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Role in the evolution of biological progress. Progress and regress. Criteria for biological progress and regression Biological progress includes

Biological progress is carried out in various ways.

The first method consists in the improvement in the historical process of the most important organ system for the life of organisms. Therefore, it is called morphophysiological progress. In the second method, the system of organs that are secondary to the life of organisms changes, and therefore their structure does not become more complicated, but they adapt to the environment. In the third way, organisms undergo biological progress as a result of a change in their organization from simple to complex.

Under aromorphosis, i.e., morphophysiological progress, understand evolutionary changes that cause a general rise in the degree of organization, an increase in the intensity of the vital activity of organisms. Aromorphoses give living beings significant advantages in the struggle for existence and open up opportunities for the development of new habitats.

Examples of adaptations resulting from the progressive direction of evolution include:

  • the emergence of multicellular;
  • transition to sexual reproduction;
  • chord formation;
  • the formation of the spinal column;
  • the appearance of five-fingered limbs;
  • fin formation;
  • the formation of a three-chambered heart in amphibians;
  • the formation of two circles of blood circulation in amphibians;
  • development of warm-bloodedness;
  • complication of the brain;
  • transition to internal fertilization in vertebrates;
  • transition at

Biological progress is the main, main lines of evolution. Biological progress characterizes individual groups of organisms at certain stages in the development of the organic world.

Criteria for biological progress:

1. An increase in the number of individuals of the group under consideration.

2. Expansion of the range.

3. Intensive form and speciation.

As a result, it is observed entering a new adaptive zone with subsequent adaptive radiation, that is, distribution in various habitats.

In the event that the rate of evolution of a given group of organisms lags behind the rate of environmental changes, the stabilization phase is replaced by the phase biological regression. The criteria for regression are exactly the opposite of the criteria for progress. In the future, the transformation of a group of organisms into a relic or their extinction is possible. Regression is often associated with narrow specialization and degenerative phenomena. Currently, regression is facilitated by environmental change under the influence of anthropogenic factors - so fast that populations do not have time to change their genetic structure.

It must be emphasized that biological regression is not a fatal inevitability: there are no biological laws that limit the time of existence of taxa.

The main way to achieve biological progress is arogenesis , or morphophysiological progress – the process of increasing the overall level of organization .

Criteria of arogenesis (morphophysiological progress):

a) systemic– improvement of systems of homeostasis and homeoresis; (homeostasis - stability of the state, for example, constant body temperature, constancy of salt composition, constancy of the content of O 2 and CO 2, constancy of pH ...); (homeoresis - sustainability of development, for example, the ability to form a certain phenotype in changing environmental conditions);

b) energy– increase in efficiency. organism (compare pollination in pine and in flowering plants); in a particular case - an increase in the level of metabolism (birds, mammals);

in) informational- an increase in the amount of information: genetic (increase in the amount of DNA in the cell) and epigenetic (memory, learning).

A. N. Severtsov was the first to separate the concepts of biological and morphophysiological progress (the latter means the complication of organization). Biological progress, in contrast to morphophysiological progress, can be achieved not only by increasing the level of organization (aromorphosis) and particular adaptations (idioadaptation), but also by secondary simplification of organization - general degeneration, which is one of the forms of specialization. Tapeworms can serve as an example of a biologically progressive taxon, the evolution of which followed the path of general degeneration.

Sections: Biology

Goals:

  • to form students' knowledge about the main ways and directions of the evolutionary process;
  • to form the ability to correctly compare different directions and paths of evolution, to illustrate the story about them with various examples from the world of plants and animals;
  • to systematize and generalize knowledge about the process and main results of the historical development of the organic world.

Tasks:

  • using examples to show the origin of large systematic groups by aromorphosis;
  • consider examples of idioadaptation, degeneration and the relationship between the main paths of evolution;
  • to acquaint with the main directions of evolution - biological progress and biological regression;
  • characterize the role of man in biological progress and regression of species.

LESSON STRUCTURE:

I. Learning new material

The idea of ​​a directional nature of evolution, following the path of progress, that is, along the path of improving organisms from simple to complex, from lower forms of life to higher ones, is generally accepted. However, one should not think that progress is the only path of evolutionary change, in fact it is only one of the possible directions.

Modern ideas about the directions of evolution are based on the works of Ivan Ivanovich Shmalgauzen and Alexei Nikolaevich Severtsov. AN Severtsov singled out the concepts of biological progress, biological stabilization and biological regression.

1. Biological progress

Biological progress is characterized by an increase in the number of individuals of a systematic group, an increase in the number of species, subspecies, populations included in it, and an expansion of the range. Species that are in a state of biological progress emerge victorious in the struggle for existence.

Biological progress is characteristic of angiosperms, insects, birds and mammals.

In accordance with the various transformations in the structure of organisms in the process of evolution, there are three ways to achieve biological progress:

  • Aromorphoses - arogenesis(morphophysiological progress);
  • Idioadaptation - allogenesis;
  • General degeneration - catagenesis(morphophysiological regression).

Arogenesis- an evolutionary direction, accompanied by the acquisition of major structural changes - aromorphoses.
Aromorphosis means the complication of organization. Taking it to a higher level. Changes in the structure of animals as a result of the occurrence of aromorphoses are not adaptations to any environmental conditions, but make it possible to expand the use of environmental conditions (new food sources, habitats). An example of aromorphosis in mammals is the division of the heart into left and right halves with the development of two circles of blood circulation. The differentiation of the digestive organs, the complication of the dental system, the appearance of warm-bloodedness reduces the dependence of the body on the environment.

Aromorphoses played an important role in the evolution of all classes of animals: the tracheal respiratory system and the transformation of the oral apparatus in insects, the formation of a chitinous cover and the dismemberment of limbs, the development of a complex NS, as well as the sense organs - smell, sight, touch. The appearance of speech is a major aromorphosis in human evolution. In the plant world, large aromorphoses are the appearance of organs and tissues, photosynthesis, the appearance of flowers, fruits, and seed reproduction in angiosperms.

Further evolution of angiosperms followed the path idioadaptations, that is, along the path of the emergence of various adaptations to various living conditions.
Idioadaptation led to the emergence of plants with various flowers, fruits, shoots, leaves, root systems, development periods, adaptations for pollination by wind, water, and insects.
Idioadaptation is a path of evolution in which some adaptations are replaced by others that are biologically equivalent to them.
Idioadaptations, unlike aromorphoses, are of a private nature.
A good example of idioadaptation is protective coloration in animals, various adaptations for cross-pollination by wind and insects, adaptations of fruits and seeds for distribution, adaptation to the bottom lifestyle (flattening of the body) in many fish.

2. Biological stabilization

According to A.N. Severtsov, biological stabilization means maintaining the body's fitness at a certain level. The body changes according to changes in environmental conditions. Its numbers are not increasing, but they are not decreasing either.
In plants, with a decrease in the average annual temperature, the number of covering hairs of the epidermis increases. This phenomenon allows all individuals to survive, but there is no advantage between other species, since they show the same reaction.

3. Biological regression

biological regression- the direction of evolution, which is characterized by a decrease in the number of species, subspecies and populations, a decrease in the number of individuals and range.
Biological regression means a decrease in the fitness of an organism.
The organism lags behind changes in the external environment, and especially from the pace of evolution and distribution of ecologically close forms.
The number of the species is decreasing and the species is heading towards extinction. Biological regression can also affect biologically highly organized forms that flourished in their time, which turned out to be not adapted to new or changing living conditions (extinct dinosaurs, mammoths).

Cause of biological regression often a human activity. Man influences species directly, destroying them, or indirectly, changing their habitat. So, at the beginning of the 17th century, wild bulls tours (the progenitors of modern bulls) were exterminated. In the second half of the 18th century, the marine mammals of Steller's cows were completely destroyed. By the beginning of the 19th century, hunters had completely exterminated the large flightless moa birds in New Zealand, whose growth reached three meters.
The end result of regression is the extinction of the species.

Laboratory work

Topic: "Aromorphoses in vertebrates"

Target: to form the ability to identify aromorphoses in animals, to explain their meaning.

Working process:

1. Consider the diagrams of the structure of hearts and remember the features of the circulatory system of representatives of the class of vertebrates: fish, amphibians, reptiles, birds, mammals.

Fill the table:

2. Remember what the intensity of metabolism and the ability to maintain a constant body temperature, which depends on it, is characteristic of representatives of the classes of vertebrates.

Fill the table:

3. Consider the diagrams of the structure of the respiratory systems and remember the features of the breathing of representatives of the class of vertebrates.

Fill the table:

4. Recall the features of fertilization and development of offspring in representatives of classes of vertebrates.
Fill the table:

5. Analyze the tables. Make a conclusion: what large aromorphoses contributed to the appearance of amphibians, reptiles, birds, mammals. Expand the evolutionary significance of aromorphoses.

II. Lesson conclusions:

  • The doctrine of the directions of evolution was developed by A.N. Severtsov and I.I. Shmalgauzen;
  • Directions of evolution - biological progress and biological regression;
  • Biological progress is achieved through aromorphosis, idioadaptation and degeneration;
  • The causes of regeneration can be human activities.

Homework:§ 52; complete lab work

Literature:

  1. Handbook of a biology teacher. Authors-compilers: Kalinova G.S. Kuchmenko V.S. Moscow - AST Astrel, 2003.
  2. Sivoglazov V.I., Sukhova T.S., Kozlova T.A."General Biology". Lesson plans 11th grade. A guide for the teacher. M.Iris-Press, 2004.
  3. Cyril and Methodius Virtual School General Biology Grade 11, 2007.

biological progress reflects the course of the evolutionary process, leading to the success and prosperity of some group of organisms. The main signs of biological progress include:

an increase in the number of individuals in this group,

range expansion,

the emergence of numerous closely related taxa.

biological regression is the opposite process. Regression is the simplification or depression of a group of organisms. Biological regression is a decrease in the level of adaptability to living conditions, as evidenced by:

decrease in the number of individuals,

reduction in the range of the species,

a decrease in the number and diversity of its populations, varieties, species.

Group evolution rules.

    According to the rule of irreversibility of evolution, evolution is an irreversible process, and organisms cannot return to the previous state already passed by their ancestors earlier.

    Progressive specialization rule argues that the phylogenetic group, evolving along the path of adaptation to given specific conditions, will continue to move along the path of deepening specialization. An example of progressive specialization is the morphological transformation of limbs in the evolutionary branch of horses. During the transition to life in open spaces with dense soil, the number of fingers in the ancestors of the horse decreases to one, which does not allow modern horses to inhabit other biotopes.

    rule of origin of new groups of organisms from unspecialized ancestors. There are many examples illustrating this rule. Indeed, mammals evolved from reptiles that retained some of the features of amphibians in their organization.

15. Individual and historical development. Law of germinal similarity formulated by the Russian scientist K.M. Baer.

Law: in the early stages, the embryos of all vertebrates are similar to each other, more developed forms go through the stages of development of more primitive forms. Only in later phases do signs of a class appear, then an order, a family, a genus, a species, and an individual.

Comparing the ontogenesis of crustaceans with the morphology of their extinct ancestors, F. Müller concluded that living crustaceans in their development repeat the path traveled by their ancestors. Based on these observations, as well as studying the development of chordates, E. Haeckel formulated the main biogenetic law, according to which each individual in its individual development (ontogeny) repeats the history of the development of its species (phylogenesis), i.e. ontogeny is a brief and rapid repetition of phylogenesis. Recapitulation- repetition of structures characteristic of ancestors in the embryogenesis of descendants. Recapitulate not only morphological characters - notochord, anlage of gill slits and gill arches in all chordates, but also features of biochemical organization and physiology. However, in the ontogeny of highly organized organisms, a strict repetition of the stages of historical development is not always observed, as follows from the biogenetic law. Thus, the human embryo never repeats the adult stages of fish, amphibians, reptiles and mammals, but is similar in a number of features only to their embryos.

Biological progress is the only direction of evolution that led to the appearance of man. This direction causes the transition in the process of evolution to the social level.

As is known, the ways of achieving biological progress, the course of historical development (phylogeny) for each particular taxon (group) depends on the adaptive zone in which, in fact, this taxon evolves. Equally important are the possibilities of restructuring in the organizational structure of the group.

Touching upon the main problem that biological progress solves, scientists pay attention to the role of each existing factor in determining one or another direction in development. In other words, the study of this very issue allows us to see how fitness can increase and evolution as a whole can occur.

The first to study this direction was J. B. Lamarck. The scientist divided biological progress into two types. To the first he attributed gradation - raising the organizational level. The second of them, according to the scientist, is the formation of a variety of types of organization at each specific level. The scientist believed that these two processes are independent of each other. Thus, gradation is due to an internal desire for improvement, while diversity is formed under the influence of the environment. At the same time, it should be said that, despite the fact that J. B. Lamarck misinterpreted the mechanism of two directions, their very existence is an objective fact.

Darwin saw biological progress differently. He equalized and fixtures. As a result, according to Ch. Darwin, the increase in the organizational level was only a partial result of this whole process. As a rule, with the complication of organization in the process of evolution, an increase in fitness is combined. In the process of divergence of features (divergence), the biotic environment becomes constantly more complex. Darwin further suggested that adaptation to a more complex environment could only be achieved through a more complex structure of the organism. Subsequently, biological progress was studied in two directions. Research was carried out in Russia by A. Severtsov and abroad by J. Huxley and B. Rensh.

Like J. B. Lamarck, B. Rensch believed that it was possible not only vertically, but also horizontally. The formation of diversity at one level of organization was called cladogenesis by Rensch, while the emergence to a new level was called anagenesis. In turn, J. Huxley returned to the definition of "city" (steps), proposed by J. B. Lamarck. At the same time, the scientist also identified a third direction in which biological progress occurs, calling it stasigenesis. He considered this direction a phenomenon of stabilization, the preservation of persistent, unchanging branches. Analyzing all directions, J. Huxley came to the question of where evolutionary development can lead in general and what can become a criterion for its progressiveness. As a result, J. Huxley's paradox arose: who is more progressive - the tubercle bacillus that provokes a person's disease, or the person himself?

The scientist tried to solve the emerging issues in his theory of unlimited and limited development. According to this theory, evolution is, of course, biological progress. However, this development is group, and therefore limited. Passing from one stage to another, each taxon (group) progresses, but, at the same time, comes to extinction, that is, to stasigenesis. At the same time, only one direction of development, which led to the emergence of man, is unlimited. This is mainly due to the exit to a completely new evolutionary level - the social one.