The elementary unit of the evolutionary process is ...

It is difficult to imagine that once our planetlooked completely different. Everything was different: plants, animals, atmosphere, water. For many millions of years the Earth has undergone changes that led to its present state of affairs. These changes are of a periodic nature and have their scientific name - evolution. Let's try to understand what it is and how its processes proceeded.

The concept of evolution

If we define in terms ofbiological science, then we can say so. Evolution is irreversible changes in time occurring in living organisms and leading to the consolidation at the genetic level of newly acquired characteristics that allow them to adapt to any environmental conditions.

In this case, the unit of the evolutionary process isnot every specific individual, because there are whole groups consisting of identical organisms. Therefore, the idea of ​​the elementary link of this large-scale process was for a long time ambiguous. Modern scientists unanimously declare that the unit of the evolutionary process is the population.

The process of any person can be traced toa concrete example from nature, if given such a goal. Thus, the appearance of adaptations for an appropriate way of life in moles is very evident, coupled with a complete loss of sight. After all, there is no light under the earth, therefore vision is not important. But the sense of smell of these creatures can be envied. Feel the smell of earthworm for a few tens of meters!

It is obvious that the ancestral forms of theseanimals led a terrestrial way of life and were neither deprived of sight nor of the forelimbs of a normal structure. Of course, this transformation did not happen immediately. Many centuries, millennia, and even millions of years were needed for Mother Nature to bring moles to the kind in which they are known to us now. And so with all organisms. It should not be thought that we live in a stationary world where the biomass is completely stable and formed.

Evolution continues even now, exposing changes in all animals, plants, microorganisms, even humans. It just happens on a genetic level, and can not be seen by contemporaries.

Terminology of Evolutionary Learning

There are a number of notions thatlearn how to operate in order to have an idea of ​​the evolution and processes accompanying it. With the passage of time, the accumulation of a base of theoretical knowledge and the generalization of all material received, the terms that denoted certain organisms and changes in their states, actions, and phenomena of nature also arose. Many metamorphoses and processes pertain to evolution, but we will define them as the main ones.

1. Heredity is the ability of organisms to transmit to their offspring the characteristics fixed in the genotype. Thanks to it, there are identical individuals that form whole populations.
2. Variability is such a feature in organisms that appears from birth and persists throughout life, which allows you to acquire new features by combining the genotypes of the father and mother.
3. Mutations are an important part of the phenomenon under consideration. The unit of the evolutionary process is, of course, not a mutation. However, this is the driving force behind the changes in time.
4. The struggle for existence is naturalrivalry of individuals for territory, food, an advantageous place to live, water, a female and so on. It is this struggle that determines the number of animals and plants, their strength and endurance. Those that survive become stronger and leave, respectively, a more enduring and adapted offspring.
5. Natural selection is a process performed by nature itself, determining in life the place of each individual, limiting their number, limiting the progression in reproduction and survival.
6. The unit of the evolutionary process is the population. It is a group of similar organisms, transmitting a certain set of characteristics to the offspring and having the same set of morphological, physiological and anatomical features, determines the smallest structural unit of the development process.

To fully understand the phenomenon under consideration, it is also necessary to clearly understand such ecological concepts as species, genus, population, biocenosis, biomass, biosphere and others.

History of development of evolutionary doctrine

The concept of evolution as a development process has cometo people not at once. Initially, the changes in plants and animals were mentioned in ancient times. Then sages, philosophers and researchers noticed that with the passage of time individuals change, many have similar signs. Among the most famous minds were:

• Thales.
• Xenophanes.
• Heraclitus.
• Alkmeon.
• Empedocles.
• Plato.
• Aristotle.
• Hippocrates and others.

The Middle Ages and Modern Times

In the Middle Ages the most commonthe theory of the origin and development of life was Creocementist. God was considered the only creator who created the Earth as it is, and any other views were not considered possible. This slowed down the development of true ideas for a long time.

Later, when the era of geographicaldiscoveries and became aware of the enormous diversity of life on Earth, it was time for a theoretical explanation of this diversity. Then the theory of evolutionary transformations appeared. Her father is rightly considered the world-famous Englishman Charles Darwin. However, along with him, almost the same discovery was made by another scientist - Alfred Wallace. In place of Creo-Zionist views came the transformational.

Their essence consisted in the belief that the Earth wasand only in the course of time many transformations have taken place and those organisms that exist now have been formed. In addition, the process of transformation has not stopped, but continues to this day and will continue always as long as life exists.

The doctrine of Darwin evolution

What does the theory created by an Englishman say? What is the unit of the evolutionary process and why does it happen at all? Let's designate some key positions of the given doctrine.

1. All the diversity of life that exists on the planet is the result of millennial transformations, and was not created overnight by one Creator.
2. Evolution is based on such processes as natural selection, hereditary transmission of information to generations, mutations that arise in populations, variability of species.
3. New signs arise and are consolidated as a result of the struggle for existence, which is a means of natural selection.
4. The result of evolution is the formation of an organism that is maximally adapted to the conditions of its existence.

Charles Darwin gave not only theoreticalan explanation of the development of life, but also reinforced all this with ongoing experiments. The only thing he could not understand and explain was the discreteness of inherited characteristics. According to his views, those signs that passed down from generation to generation had to be transformed and faded over time. However, the experiments of Mendel proved that they arise several generations later.

Unit of evolutionary process for Darwin

In order to explain any process, it follows thatselect its elementary cell. So with evolution. Charles Darwin believed that the species is a unit of the evolutionary process. Is this true today? No, because, from the point of view of the current synthetic theory of the development of life, the species can not be considered as the smallest particle of the global change in time.

According to the views of contemporaries, the elementary unit of the evolutionary process is the population. The reasons will be considered later.

Darwin believed that the smallest cell is a species. He described and recorded those changes that occurred within a single species of individuals, considered the entire set of factors that affect these changes.

What is a view?

Why can not we assume that the unit of evolutionaryprocess is the view? Because we have already indicated that the outcome of the development of life is adaptation to local factors. Acquisition and consolidation of those signs that will help to freely exist in certain areas.

However, let's remember, for example, the polar edge. The place where snowstorms always sweep and dazzle the white snow, where cold and cold make you tremble. In these parts there is not one specific species of animals, but their adaptation to such harsh conditions are extremely similar. It is thick fur with undercoat, white color, thick layer of subcutaneous fat, large sizes and so on.

Thus, it turns out that species are different, andsigns of adjustment similar. That is why the unit of the evolutionary process is not a species, it is simply an elementary cell of ecology as a science. This is a collection of individuals with similar morphological, physiological characteristics, lifestyle, as well as occupying a certain area and freely interbreeding, forming fertile offspring.

Population as an elementary unit of the evolutionary process

The modern theory of evolution is synthetic. It is the result of the merger of all the views of Charles Darwin, of contemporary research and reasoning. She does not have a definite author, she is a product of the work of many scientists from different countries.

So, it is this theory that determines the unit of the evolutionary process is the population. It is the smallest unit cell of this global process of transformation.

From the ecological point of view, the population is a formthe existence of certain types of organisms, in which they are best adapted to environmental conditions. One population can include both individuals of one kind and different species. The symptoms that they possess may also differ. Some organisms can be small, others large and so on.

In each population there is a struggle for existence, natural selection, mutations are formed and certain features are fixed. And this is exactly what evolution is.

The driving forces of evolution

We have already mentioned the basic processes that are the engines of this macro-evolution - evolution. Let us denote them again.

1. Natural selection, carried out due to the struggle for existence within the population and between them.
2. Heredity and variability, leading to the fixing of important new signs in the genotype.
3. Mutations are both beneficial and harmful. Random or directed, they lead to the consolidation of new signs.
4. Artificial selection - directed evolution, carried out by a person to obtain the necessary species of animals and plants (this is done by plant breeding and animal husbandry).

The significance of heredity in the process of evolution

The ability to transmit characteristics by inheritance -this is an important feature of all living beings. It provides an opportunity to reproduce identical individuals, but at the same time to receive new ones. Heredity is the basis of life.

Its biological role is to maintain the numbers of individuals of different species and preserve them in nature. In addition, it is one of the main directing forces of evolution.

Variability and its role

It can not be said that variability is a unitevolutionary process. Is it such an important part of it? Of course. It is in this process that the basis for acquiring new features and features lies. The ability of the organism to recombine, form new attributes and fix them - all this is due to variability.