Topic - 25. Evolution of ontogeny

The evolution of ontogeny. Evolutionary changes are associated not only with the formation and extinction of species transformation bodies, but also to the restructuring of ontogenetic development. The ontogeny - the development of an individual since the formation of the zygote or other natural bud before completion of its life cycle (until death or termination of existence in the same capacity). Ontogeny - one of the basic phenomena of life on our planet. Ontogeny - the deployment process, the implementation of the hereditary information stored in the germ cells. Without the occurrence of ontogenetic evolution of life J would have been unthinkable, or would have stopped at the stage of "primitive and immortal" mucus homogeneous bunch.

Phylogeny is inconceivable without change of individuals in ontogeny, phylogeny because, figuratively speaking, a chain or thread genetically-linked to each other by ontogeneses - individual development cycles. Ontogeny - not just the result of phylogeny, but its prerequisite. All this determines the critical importance of studying the problem of correlation onto- and phylogenesis for understanding the evolutionary theory.

Features ontogeny in different groups. Forms of expression of individuality in nature diverse disparity in content and process of ontogenesis in various representatives of prokaryotes, fungi, plants and animals.

In plants, ontogeny is more labile due to insufficient development of the regulatory system (see. Below). The ontogeny of plants in general more dependent on environmental conditions than animals.

Variety of ontogeny in different groups of organisms (even the representatives of one type) indicates a specific role of environmental factors in the stabilization differentsirovok and life cycles. Although the selection is on holistic ontogeny, individual stages act as necessary prerequisites for the realization of the program and the flow of information between generations.

Integrity and stability of ontogenesis. Individual always develops as a whole. Structural and functional integrity of the individual is based on the relationship and interaction of ontogenetic differentiation.

Species in ontogeny - no mosaic parts and organs, and specifically reacts whole (II Schmalhausen). Any blastomere at Ile-Closed due to other blastomeres developed as part of the whole natural selection undoubtedly contributes to the development of phenotypes with more holistic ontogeny - increasingly interdependent stages of development. In: whole evolution of life accompanied by a gradual increase in the differentiation and integrity of ontogenesis (II Schmalhausen). In this regard, one can speak not only to strengthen the integrity, but also to increase the stability of ontogeny in the evolution of life.

Embrionizatsiya ontogeny. Embrionizatsiya ontogeny - is the emergence in the evolution of the ability to undergo stages of development under the protection of the mother's body or special (seed or egg) shells. As already indicated, embryonic development - is not the original property of living, and the result of evolution.

Neoteny. Encountered during evolyutsii ability to reproduce the early (larval) stages of ontogeny is called neoteny. For neotenic forms characteristic premature ripening (Axel transceiver). Individuals reach sexual maturity at the same time retain the juvenile form.

Fetalizatsiya - method of evolutionary changes of organisms characterized by a slowdown in the ontogenesis of individual organs or systems, and the resulting persistence in the adult organism embryonic state of the corresponding attributes. For example, the preservation of fetal skeletal tissue (cartilage) in the skeleton of amphibians, cartilaginous fish and cyclostomes, the predominance of the cranium over maxillary department in the human head.

Autonomization - the main direction of the evolution of ontogeny. In the evolution of ontogeny is the emergence of various mechanisms and improving the sustainability of ontogenetic development in general. There is a gradual reduction of the determining role of physico-chemical environmental factors in individual development.

Result ontogeny autonomy manifested in the comparison of different species of animals and plants in the same conditions. Thus, in an incubator under the same conditions of the different species of birds eggs develop chicks with features characteristic of the species. Autonomization ontogeny detected in maintaining the ability of normal development in warm-blooded animals poi wide temperature fluctuations.

Ontogeny -the basis of phylogeny. The question of when changes occur in the ontogeny affecting phylogeny, - one of the classic in evolutionary theory. Ontogeny - the basis of phylogeny for the reason that it is the individual ontogeny (individual) - the object of the action of natural selection. Evolutionary changes that accumulate small species adaptation consist essentially in a steady change in the course of ontogenesis of individuals (usually called filembriogenezami). Filembriogenez - evolutionary change course of ontogenesis.

Evolutionary changes in ontogenezis may occur in the early, middle and late stages of development. Among them distinguish changes arhallaksisov type (from the Greek. Arche - beginning, allaxis - change), the deviation (from pozdnelat. Deviatio - deviation) and anaboly (from the Greek. Anabole - lifting).

Anabol -shaping evolutionary change in the later stages of development. Such changes are common in ontogeny and lead to a lengthening of the development of any organ or structure. With each new anaboly previous final stages of development as it moved into the interior of ontogenesis. For example, changes in the structure of the skeleton of vertebrate muscle differentiation in the distribution of blood vessels associated with supers at later stages of development.

Deviation -evolutionary evasion in developing organ in the middle stages of its formation. An example is the development of a deviation from cheshui squaloid and reptiles. Bookmark scales, those and other begins with local compaction of the lower layer of the epidermis and the accumulation of connective tissue beneath it in the form of the papilla. Do squaloid papilla grows in the middle stages of embryogenesis forms tooth scales.

Arhallaksis -evolutionary change in the initial stages of the fore-moobrazovatelnyh processes or changes themselves the rudiments of organs. Thus there is a radical restructuring in the development of organ rejection in the development of the ancestors and descendants from the beginning. For example, increasing the number of vertebrae in snakes, fin rays in some species of fish, the number of teeth of the toothed whales - the result of changes in the number of primordia in the early stages of development.

The doctrine of recapitulation. Ontogeny - not only predposylka phylogenetic development, but its result. For this reason, the study of the ways in modern evolutionary process of animals and plants is possible by analyzing the characteristics of their embryonic development.

Changes in the phylogeny of the group occur only through a transformation-formations in ontogeny. Usually these changes relate to the individual development of the later stages of development.

The notion of progress and its criteria. Progress - it's the best, not just a new. However, transfer characteristics of an evolutionarily "advanced" forms a hard time, because they are different in different groups.

Relativity -the main characteristic of progressive change. Darwin saw progress as inevitable phenomenon in the evolution of nature, connected with usovershenstvovaniem and gradually "increase organizations' most of the living beings. At the same time, he emphasized that natural selection does not necessarily imply improvement of the organization and the simultaneous existence of a "low-and-you sokoorganizovannyh" exists, does not contradict the theory of natural selection.

The essence of biotechnical progress, like any other form of progress is to occur under the influence of natural adaptation-tion selection.

2. Парамонов А. А. Дарвинизм. М. «Просвещение», 1999

3. Яблоков А. В. Юсуфов А. Г. Эволюционное учение М., «Высшая школа», 2004

5.Иорданский Н.Н.Основы теории эволюции. М,.1998

6.Варонцов Н.Н. Сухорукова Л.Н. Эволюция органического мира М.,1991

Human evolution. Despite the fact that the problem (anthropogenes - the emergence of man - from a purely zoological point of view are private phylogenetic question, traditionally included in the presentation of the foundations of evolutionary theory. The reason for that, on the one hand - great methodological significance of the materialist solution to the question of the origin of man, and with other - an opportunity to see how the laws of organic evolution, acting at the level of biological form of motion of matter, giving way to another, related to the emergence of the social form of motion of matter.

Similarities and pour into the structure of the human body and animals. Man, though is the owner of consciousness, high intelligence, the creator of the major cities, skyscrapers, jet planes, giant icebreakers and other wonders, has a number of similarities with the higher animals in the structure of his body.

Rudimentary organs and atavism in humans. In humans, there are vestigial organs. One of them - the appendix of the cecum (the appendix), 2-3 cm long. In all animals that eat roughage, well developed cecum and appendix. There food undigested in the stomach, finally digested.

In mammals, animal ears are very mobile, as provided with special muscles, resulting in their movement. In humans, these muscles and ears are rudimentary.

The man sometimes observed phenomena of atavism. Examples of this are the cases of children born with a tail or thick hairy pokrovom, extra nipples.

The similarity in the embryo development of man and animals. Humans and other multicellular animals their individual development begins with the fertilized egg - the zygote.

Similarities and differences in the structure of the human body and the great apes. According to the structure of the body and features of the physiological properties of all wildlife apes Nai closer to the man. In the structure of the skeleton and internal organs of apes and humans there are very many similarities. In the skeleton as apes and humans accrued 12-13 pairs of ribs, 5-6 sacral vertebrae.

Differences in the structure of the human body and the great apes. The volume of the human brain is about 1400-1650 cm3 and apes - 600 cm3. The surface of the cerebral cortex of the human brain in the middle of 1250 cm3, and apes, it is less than about 3.5 times. Apes are not capable of abstract thought, as they have underdeveloped cerebral cortex, especially its frontal, temporal, and other departments. Each species of apes featured on one is closer to the man, and on the other is farther away.

Drivers anthropogenes. The question naturally arises, what it consists of the driving factors (forces) of human origins - anthropogenes? Darwin showed that the main factors of organic evolution - genetic variation, struggle for existence and natural selection - may be applicable also to the evolution of man.

Biological factors, although of great importance in the origin of man, but they are clearly not sufficient to explain anthropogenes. In this process, along with biological played an important role as well and social factors.

Monkeys are not immediately passed to the upright posture. Environmental change - the transition from their forests to life on the open places - has led some apes to the emergence of mutation - the ability to walk upright, which over millions of years, improved and maintained as a result of the struggle for existence and natural selection.

So, in the formation of man from apes importance imeli transition to upright posture, hands-free, making tools, social life, the use of a mixed meal, the use of fire and the development of the second signal system.

1. Константинов А. В. Основы теории эволюции М., «Высшая школа», 2000

2. Парамонов А. А. Дарвинизм. М. «Просвещение», 1999

3. Яблоков А. В. Юсуфов А. Г. Эволюционное учение М., «Высшая школа», 2004

4.Банина Н.Н. Закономерности прогрессивной эволюции. П., 1998 г.

9. Билич ГЛ., Крыжановский В.А. Биология полный курс. Ботаника 2т.М., 2005 г.

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