The pattern of evolution. General patterns of evolution

The main laws of the evolutionary process include divergence, convergence and parallelism.

Darwin still formulated the principle of signs of signs.

The discrepancy of the signs in related forms is called divergence. In the process of divergence from one source population, a whole range of forms originates, forming the branches of one tree. In an infinite row of generations, some branches die away, others develop. The forms that are most divergent in their environmental requirements have more chances to survive in the course of natural selection, as they are less competing among themselves than the source or intermediate groups. As a result of the divergence, subspecies are formed, and then species.

In evolution, another phenomenon is observed - the convergence of the process of independent acquisition by unrelated groups of organisms of similar signs. For example, body shape in fish and dolphins. This similarity is due to the overall habitat (sea) and lifestyle.

In addition to the divergence and convergence, in nature there is a parallelism - in which there is an independent acquisition of similar damn related organisms. In this case, we are talking about the generality of origin and adaptations to the same habitat. For example, sea cat, walrus, seal. The observed differences have developed at the beginning of the process of speciation.

What are the general features of the evolutionary process? First of all, this is the emergence of "feasibility" of organisms, i.e. Their compliance of habitat and their ability to change as these conditions change. Secondly, this is a process of speciation. Thirdly, the constant complication of life from primitive feeding forms to man.

In the entire history of the existence of life on Earth, about 500 million species lived. Today they are numbered about 2 million. This shows that the perfection of modern forms is the result.

evolution, in the course of which hundreds of millions of species died. Evolutionary transformations are irreversible, any simplification or deviation in the organization leads ultimately to regress and extinction.

In a threat of destruction as a result of human activity, it is important to understand the mechanisms of interaction between themselves as soon as possible and their reactions to the changes we are created, for this is the only way to avoid irreversible environmental changes.

Summing up can be said about the rules of evolution. Their three.

The rule of irreversibility of evolution. Evolution - the process is irreversible. A group of organisms cannot return to the previous state that has already implemented in a number of their ancestors. So in the evolution of vertebrates at some stage from primitive amphibians, reptiles arose, they will never give the start of amphibians. Returning to habitat in the ocean, reptiles (ichthyosaurs) and mammals (whales) did not become fish.

Even the inverse mutation, according to a specific sign, leading to the re-occurrence of this gene does not lead to the repetition of the total genotype as a whole.

The rule of progressive specialization. The group that joined the path of specialization, as a rule, will continue to follow the path of increasingly deep adaptation to narrow conditions of existence. If in the process of evolution, one of the vertebral groups acquired adaptation to the flight, then at the subsequent stage of evolution, this direction remains and enhanced. The body of a certain structure cannot live in any environment. In the choice of the adaptive zone or its part, the group is limited by the features of its structure.

The rule of alternation of the main directions of evolution. When considering the main directions in the evolution of groups of aromorphosis and idioadaptations, a regular alternation of these types of development in evolution was emphasized.

Thus, evolution is a continuous process of occurrence and developing new adaptations. Some of the newly emerging adaptations are very private, and their value is not beyond the scope of narrow conditions. Others make it possible to enter the group to a new environment and certainly lead to a more rapid evolutionary development of groups in the new direction, to a higher organization.

In addition, there are five basic patterns of evolution recognized by almost all scientists:

1. Evolution occurs at different speeds in different periods. Currently, it flows quickly, which is expressed in the emergence of many new forms and extinct many old.

2. The evolution of organisms of various types occurs at different speeds. In one pole there are plechenogues: some kinds did not change them at least for the last 500 million years - the sinks of the fossils, found in ancient rocks, are completely identical to the sinks of modern species. Another pole occupies a person: over the past few hundred thousand years, several types of hominid appeared and extinct. In general, evolution proceeds faster at the first appearance of a new species, and then, as the group stabilized, it is gradually slowed down.

3. New species are not formed from the most highly developed and specialized forms, but, on the contrary, from relatively simple, non-specialized forms. For example, mammals occurred not from large specialized dinosaurs, but from the group of relatively small non-specialized reptiles.

5. Evolution affects populations, not separate individuals and occurs as a result of mutation, differential reproduction processes, natural selection and drift of genes.

The evolutionary form of groups of living organisms is divided into divergence, convergence, parallelism.

1. Divergence - the discrepancy between the signs within the species, which leads to the formation of new groupings of individuals. The more living organisms in the structure, the method of existence, the more they differ in more diverse spaces. Usually one area or plot occupy animals with the same need for quality and food stock. After a certain time, when the food supply ends, the animals are forced to change habitat, move to new places. If animals are inhabited on one territory with a different need for environmental conditions, the competition between them weakens. So, Ch. Darwin determined that in nature at a plot of 1 m2, up to 20 species of plants belonging to 18 genera and 8 families. In the process of divergence from the progressive population, the branches of the tree of several forms would diverge. For example, you can call seven types of deer, formed as a result of divergence: spotted deer, maral, reindeer, elk, roe, Lan, Kabarga (Fig. 37).

Fig. 37. Diversity of species of deer, resulting from divergence: 1 - spot deer; 2 - maral; 3 - Lan; 4 - northern deer; 5 - elk; 6 "- Koslya; 7 - Kabarga

Under the influence of natural selection in an infinite row of generations, one forms survive, others die away. The extinction and divergence processes are closely related to each other. The most divergent on the signs of form has great opportunities to leave prolific offspring and survive in the process of natural selection, as they are less competing among themselves than intermediate, which are gradually thinned and dying.

As a result of the divergence, the population of one species is divided into subspecies. The subspecies formed under the action of natural selection, in the signs of hereditary change turns into appearance.

2. Convergence- acquisition of similar signs from different, non-standard groups. For example, at shark (class of fish), ichthyozavrov (class of reptiles), dolphins (mammalian class) body shapes are similar. This is due to the fact that they have the same habitat (water) and living conditions. Chameleon and climbing Agama belonging to different suburbs, externally similar. The similarity of various systematic groups is due to life in a similar habitat. In the organisms living in the air, there are wings. Wings of birds and bats - modified forefinder, and butterfly wings - body grown. The convergence phenomenon is widespread in the animal world.

3. Parallelism (Greek. Parallelos - "Near Going") - the evolutionary development of genetically close groups, which consists in the independent acquisition of such a similar feature of the structure on the basis of the features inherited from common ancestors. The parallelism is widespread among various groups of organisms in the process of their historical development (phylogenesis).

For example, adaptation to a water lifestyle in the evolution of lastonods developed in three directions. Catto-shaped and lastonous (walruses, eared and real seals) as a result of the transition to a water lifestyle, independently of each other, has an adaptation to water - flippers. The transformation of the front wings in many groups of winged insects in the pulp, the development of signs of amphibians, the emergence of signs of mammals in animals, etc. The similarities in parallelism indicates the unity of origin of organisms and the presence of similar existence conditions.

Evolution is an irreversible process. Each body adapted to new conditions, the altered body disappears. Returning in the former habitat, the disappeared body is not restored. Even Ch. Darwin wrote about the irreversibility of evolution: "If even the habitat is completely repeated, the appearance can never return to the previous state." For example, dolphins, whales never become fish. When transition of terrestrial animals into the aqueous medium, the limbs change the convergently - while the convergence participates only in the change in the external structure of the organs.

In the inner structure of the fins of Dolphin, China stored signs of the five-pall of the mammalian limb. Since the mutation leads to the update of the population gene pool, it never repeats the past generation gene pool. So, at some stage, reptiles arose from primitive amphibians, the reptiles cannot again give rise to amphibians.

On the stem of the evergreen shrub - the needlers have shiny thick leaves. In fact, these are modified branches. Real scratching leaves are located in the central part of these modified stems. Flowers appear early in the sinus sides of the scales, of which the fruits are later developing.

The needle leaves have disappeared in antiquity, in the process of adaptation to drought. Then during the transition again in the aquatic environment instead of the leaves, they appeared branches, similar to the leaves.

Heterogeneity of evolution. Within a few hundred million years on Earth exist unchanged sablehvost, Cystic fish, Gatteria. They are called "live fossils." However, some plants and animals change quickly. For example, in the Philippines and in Australia for 800 thousand years, several new births of rodents appeared. Approximately 20 million years on Baikal emerged 240 types of cancers belonging to 34 new births. The rate of evolution is not determined by astronomical time. The occurrence of a new species is determined by the necessary number of generations and fitness.

The rate of evolution is reduced and slowed down in the same sustainable environment environments (deep-water oceans, cave water). On the islands where little predators, natural selection is very slow. On the contrary, where intensive selection passes, evolution also flows faster. For example, in the 1930s of the XX century. Act of pests used a poisonous drug (DDT). After a few years, the form-resistant forms appeared that quickly spread on Earth. Widespread use of antibiotics - penicillin, streptomycin, gramicidine - in the 40-50s of the XX century. led to the emergence of stable forms of microorganisms.

Divergence. Convergence. Parallelism. Irreversible process. "Live fossils."

1.Volving forms of groups of living organisms: divergence, convergence, parallelism.

2. Evolution is an irreversible process, i.e., the disappeared form or body can never return to the previous state.

3. Evolution imaging change.

1. Find on the example of the divergence process.

2. Replicate convergence, disassemble it on the example.

1. Employ the irreversibility of evolution on the examples of plants.

2. What is the reason for the disappearance of some forms purchased during the divergence?

1. To see the example of the heterogeneity of evolution.

2. Disable divergence, convergence, parallelism using a circuit or table.

Basic laws of evolution

Evolution proceeds uneven, i.e. at different speeds in different periods of the history of the Earth, but tends to accelerate.

For example, the first living beings appeared about 3.8 billion years ago, multicellular - 1.3 billion years ago, mammals and poultry - 200 million years ago, Primates - 60 - 65 million years ago, Rod man - about 4 million years ago Man is reasonable - about 80 thousand years ago.

The evolution of various groups occurs at different speeds. It is customary to assess the speed of the speciation among generations. Thus, the rapid formation of new species associated with large chromosomal restructuring takes up to several tens of thousands of generations. The slow accumulation of adaptations gives a new form in a few hundred thousand generations.

Evolution does not always go from simple to complex, There is also a direction that is accompanied by the simplification of the structure. An example of such a path can serve as a common degeneration.

Small mobility and passive type of food of bivalve mollusks led to the disappearance of the head.

Evolution is an irreversible process (The rule of irreversibility of evolution), therefore, the organisms cannot return to the previous state.

The ihhthyosaution returned to the water did not become fish, but retained the features of the reptile structure.

In some organisms, including a person, in ontogenesis, as a result of a developmental impairment, the emergence of individual features that existed in the ancestors were lost in the process of evolution. These signs are called atavisms .

Atavism (Lat. atavus - The remote ancestor) - the appearance of signs in the organisms that were absent from their nearest ancestors, but existed in very distant ancestors. An example of atavism can be the development of a tail-like appendage in humans; The appearance of a horse of two extra fingers on the sides of the developed third finger.

In the process of developing individuals, the features of the organization of ancestors are repeated to some extent, the disorders of normal development may lead to the fact that the adult body will continue for the whole life signs of ancestors appearing from the embryo and usually disappearing during further development.

An example of such atavism is the appearance of a cervical fistula, resembling a gill gap ancestors of mammals - fish and amphibians. This also includes polymatism in humans (the formation of more than normal, the number of pairs of chest glasses), the three-sufficiency of horses, etc.

Atavisms also include the emergence of signs of remote ancestors in the regeneration of organs. In this case, the latter are recreated with signs characteristic of more ancient forms. For example, when regenerating the tail of the lizards of the ring, its scales are sometimes formed in a more primitive form.

Rule of progressive specialization- This is a phenomenon, as a result of which a group of living organisms, evolving along the path of adaptation to specific conditions, will continue to move along the path of deepening specialization.

The genetic bases of this rule are concluded in the process of natural selection under conditions of this adaptive zone from the population, those genes that do not correspond to it.

An example is the adaptation of gibbons adapted to the woody lifestyle. They have no grabbing tail available at other wood monkeys, so they move, jumping from the branch branch with the help of extended forelimbs. The thumb with them is significantly reduced and the hand is practically incapable of manipulation of small objects. When moving on the ground, the hands of gibbons are no longer involved in locomotion.

An example of progressive specialization serve morphological transformations of limbs in the evolutionary branch of the horses.

When moving to life on open spaces with dense soil, the number of fingers gradually decreased in the horse's ancestors until one left. This line of structure does not allow modern horses to populate other biotopes.

Principle of integration - Combining individual structures into a holistic organism. Integration is an expedient association and coordination of the actions of different parts of the holistic living system. It is manifested in combining organs into functionally unified systems, providing one of the parties to the body's life.

The four-dimensional mammalian heart is an example of an integrated structure: each of its department performs a specific function that does not mean in the separation from the functions of other departments.

Principle of Differentiation It is a separation of a homogeneous structure for separable parts, acquiring a specific structure. Thus, the complication of the structure is always associated with the complication of functions and specialization of individual parts.

An example of phylogenetic differentiation may be the evolution of the circulatory system in the type of chord.

Rudiment (Lat. rudimentum - Concept, first-pool), or vestigial organs - Comparatively simplified, underdeveloped structures, lost their main value in the body in the process of phylogenesis.Rudiment are laid during germ development, but do not fully develop.

Examples of rudiments serve: Small bertovoy bone in birds, eyes in some cave and mooring animals, the remains of the hair cover and pelvic bones in a number of cetaceans.

A person has tailed vertebrae, hair cover, ear muscles, appendix. Unlike atavisms, rudimia is found in all individuals of the species.

In this way, biological evolution (Lat. evolutio. - "Deployment") is a process of permanent and naturally directed changes to the forms of organisms on Earth, providing their fitness to environmental conditions. Such a fitness is achieved by selecting from a variety of random changes of such, which facilitate the survival of organisms in specific conditions of the medium.

Regularities of evolution

Names of laws	Semantic value patterns	Causes and explanations of patterns
Irreversible (L. Dollo 1893)	Return to the initial The state is impossible	Evolving population, integer genes are selected
Progressive complication of life forms	Total direction of evolution	Divergence and extinction of many branches while maintaining one, giving rise to a new group
Evolution - a non-promirmed process	There is no purposefulness	Direction, speed and move Nature development are set and are carried out by natural selection
Evolutionary evolution	Different pace of evolution of different groups of organisms	Stabilizing selection retains "Live minerals", driving - forms new Adaptation from populations and species
Acceleration of the pace of evolution	Each next era in the development of the earth is shorter than the previous	From prokaryotes to the first multicellular - 2.5 billion years. The first terrestrial organisms are 400 million years. Development of mammals and birds - for 100 million years. The development of a person is reasonable - 60 thousand years.

Synthetic theory of evolution. In development synthetic theory of evolution Many scientists have contributed. The term "synthetic evolution" occurred from the name of the Book of the English Evolutionist J. Huxley "Evolution: Modern Synthesis", released in 1942.

The main provisions of the synthetic theory of evolution

The material for evolution is hereditary changes - mutations (usually gene) and their combinations.
The main driving factor in evolution is natural selection.
The unit of evolution is the population.
Evolution is in most cases a divergent nature, that is, one taxon can become a certainty of several subsidiaries.
Evolution is gradual and long. The speciation as the stage of the evolutionary process is a sequential change of one time population by a series of subsequent time populations.
The view consists of subspecies and populations.
The view exists like a holistic education.
Macroevolution goes through microevolution. For the evolution of groups of species of living organisms, the same prerequisites and driving forces are characterized as for microevolution.
Any taxon usually has monofiletic origins.
Evolution has an unireded character, i.e. does not go towards any ultimate goal.

Evolution is the historical process of developing wildlife, which depends on the interaction of many external and internal factors when the selection role.

Objectives lesson:

To form knowledge of knowledge about the types of evolutionary changes.
Consider on specific examples of the path of evolution of the organic world and the relationship between them.
To familiarize yourself with the main directions of the evolution of the organic world - biological progress and biological regress.
To show the role of Russian scientists in the development of evolutionary teaching.
To form the skills for determining aromorphosis and idioadaptations in the plant and animal world.

Equipment:tutorial on biology "Homologous and similar organs of plants and animals", presentation to the lesson.

DURING THE CLASSES

I. Actualization of reference knowledge

- What is biological evolution? (B. Evolution is an irreversible development of the organic world).
- What is the evolutionary process called microevolution? (The process of education of new species).
- What is the macroevolution? (The process of formation of larger systematic units - childbirth, families, etc.).

II. New Material

1. Types of evolutionary change (lecture, conversation).

(In the course of viewing slides, students write definitions in the notebook).

The main types of evolutionary changes include parallelism, convergence and divergence ( Attachment 1 , Slide 2).

Parallelism is an independent acquisition of similar signs related organisms living in the same conditions and leading a similar lifestyle.
For example, the structure of the body of mammals inhabiting the rain forests of Africa and South America has a common similarity ( Attachment 1 , Slide 3).

Convergence - The occurrence of similar features of the structure in unrelated organisms living in the same conditions and leading a similar lifestyle.
For example, four animal groups were given to large aquatic predators: mollusks, reptiles, birds, mammals.
What common features of the structure can be allocated in these animals belonging to various systematic groups ( Attachment 1 , Slide 4)? (Fins, streamlined body shape).
Convergent evolution addresses only the external structure of organisms, which is associated with the conditions of habitat. The wing of birds and butterflies are a device for flight, but the origin and structure of these organs is different. Organs are different by origin, but carrying out similar functions are called similar ( Attachment 1 , slide 5)

Divergence - the discrepancy of the signs in the population's tails, the species arising under the influence of natural selection, leading to the emergence of new species, detachments, classes, etc.

As a result of the divergent evolution, the mammalian class broke up on numerous detachments, whose representatives differ in structure, lifestyle, the nature of physiological and behavioral adaptations ( Attachment 1 , Slide 6).
- What caused the formation of numerous groups of mammals? (Adaptation to various environmental conditions)
Modified whale fines, birds, bats, crotes, rats - the result of a divergent evolution. These organs have the same common structure of the structure, but perform various functions. Such organs are called homologous ( Attachment 1 , Slide 7).

2. Ways and directions of the evolution of the organic world

In the development of the problem of evolution, large Russian scientists A.N. Severstev and I.I. Shmalhausen. They found that the main paths of evolution are aromorphosis, idioadaptation, degeneration ( Attachment 1 , Slide 8).

Contribution of Russian scientists in the development of evolutionary teaching (brief reports of students)

A.N. Severstetsev is a famous zoologist and the largest theorist of evolutionary teaching. The creator of the domestic school of evolutionary morphologists. Organized and headed the laboratory of evolutionary morphology and animal ecology. The creator of the generally accepted theory of origin of the five-pall of limb and pair fins in animals. The author of the theory of phylumbriogenesis, according to which new signs may appear at any stage of ontogenesis, and the morphobiological theory of evolution paths, in which the four main directions of biological progress set: aromorphosis, idioadaptation, centrogen, general degeneration.
I.I.Shmalgausen graduated from Kiev University in 1907. Student A.N.Severtsev. Moscow University has headed the department of Darwinism organized by him. Twelve years led the Institute of Evolutionary Morphology of the USSR Academy of Sciences. Its numerous works are devoted to comparative anatomy and embryology, evolutionary morphology, origin of terrestrial vertebrates, paths and patterns of evolution, biocybernetics. Its studies of the mechanisms of the evolutionary process and individual development as the author-repeated systems anticipate a number of Cybernetics provisions, from the position of which he in 1950-60. Outlined an evolutionary theory. His scientific legacy had and continues to have a great influence on the development of biological science.
(Benp, "Cyril and Melodies", 2003)

Aromorphosis - Adaptive changes in total value, increasing the level of organization and the viability of individuals, populations, species.
The first terrestrial vertebral animals began the beginning of a group of cyzer fish, thanks to the change in the structure of the skeleton of paired fins. As a result, five-plated limbs were formed, capable of maintaining the body over the ground ( Attachment 1 , Slide 9).
An example of aromorphosis in plants is the appearance of a flower (modified escape) in coated plants.
Idioadaptation - private adaptive changes, useful in this habitat arising without changing the overall level of the organization.
An example of idioadapation in animals can serve as a variety of beaks of Hawaiian flowers that feed on the nectar of various coated plants.
The adaptation to the spread of seeds by the wind is an example of one of the ideoadaptations in plants ( Attachment 1 , Slide 10)

Evolution path ratio

Ondatra is the North American type-in-edge, the distribution area of \u200b\u200bwhich is constantly expanding. As a result, he begins to force out local species with similar environmental needs, for example, exhaust and water vole.
Biological regression ( Attachment 1 , Slide 14) is characterized by:

Decrease in the number of individuals.
Narrowing the number of range.
Reducing the number of species, populations.

The cause of biological regression can be a change in environmental conditions, to which the species could not adapt or competition from other species. So it was with the numerous reptile dominant on Earth, to shift which, thanks to warm-bloodedness, birds and mammals came.
Currently, changing the environment, uncompressed species in new conditions of existence, the person will be the cause of biological progress or regression. Attachment 1 , slide 21)

V. Homework: §63, Notebook.

Was used:

1. Educational electronic edition "Ecology", Moscow State Institute of Electronics and Mathematics, 2004.
2. 1C: School, Ecology, 10-11 cl., Edited by A.K. Aklebinin, V.I. Syivagovz
3. Laboratory practice. Biology 6-11 CL. Republican Multimedia Center, 2004.
4. BENP, BIOLOGY 6-11 CL., Ministry of Education of the Russian Federation, GURTS EMTO "Cyril and Myifodius", 2003.
5. D.K. Belyaev, A.O. Ruvinsky General biology for 10-11kl., Moscow, "Enlightenment", 1991.
6. A.A. Kamensky, E.A. Kriksunov, V.V. Beekeeper, General biology, 10-11kl. Drop, Moscow, 2005.
7. General biology lessons: Teacher / V.M. Korsunskaya, G.N. Mironenko, Z.A. Mokeeva, N.M. Verlyin - M: Education, 1986.

Among the researchers, there are no discrepancies in ideas about specific molecular mechanisms underlying mutations that are important for evolution, on the degree of impact on the evolution of individual organisms of factors such as natural selection, isolation, genetic recombination, hybridization and magnitude of a multiplying population. However, for some major moments managed to achieve agreement. It is quite clear that the primary material for evolution is the changes in genes and chromosomes, which is necessary for the origin of a new species, one or another isolation is necessary and that natural selection ensures the preservation of some, but not all arising mutations. In addition, there are five basic patterns of evolution recognized by almost all scientists:

Evolution occurs at different speeds in different periods. Currently, it flows quickly, which is expressed in the emergence of many new forms and extinct many old.

The evolution of organisms of various types occurs at different speeds. In one pole there are plechenogues: some kinds did not change them at least for the last 500 million years - the sinks of the fossils, found in ancient rocks, are completely identical to the sinks of modern species. Another pole occupies a person: over the past few hundred thousand years, several types of hominid appeared and extinct. In general, evolution flows quickly at the first appearance of a new species, and then, as the group stabilized, it gradually slows down.

New species are not formed from the highest and specialized forms, but, on the contrary, from relatively simple, non-specialized forms. For example, mammals occurred not from large specialized dinosaurs, but from the group of relatively small non-specialized reptiles.

Evolution affects populations, not individual individuals and occurs as a result of mutation, differential reproduction processes, natural selection and drift of genes.

The interaction of the environment and object can be represented in the following form

Picture 1.

Here the arrow A shows the effect of the medium on the object being studied, and the arrow B expresses the action of the object to the external environment. Taking advantage of the convenient terminology of the theory of communication, let's call and the channel in which the environment affects the system studied. Then the effect of the system (object) on Wednesday is implemented on the channel B.

But an example from biology. A living organism always functions in a particular environment. It can be a forest, a desert, water, a flask, etc. on the channel and the body comes food and all external stimuli, and on the channel b, the body affects the environment, changes its position in this medium, etc.

A similar representation is not to leisure the clarification and has a deep meaning. It establishes a strict relationship between objects in the world and, in fact, allocates and determines the significant causes of communication. Moreover, since any system is inherent individual properties that characterize the relationship between its entrance A and the y outlet, then, observing A and B, you can know this object.