

Thus, abiogenesis is geocentric and chemical theories that explain the origin of the living.

Life as a result of biogenesis

Biogenesis is at the forefront of thermodynamic and ecological properties that distinguish living from nonliving. In this case, genetic, evolutionary and biochemical approaches are considered additional. The concepts of biogenesis are as follows:

• The living, like the inanimate, are two interrelated and inseparable states of matter. These theories are called physical.
• The thermodynamic (confrontation of entropy) and the systemic (subordination and stable dynamic links) component are the main properties and signs of life.
• Life originated in the universe, and the Earth's biosphere is a manifestation of the living part of the Cosmos. These theories call cosmic.

Biogenesis, therefore, is a cosmocentric physical theory of the origin of life.

Modern views

Modern science holds a point of view that unites all concepts into a single system of knowledge about how non-living matter has evolved into a living one. As the most probable way of living origin, modern science recognizes that the initial stage is abiogenesis. And it consists of 3 initial stages:

• The appearance of biological monomers.
• Formation of biological polymers.
• The appearance of membrane structures and primary protozoa, protobionts.

Further development of life on earth was already easier - according to the evolutionary mechanisms of Charles Darwin (heredity, variability and selection).

Non-biological education of organics

Chemical evolution or prebiological abiogenesis is the emergence of organic substances from inorganic substances. In 1924 the Russian academician A.I. Oparin (1894-1980) suggested that in areas saturated with high-molecular compounds solutions spontaneously formed zones of increased concentrations (coacervates or coacervate drops), which are isolated from the environment but maintain exchange with it. The theory of Oparin in 1929 was supported by the English scientist John Haldane (1892-1964), and the theory of coacervates firmly established in science, which presupposes the spontaneous generation of organic substances at the early stages of the development of our planet with unique physical conditions.

Proofs of the hypothesis of abiogenesis

At first, it was not possible to prove the possibility of spontaneous synthesis of organic substances from inorganic substances. However, certain milestones have already been passed and results obtained.

And it all began in 1953, when chemists Stanley Miller and Harold K. Urey conducted an experiment with the primary broth (a medium similar to the prebiotic on Earth). The influx of energy (up to 60 thousand V) under pressure and at a temperature of 80 degrees Celsius led to the formation of fatty acids, urea and several amino acids (protein monomers). And already in 2008, American biologists created a "protocell" with a membrane, in 2011 Japanese biologists published works on the creation of a vesicle with a membrane and the ability to divide.

Slackness of positions

Despite the successes of biologists in experimental attempts to confirm the theory of Oparin-Haldane about the origin of life on the planet in coacervates, all the resulting structures are far from the structure of a living cell. The world community does not recognize these experiments as an indisputable proof of just such a birth of life. Both biogenesis and abiogenesis are theories that have not been confirmed experimentally for today. Given that the path from inorganic molecules to a living cell has been long, with a lot of forks and stops, the scientist still has to guess how this path could be traversed. But all these hypotheses do not prove that everything just happened on Earth many billion years ago.

The probability is absolutely incredible

The randomness of the appearance of a living cell in the primary broth is calculated mathematically. The British mathematician Fred Hall, using modern computers, calculated the probability of accidental formation of an amoeba protein. And this probability was negligible - 1/10 * 40,000. Recall that this is under some ideal conditions. And this leads to certain reflections and gives arguments to supporters of other theories and concepts of the origin of life on our planet.

Incredible Probably

But, as you know, everything is relative. On our planet and in our world - this is an indisputable fact. Here are a few examples that will make you wonder - is it so impossible for such an accident, as the emergence of life in the primary broth.

• If the life expectancy of a person were 100,000 years, then we are guaranteed (that is, 100%) to die in air crashes.
• The probability of winning the Cool Million lottery is 1 to 5 200 000. Nevertheless, American Valerie Wilson won the main prize twice: in 2002 and in 2006.
• In 2009, in the Bulgarian lottery "6 out of 41" in two copies with a difference of 4 days, the same figures fell out (4 15 23 24 35 42). The probability of such an event is 3.61 • 10 ^-14 .