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Modern teaching about evolution

Lesson objectives: To develop knowledge about the development of the doctrine of evolution in the late 19th and early 20th centuries; To develop the ability to analyze and evaluate the contribution of various fields of biology to the creation of a synthetic theory of evolution, to characterize modern theory

Problem What achievements of biology can serve as the basis for the modern theory of evolution?

Wilhelm Ludwig Johansen coined the term “population” in 1903

A.P. Semenov-Tyan-Shansky In 1910, he defines the concept of “subspecies”

Chetverikov Sergei Sergeevich In 1926, he published an article “On some aspects of the evolutionary process from the point of view of modern genetics”, genetic data should form the basis of the doctrine of variability and become the key to understanding the process of evolution. Chetverikov proved that mutations in natural animal populations do not disappear, but can accumulate in a latent (heterozygous) state and provide material for variability and natural selection. Thus, he managed to connect Darwin's evolutionary teachings and the laws of heredity established by genetics.

Ronald Fisher John Haldane Julian Huxley Nikolai Ivanovich Vavilov Dubinin Nikolai Petrovich

Modern theory of evolution Synthetic theory, because developed thanks to Darwinism, genetics, systematics, cytology, morphology, molecular biology, biochemistry, physiology, ecology Based on the population idea

George Simpson First used the expression "synthetic theory of evolution" in a precise application to this theory in 1949.

The STE provisions consider the population to be the elementary unit of evolution; the material for evolution is mutation and recombination variability; natural selection is considered as the main reason for the development of adaptations, speciation and the origin of supraspecific taxa; genetic drift causes the formation of neutral traits; a species is a system of populations reproductively isolated from populations of other species, and each species is ecologically distinct; Speciation consists of the emergence of genetic isolating mechanisms and occurs primarily under conditions of geographic isolation.

On the topic: methodological developments, presentations and notes

Technological map for studying the topic “Fundamentals of the doctrine of evolution” (methodological development of lessons) for the course “Biology. Introduction to general biology and ecology” for 9th grade. Pasechnik line V.V.

Technological map for studying the topic “Fundamentals of the doctrine of evolution” in a biology course for 9th grade. (Methodological development of lessons). Textbook “Biology. Introduction to general biology and ecology" for 9th grade....

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Darwinism

Charles Darwin (1809-1882) Charles Darwin's father Robert Waring Darwin Charles Darwin's mother Susanna Darwin House in Shrewsbury (England) where Charles Darwin was born

Prerequisites for the emergence of the theory of Charles Darwin Discoveries in biology the cellular structure of organisms - R. Hooke, A. Leeuwenhoek the similarity of animal embryos - K. Baer discoveries in the field of comparative anatomy and paleontology - J. Cuvier Works of the geologist Charles Lyell on the evolution of the Earth's surface under the influence of natural reasons (t, wind, precipitation, etc.) Development of capitalism, agriculture, selection Creation of animal breeds and plant varieties 1831-1836 - trip around the world on the Beagle

Voyage around the world on the ship "Beagle" 1831-1836 Darwin returns from a trip around the world a convinced supporter of the views on the variability of species

The importance of artificial selection for the creation of Darwin's theory Artificial selection is the process of creating new breeds (varieties) through systematic selection and reproduction of individuals with traits valuable to humans. From the analysis of vast material on the creation of breeds and varieties, Darwin extracted the principle of artificial selection and on its basis created his evolutionary doctrine

The creative role of artificial selection: individuals selected by humans for reproduction will pass on their characteristics to their descendants (heredity); the diversity of descendants is explained by different combinations of characteristics from their parents and mutations (hereditary (indefinite according to Darwin) variability)

The creative role of artificial selection Artificial selection leads to a change in an organ or trait of interest to a person Artificial selection leads to divergence of characters: members of a breed (variety) become more and more different from the wild species Artificial selection and hereditary variability are the main driving force in the formation of breeds and varieties

Forms of artificial selection Unconscious selection is selection in which the goal is not to create a new variety or breed. People preserve the best, in their opinion, individuals and destroy (cull) the worst (more milk-producing cows, better horses). Methodical selection is a selection carried out by a person according to a specific plan, with a specific goal - creating a breed or variety

Creation of evolutionary theory 1842 - beginning of work on the book “The Origin of Species” 1858 - A. Wallace, while traveling in the Malay Archipelago, wrote an article “On the tendency of varieties to deviate unlimitedly from the original type,” which contained theoretical principles similar to Darwin's. 1858 - Charles Darwin received his article from A.R. Wallace. Alfred Wallace (1823-1913, England) Charles Darwin (1809-1882, England)

Creation of evolutionary theory 1858 – On July 1, at a special Meeting of the Linnean Society, the concepts of Charles Darwin and A. Wallace on the emergence of species through natural selection were presented. 1859 – the first edition of the book “The Origin of Species”, 1250 copies

Darwin's concept of natural selection All creatures have a certain level of individual variability Traits from parents are inherited by offspring Each type of organism is capable of unlimited reproduction (there are 3000 seeds in a poppy pod, a female elephant brings up to 6 calves in her entire life, but the offspring of 1 pair in 750 years = 19 million individuals) Lack of vital resources leads to the struggle for existence. In the struggle for existence, the individuals most adapted to given conditions survive

Darwin's concept of natural selection The material for evolution is indefinite variability Natural selection is a consequence of the struggle for existence Forms of the struggle for existence Intraspecific (between individuals of the same species) Interspecific (between individuals of different species) Fight against unfavorable conditions (t, lack of water and food, etc. .)

Driving forces of evolution according to Darwin Hereditary variability Struggle for existence Natural selection

Natural selection is the main guiding factor of evolution Adaptation that ensures the survival and reproduction of offspring Divergence is the gradual divergence of groups of individuals according to individual characteristics and the formation of new species The result of natural selection

Comparison of artificial and natural selection Questions for comparison Artificial selection Natural selection Material for selection Diversity of descendants Diversity of descendants Who selects Human Environmental conditions Who is left Individuals with traits valuable to humans The most adapted individuals Result New varieties and breeds New adaptations, new species

Zenkina Victoria Gennadievna, Ph.D., Associate Professor

Lecture outline

1. Definition of the concept “evolution”. The essence of creationism and transformism 2. The theory of evolution of J. B. Lamarck

3. Factors of evolution according to Charles Darwin

4. SSTE (modern synthetic theory of evolution)

5. The concept of macro- and microevolution

6. Biological species. Population structure of the species. Ideal Population

7. Teachings of A.N. Severtsov about morphophysiological progress - the main direction of the evolutionary process.

8.Biogenetic law and teachings of A.N. Severtsova about phylembryogenesis

9. Population structure of humanity. Demes and isolates. The influence of the mutation process, migration, isolation, genetic drift, selection on the human population

10. Genetic polymorphism. Genetic aspects of susceptibility to disease

Evolutionary doctrine

the science of the historical development of groups of organisms related by origin, i.e. evolution (from lat. deployment)

the term “evolution” was first used in biology by the Swiss naturalist and philosopher C. Bonnet in 1762

evolution is an irreversible process that occurs over time, as a result of which a something new, heterogeneous at a new stage of development

Creationism concept

The emergence of living things as a result of an act of creation, the constancy and immutability of everything that exists (C. Liney, J. Cuvier)

Heraclitus, Empedocles, Democritus and Lucretius (BC)

During the Middle Ages, the dominance of theistic views

During the Renaissance, there was an increase in interest in the natural sciences, including biology. But ideas about the lowland nature dominated

In the XV-XVIII centuries. - rapid development of production and various

areas of science, a number of discoveries that contributed to the rapid progress of evolutionary theory (the invention of the microscope - the cellular structure of all organisms, indicating the unity of their origin)

Transformism theory

transformo - transform, transform

The theory was based on the variability of living organisms during their historical existence

Transformism is a materialistic concept of evolution that rejects the idea of ​​deity

Life arose from the smallest corpuscles, as a result of the transformation of the first living beings and the emergence of more advanced organisms

R. Hooke, E. Darwin, D. Diderot, J. Buffon, E. Geoffroy Saint-Hilaire, I. Goethe, A. A. Kaverznev and

K. F. Roulier

The main provisions of Lamarck's theory:

1. Species variability- all of nature consists of a continuous series of individuals; species do not really exist, but can change. New species arise as a result of the smooth transformation of old forms

2. Graduation principle– the possibility of arranging living bodies in stages depending on the degree of complexity of their organization

Factors of evolution according to Lamarck:

The internal desire of organisms for self-improvement

Active influence of environmental factors

Lamarck's laws of evolution

I. In every animal, frequent and longer use of organs leads to their enlargement, non-use leads to reduction or disappearance

II. Everything that is acquired under the influence of external conditions, as a result of exercise, or lost due to disuse, is inherited by descendants

Thus, the key point of Lamarck's theory was the inheritance of acquired characteristics.

Lamarck correctly viewed evolution as a progressive process of increasing complexity of an organization, which has an adaptive nature

Charles Darwin's theory of evolution

“The Origin of Species by Natural Selection”:ideas about the variability of organisms

Darwin identified two main forms of variability - definite (group) and indefinite (individual)

genetic drift and founder's principleact as reasons for the formation of neutral characteristics;

a species is a system of populations reproductively isolated from populations of other species, and each species is ecologically distinct;

speciation consists in the emergence of genetic isolating mechanisms and is carried out mainly in conditions of geographic isolation

Modern (synthetic)

evolution theory

Teacher Smirnova Z. M.

Modern evolutionary teaching is a synthesis of genetics, Darwinism and other sciences,

that's why it got the name “synthetic” theory of evolution (STE).

The connection between genetics and evolution was established in 1926 by the Soviet geneticist Sergei Sergeevich Chetverikov.

He showed that the first elementary evolutionary processes begin in populations.

S. S. Chetverikov

(1880 – 1959)

Modern evolutionary teaching

In STE, the principles of Charles Darwin are taken as a basis, but significantly deepened and supplemented.

If according to Darwin the process of evolution is the evolution of individuals, then according to STE:

• the basic elementary unit of evolution is the population;

• a factor that can influence the gene pool of a population - an elementary evolutionary factor .

Modern evolutionary teaching

STE studies micro- and macroevolutionary processes

Macroevolution – evolutionary process leading to formation of supraspecific taxa (genera, orders, classes and even types).

The result of macroevolution is the gradual complication and increase in the organization of living beings.

Microevolution – evolutionary processes occurring at the population level and leading to formation of new species.

Microevolutionary process is adaptive in nature .

Microevolution.

Population is an elementary unit of evolution and species

Selection begins within the population, because its individuals have different genotypes and, consequently, different characteristics and properties.

The collection of genes in a population is called the gene pool.

According to G. Hardy and V. Weinberg, in large populations, where there are no mutations, selection and mixing with other populations, constancy of allele frequencies, homo- and heterozygotes, is observed, which is expressed by the formula:

p 2 (AA) + 2pq (Aa) +q 2 (aa) = 1

Populations that satisfy these conditions are stable and do not evolve.

Speciation

(microevolution)

All facts that cause deviations from the Hardy-Weinberg law lead to a change in allele frequencies in the population, which entails an evolutionary process.

Changes in gene frequencies in a population are an elementary evolutionary phenomenon.

Elementary factors of evolution

(processes that change the genetic composition of a population):

Population waves

Mutational

process

Insulation

Genetic drift

or (genetic-automatic processes)

Recombination of genetic material

Factors supplying

material for the action of natural selection –

the main guiding factor of evolution

Mutations as a factor of evolution

Mutation process - leads to the transition of a gene from one allelic state to another (A a)

or to a change in a gene (A C), is the direct cause of a change in the frequency of a given gene in a population.

• Most mutations are recessive;
• More than 90% of mutations reduce the survival of homozygotes or lethal;
• Some mutations increase the survival rate of homozygotes or heterozygotes under certain conditions. For example, antibiotic-resistant microorganisms (hospital strains).

Mutations as a factor of evolution.

Conclusions:

• The set of alleles resulting from mutations constitutes the original elementary evolutionary material.

• In the process of speciation it is used as the basis of the action of other elementary evolutionary factors.

• The mutation process occurs constantly throughout the entire period of life.

• Gene pools of populations experience continuous

pressure of the mutation process.

Factors of evolution - population

waves (waves of life) –

are called periodic fluctuations in the number of organisms in natural populations.

A population that has sharply decreased in size is then restored at the expense of surviving individuals, and since these separately surviving individuals cannot be the custodian of the population’s gene pool, the population that has recovered in numerical composition will have a different gene pool, as a result, the appearance of the population changes.

Factors of evolution - population waves

Common squirrel ( Sciuris vulgaris ) (solid line) and the yield of spruce seeds ( Picea excelsa ) (dotted line)

1930

1935

1940

At the bottom of the population curve, a “bottleneck effect” is observed. Few individuals pass through it, and in the new population the ratio of alleles will be different.

Factors of evolution – genetic drift –

change in the frequency of genes in populations as a result of any random reasons:

• migrations;
• natural disasters;
• waves of life.

Genetic drift leads to the fact that over a long series of generations the population becomes homozygous, this is how 100% fixation of one of the gene alleles occurs and

loss of others.

Isolation as a factor of evolution

Isolation – restriction of freedom of crossing (panmixia) of organisms

Forms of insulation

Reproductive

(biological)

Geographical

(spatial)

Ecological

Genetic

Seasonal

Ethological

Morphological

Geographical (spatial) isolation

Geographical – spatial separation of populations, leading to the impossibility or difficulty of crossing between them, due to the features of the landscape within the species’ range - the presence of water barriers for “land” organisms, land areas for aquatic species.

For example, the various species of finches that inhabit the Galapagos Islands.

Galapagos

finches

Buds/fruit

Leaves

Seeds

Insects

Larvae

Uses thorn

Reproductive

(biological) isolation –

arises due to intraspecific differences organisms and has several forms:

• Ecological – associated with the habitat of populations in different biotopes ;
• Genetic – determined by the death of zygotes after fertilization, sterility of hybrids or reduced viability;
• Seasonal - reproduce at different times;
• Morphological – different structure of copulatory organs;
• Morphological – different structure of copulatory organs.

Natural selection is the main guiding factor of evolution

Elementary factors of evolution are characterized

not direction, because they introduce random changes in the ratios of allele frequencies in populations. Those. elementary factors create the material for the action of natural selection. Selection picks up randomly occurring mutations that are useful for given environmental conditions and saturates the gene pool with them, while harmful mutations are eliminated.

This is the guiding role of selection in evolution.

Natural selection is the only creative factor of evolution that directs random hereditary changes along the path of formation of adaptations (adaptations).

Speciation is the final stage of microevolution

Speciation is the process of the emergence of new species on the basis of hereditary variability under the influence of natural selection.

In the process of speciation, the transformation of genetically open intraspecific systems (populations) occurs

into genetically closed systems (new species).

Main modes of speciation

Sympatric (ecological)

Allopatric (geographic) speciation

Allopatric (geographic) Speciation is based on spatial isolation. It occurs in cases where a new species arises from populations that find themselves territorially separated.

When species meet again in the same territory, they do not interbreed.

the formation of a new species as a result of the development by a population of a new habitat within the range of a given species or as a result of the emergence of differences in lifestyle.

Mechanisms:

• Separation of ecological niches
• Separation of ecological niches (temporal, spatial);

• Genetic
• Genetic – polyploidy (instant speciation) or interspecific hybridization in plants.

Sympatric (ecological) speciation –

Sympatric speciation is related as a result of ecological (e.g., food) specialization.

It is believed that this is how five species of tits were formed: by the choice of feeding places and by the composition of the food they eat.

Blue tit

Moskovka

Great tit

Tufted tit

Gaichka

Food: Small Butterflies, seeds Large Insects; Seeds

insects; wood plants; insects; conifers;

Place End branches of trees; Branches and trunks Bark, buds Terminals

feeding: park trees; trees; branches

Sympatric speciation –

often associated with genomic and chromosomal mutations and, as a consequence, genetic isolation. For example, many plant species arose through polyploidy based on the original forms.

Haploid Diploid

Triploid Tetraploid

Teosinte plant -

descendant of the wild ancestor of corn

Cultivated corn

The nature of the evolutionary process

Parallel development – when exposed to similar conditions closely related organisms they experience independent development of similar characteristics.

Divergence – process of divergence of characteristics in related organisms observed when conditions of existence change

Convergence – development process in a similar direction unrelated groups, living in similar environmental conditions

Analogues:

different origins;

one function

Homologs:

one origin;

different functions

One origin;

one function

Related species

Unrelated species

Related species

Divergence

Charles Darwin's doctrine of divergence is based on the principle of monophyly, according to which all species belonging to the same genus are descendants of one original species and genera of the same family descended from a common trunk.

The only illustration for Charles Darwin's book On the Origin of Species... (1859): a diagram of the divergence of species.

Divergence

The most divergent forms have greater opportunities to leave offspring and survive due to less competition among themselves. Intermediate forms most often die out.

Brown

White

Panda

Grizzly

Convergence

Due to convergence, organs that perform the same function in different organisms acquire a similar structure.

For example, in the swimming fossil reptiles ichthyosaurs and in the mammals dolphins, the shape of the body and forelimbs in the process of evolution acquired a convergent resemblance to the body shape and fins of fish.

dolphin

ichthyosaur

shark

Parallelism

Through parallelism, adaptations to the aquatic lifestyle developed in various pinnipeds (walruses, eared and true seals).

The group is believed to be polyphyletic: walruses and sea lions descended from bears, and seals from mustelids.

Pinnipeds: 1 – sea hare;

2 – tevyak;

3 – common seal;

4 – ringed seal;

5 – white-bellied seal;

6 – lionfish;

7 – crested cat (male);

8 – crested cat (female);

9 – Weddell seal;

10 – crabeater seal;

11 – leopard seal;

12 – southern sea lion;

13 – sea lion;

14 – walrus; 15 – elephant seal.

Macroevolution –

an evolutionary process leading to the formation of taxa of supraspecific rank (genera, orders, classes, etc.).

It is carried out on the basis of microevolution processes.

The subject of the study of macroevolution is interspecific relations as a factor of natural selection, conditions for the emergence, paths and patterns of historical development of systematic groups at the supraspecific level (genera, families, orders, etc.).

Lobe-finned fish -

coelacanth

Main directions and paths of evolution

A.N. Severtsov and I.I. Schmalhausen developed a doctrine about the main directions of evolution - biological progress and regression and the ways of their implementation - aromorphosis, idioadaptation, degeneration

Directions of the evolutionary process

Biological regression

Biological progress

• characterized by a decrease

level of adaptability to

living conditions, in

resulting in:

• numbers are decreasing

individuals of a species;

• its range is shrinking;
• the number decreases and

the diversity of its populations.

Biological regression leads to the extinction of a species.

• characterized by increasing

fitness of organisms

to the environment,

as a result:

• numbers are increasing

individuals of a species;

• its range is expanding;
• new populations are formed,

kinds.

Ways to achieve biological progress

Arogenesis –

characterized by the occurrence of aromorphoses - complication of the structure and functions of the body, increasing the general level of organization and expanding the habitat of this group of organisms. Aromorphoses. increasing the vital activity of organisms, they determine their relative independence from environmental conditions.

Allogenesis –

development path without increasing the overall level of the organization. associated with the appearance of idioadaptations - particular adaptations to certain environmental conditions.

Catagenesis –