Presentation for the lesson "Charles Darwin: the main provisions of the theory of speciation." Presentation "Evolutionary theory of Charles Darwin. Evidence of evolution Evolutionary theory of Charles Darwin presentation

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Introduction

Evolutionary theory as a discipline studies the general laws and driving forces of the historical development of life. Major sections of evolutionary theory are the history of the emergence and development of evolutionary ideas, the concept of micro- and macroevolution, phylogenetics. The purpose of the evolutionary theory is to identify the patterns of development of the organic world for the subsequent management of this process. The evolutionary theory solves the problems arising from the need to understand the general laws of evolution, the causes and mechanisms of transformation of living things at all levels of its organization.

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Charles Robert Darwin (English Charles Robert Darwin; February 12, 1809 - April 19, 1882) - English naturalist and traveler, one of the first to realize and clearly demonstrated that all types of living organisms evolve in time from common ancestors.

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Preconditions for the emergence of Charles Darwin's theory:

1) discoveries in biology (cellular structure of organisms, the similarity of animal embryos, fossil organisms);

2) the work of the geologist C. Lyell on the evolution of the Earth's surface under the influence of natural causes (t, wind, precipitation, etc.);

3) the development of capitalism, agriculture, selection

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The history of the creation of evolutionary theory

The basis for the creation of the theory of evolution was his observations during his round-the-world voyage on the ship "Beagle". He began the development of evolutionary theory in 1837, and only twenty years later, at a meeting of the Linnean Society in London, Darwin read a report containing the main provisions of the theory of natural selection.

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Evolutionary theory of Charles Darwin

1842 - the 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 unlimited deviation from the original type", which contained theoretical provisions similar to Darwinian ones.
• 1858 - Charles Darwin received his article from A.R. Wallace.
• 1859 - the first edition of the book "The Origin of Species"
• Alfred Wallace (1823-1913, England)
• Charles Darwin (1809-1882, England)

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1. Each type of organism is capable of unlimited reproduction. In this case, traits from parents are passed on to descendants (heredity)

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2. Descendants of the same parents are different (hereditary variability)

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3. Lack of vital resources leads to the struggle for existence

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Forms of struggle for existence

• Intraspecific (between individuals of the same species)
• Interspecies (between individuals of different species)
• Coping with adverse conditions (t, lack of water and food, etc.)

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Charles Darwin's doctrine of natural selection:

4. In the struggle for existence, the individuals most adapted to these conditions survive (natural selection)

The result is an increase in the adaptability of individuals to living conditions and the formation of new species

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Natural selection is the main driving force behind evolution

• The result of natural selection
• Adaptation for the survival and reproduction of offspring
• Divergence - the gradual divergence of groups of individuals according to individual characteristics and the formation of new species

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The Importance of Artificial Selection in the Creation of Darwin's Theory

• Artificial selection is the process of creating new breeds (varieties) by systematic selection and reproduction of individuals with traits valuable to humans
• From the analysis of a huge amount of material on the creation of breeds and varieties, Darwin extracted the principle of artificial selection and, on its basis, created his own evolutionary doctrine.

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Charles Darwin's doctrine of artificial selection:

1.all breeds (varieties) of one type of organism have one common ancestor

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2. Breeds (varieties) are created by humans by selection among the offspring of those individuals that have a set of traits that are valuable to humans (artificial selection)

• Unconscious selection is selection that does not aim to create a new variety or breed. People keep the best, in their opinion, individuals and destroy (discard) the worst (more milk-producing cows, better horses)
• Methodical selection is a selection carried out by a person according to a specific plan, for a specific purpose - to create a breed or variety

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3.the diversity of offspring is explained by different combinations of traits from the parents and mutations (hereditary variability)

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4.individuals selected by humans for reproduction will pass on their traits to descendants (heredity)

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Significance of Darwin's evolutionary theory

Darwin was the first in the history of biology to build a theory of evolution. This was of great methodological importance and allowed not only to clearly and convincingly for contemporaries substantiate the idea of ​​organic evolution, but also to verify the validity of the theory of evolution itself. This was a decisive phase in one of the greatest conceptual revolutions in natural science. The most important thing in this revolution was the replacement of the theological idea of ​​evolution as a concept of primordial expediency with the model of natural selection.

It is also Darwin's merit that he revealed the driving forces of organic evolution. Further development of biology deepened and supplemented his ideas, which served as the basis of modern Darwinism. In all biological disciplines, the leading place is now occupied by the historical method of research, which makes it possible to study specific paths of evolution of organisms and penetrate deeply into the essence of biological phenomena.

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Conclusion

Charles Darwin developed a harmonious and comprehensive concept of the formation of species, laid the foundation for a rigorous scientific approach to the study of the problem of species and speciation.

Darwin proposed a coherent theory of the emergence and development of new species and thereby approved the evolutionary approach in biology. As a result, not only in biology, but also in science as a whole, evolutionary thinking was formed. Evolutionary theory has become an axis or synthetic center for the development of biology and other scientific disciplines. This is its absolute significance for the development of science.

From its inception to the present, Darwin's theory has caused much controversy and controversy. There are a variety of views regarding it - from widespread acceptance to complete denial. In particular, the problem of the qualitative uniqueness of the species and the qualitative features of the process of speciation, which has been in the center of attention since the time of Darwin, has not yet been resolved.

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Bibliography

1. A. V. Yablokov, B. M. Mednikov. Charles Darwin. The origin of species by natural selection. M., "Education", 1987.

2. Charles Darwin. Origin of species. M.-L., Selkhozizd, 1952, p. 14.

3. Yu.I. Polyansky. General biology. M., "Education", 1993.

4. Charles Darwin. A naturalist's journey around the world aboard the Beagle. Per from English., M., "Thought", 19

Biography of Charles Darwin - studies medicine in Edinburgh; - studies medicine in Edinburgh; years - travel on the ship "Beagle"; years - travel on the ship "Beagle"; 1837 – becomes a committed evolutionist 1837 – becomes a committed evolutionist and begins to look for the driving force behind evolution; 1839 - publishes travel descriptions; 1839 - publishes travel descriptions; 1858 is the year of birth of the evolutionary theory; 1858 is the year of birth of the evolutionary theory; 1971 - "Human Descent and Sexual Selection." 1971 - "Human Descent and Sexual Selection."

A "struggle for existence" arises between individuals. The consequence of the struggle for existence is "natural selection". The result of natural selection: - the adaptation of organisms to specific conditions of existence; - The variety of species that inhabit the Earth.

Significance of Charles Darwin's teachings He revealed the driving forces of evolution; Revealed the driving forces of evolution; Explained the emergence of the adaptation of living organisms to the external environment and its relative nature. Explained the emergence of the adaptation of living organisms to the external environment and its relative nature.

"Evolution of the organic world" -? Embryological Paleontological Biogeographic Comparative anatomical. 3. 5. 6. Blind cave fish. 7. 8. Cassowary is an Australian ostrich. Wing? Polymastia is an accessory pair of mammary glands. Evolution. 12.

"Development of the plant world" - Plant. Spore plants. Seed plants. The development of the plant world on Earth. Lesson topic. Arrange in the right order: Mira. The evolution of the plant world. Gymnosperms. Mosses. Stages. Lesson Objectives:

"Darwin's theory of evolution" - Formation of new species. The process of historical changes is carried out from simple to complex in accordance with the principle of gradation. Answer: The driving forces of evolution have been identified. 5. Both favorable and unfavorable changes can be inherited. The regularities of transformation of one organic form into another are revealed.

"Evolution of Species" - This speciation is always rather slow. Basic laws of biological evolution. Macroevolution. - the formation of large systematic groups: types, classes, detachments. Basic rules of evolution: Species criteria: Reproductive - genetic isolation of one species from others, even closely related ones.

"Darwin's Theory" - Forms of variability (according to Darwin). The mechanism of evolution (according to the theory of Charles Darwin). It is caused by the influence of the external environment. Evolution results. 1859 - "The Origin of Species by Natural Selection." For evolution, only hereditary (indeterminate) variability matters. Hereditary variability.

Evolutionary doctrine

Charles Darwin.

Evidence for evolution

Teacher Smirnova Z.M.

Creation of evolutionary theory

Teaching created

C. Darwin and A. Wallace

1858 - On July 1, at the Meeting of the Linnaean Society, the concepts of Charles Darwin and A. Wallace on the emergence of species by natural selection were presented.

1859 - the first edition of the book "The Origin of Species by Natural Selection"

Charles Darwin

1809-1882

Alfred Wallace

(1823-1913)

Prerequisites for the emergence of the theory

C. Darwin

Socio-economic:

1. Development of capitalism (search for sales markets, sources of raw materials);

• Organization of trips around the world, participation

C. Darwin

3. Practice of breeders: creation of animal breeds and plant varieties.

Scientific background:

1. Cellular structure of organisms (R. Hooke, A. Levenguk);

2. The similarity of animal embryos (K. Baer);

3. Discoveries in the field of comparative anatomy of paleontology (J. Cuvier);

4. Geologist C. Lyell proved that the earth's surface is constantly changing under the influence of natural processes (t, wind, precipitation, etc.).

"Beagle"

Charles Lyell (1797-1875)

Creation of evolutionary theory

Charles Darwin's main merit is that he revealed the driving forces of evolution. He materialistically explained the emergence and relative nature of fitness by the action of only natural laws, without the intervention of supernatural forces.

Darwin's teaching fundamentally undermined the metaphysical ideas about the constancy of species and their creation by God.

The model of the processes occurring in nature, served for Darwin, the practice of agriculture

in England.

The driving forces behind the evolution of varieties and breeds

Variability: Artificial Selection

– undefined

(genotypic); Conscious Unconscious

– certain - held in – man not

(modification); accordance with puts before

– relative the goal set by oneself, and

(correlative) purpose, simply eliminates

targeted less valuable

breeder and leaves

the best for the tribe

Human selection is called artificial.

Artificial selection - directed accumulation of traits

for the benefit of the person.

The result of breeding work

Savoy

White-headed

Redhead

Wild cabbage

Kohlrabi

Colored

Beijing

Broccoli

Brussels

Formation of new species in natural conditions

The study of artificial selection helped Charles Darwin to understand the driving forces behind the formation of species in natural conditions:

All creatures have a certain level of individual variability;

Traits from parents are passed on to descendants by inheritance;

Each type of organism is capable of unlimited (there are 3000 seeds in a box of poppy, sturgeon spits out 2 mln. eggs);

Lack of vital resources leads to a struggle for Existence;

In the struggle for existence, the most survive

individuals adapted to these conditions.

Driving forces of species evolution

Natural selection -

Hereditary variability:

the main guiding factor of evolution

combinative,

mutational

Struggle for existence

Interspecific

– occurs between

individuals

other species with

the same needs

Intraspecific

– occurs between

individuals of the same species for territory, food, female

Fight against unfavorable environmental conditions - the strongest and hardiest individuals survive in the fight against drought, flooding, cold

result

Darwinian concept of natural selection

The material for evolution is uncertain variability;

Natural selection is a consequence of the struggle for existence, selective destruction of some individuals and preferential reproduction of others, most adapted to the environment of existence.

Struggle for existence

Natural selection

consequence

Fitness organisms to the environment, diversity of species

Forms of natural selection

Natural selection is the only creative factor in evolution, directing random hereditary changes towards the formation of adaptations.

Forms of natural selection

Moving

selection

Disruptive (disruptive)

Stabilizing

Forms of natural selection - driving selection

Driving selection - acts in changing environmental conditions and contributes to a shift in the average value of a trait and the emergence of new forms.

Forms of natural selection - stabilizing selection

Stabilizing - operates under constant environmental conditions.

The selection is directed against extreme variants and favors individuals with average values ​​of the trait.

In insect pollinated plants, the size and shape of the flower are stable. Flowers that do not correspond to the structure of pollinating insects, do not form seeds, therefore, the genes that caused the deviation from the norm are eliminated from the gene pool of the population. This form of selection is described by I. Schmalhausen (1946).

Forms of natural selection - disruptive (disruptive) selection

Disruptive (tearing) - acts in a territory with a variety of living conditions. It is aimed at selecting not one trait, but several different ones, each of which is conducive to survival. The mean value of the feature is eliminated.

Seeds

Leaves

Kidneys / fruits

Larvae

Comparison of artificial and natural selection

Peculiarities

Artificial selection

Selection material

Natural selection

Hereditary and non-hereditary variability

Selects

Hereditary variability

Man

Result

Environment conditions

Individuals with traits valuable for humans

Are selected

The fittest individuals

New varieties and breeds

New species,

adaptation to environmental conditions

The fitness of organisms

to the habitat

According to Lamarck: the driving force of evolution is the desire of organisms for perfection.

Example: giraffes, when getting food, had to constantly stretch their necks in order to reach the leaves of tall trees (exercise). The trait is inherited.

According to Darwin: among the giraffes there were animals with necks of different lengths. Those with slightly longer necks were more successful in foraging and surviving. This trait was inherited. So, gradually, a long

neck of giraffes.

The relative nature of the fitness of species

The position of Charles Darwin - fitness (expediency) always has a relative character.

Any adaptation is useful only in the conditions in which it arose; when conditions change, it ceases to be useful or even becomes harmful to the body (the hare is invisible to predators in the snow, it is clearly visible against the background of tree trunks and dark earth in a snowless winter).

Forms of devices

• Morphological adaptations - structural changes

body (streamlined body shape in fish and birds).

• Disguise - body shape and color merge with surrounding objects (seahorse, stick insects)

Forms of devices

• Protective coloring - developed in species that live openly and may be available to enemies (flounder, grasshopper). If the background of the environment is not constant depending on the season of the year, the animals change their color (white hare, brown hare).

Forms of devices

• Warning coloring - bright, characteristic of poisonous and stinging forms (wasps, bumblebees, rattlesnakes).

 Mimicry - similarity in color, body shape of unprotected organisms with protected ones (hoverfly fly).

Deadly Texas Coral Snake

Harmless Mexican Milk Snake

Evidence for evolution

• Morphological (comparative anatomy);

• Embryological;

• Paleontological;

• Biochemical;

• Biogeographic;

• Molecular genetic evidence

Morphological evidence

(comparative anatomy)

General plan of the structure of vertebrates

Similar and homologous organs

Rudiments

and atavisms

• General plan of the structure of vertebrates:

• bilateral body symmetry,
• spine,
• secondary body cavity,
• nervous,
• circulatory, etc.;

Evidence for evolution

Comparative anatomy

• Homologous organs – are similar in structure and origin, regardless of the function performed (the skeleton of the forelimb of vertebrates).

Homologous organs

Man Cat Whale Flying

mouse

Evidence for evolution

Comparative anatomy

• Similar bodies have a different structure and origin, but perform the same functions (gills of fish and crayfish; wings of a bird and a butterfly). Similar bodies are the result of convergence.

Similar bodies

mole bear

Butterfly wing

Bird wing

Evidence for evolution

Comparative anatomy

• Rudiments - disappearing organs, which in the process of evolution have lost their significance for the preservation of the species (the first and third fingers in birds in the wing, the second and fourth fingers in a horse, pelvic bones in a whale);

Rudiment

megalomaniac

membranes

Ear

muscle

Coccyx

Evidence for evolution

Comparative anatomy

• Atavisms - the appearance in modern organisms of the signs of ancestors (highly developed hairline, multi-nipple in humans).

• K. Baer (1828), comparing embryos of different classes, formulated the "law of embryonic similarity":

In the early stages of development, the embryos of various groups of vertebrates are similar to each other.

Embryological evidence

F. Müller and E. Haeckel(1866) on this discovery they formulated a biogenetic law: ontogeny (individual development of organisms) repeats phylogeny (historical evolutionary development of a group).

A. N. Severtsev clarified that in the individual

development, the development of non-adults is repeated

stages, and embryonic.

allow you to describe the events of ancient history

on the fossil remains of organisms.

Paleontological evidence for evolution

Transitional forms -

organisms that occupy an intermediate position between large systematic groups

Fossil remains - remains and traces

vital activity of organisms

Past geological eras.

Phylogenetic series - rows of species successively replacing each other.

Fossil remains

Fossil remains - the basis for restoring the appearance of ancient organisms. The similarity between fossils and modern organisms is proof of their relationship. The antiquity of fossil remains is established by the age of the rocks,

in which they are found.

The spread of ancient, primitive organisms in the deepest layers of the earth's crust, and highly organized -

in later layers

Paleontological evidence

Fossil transitional forms

– Evidence material about the successive relationships between different groups of organisms, combine the signs of more ancient and younger groups.

For example, a transitional form from reptiles to birds is the Jurassic first bird - Archeopteryx the size of a dove, with a long, like a reptile's tail and developed teeth. His body was covered with feathers, and his forelimbs turned into wings.

Stegocephalus -

transitional form between cross-finned fish and amphibians

Paleontological evidence

modern

horse

Phylogenetic series of a horse

The evolution of horses is well documented by fossils, which show how the small, dog-sized forest animal, the eohyppus, with its toes instead of hooves, evolved over 50 million years into large, hoofed inhabitants of open spaces.

hipparion

merikhippus

mesohippus

eogippus

The predecessor of the horse

Phylogenetic series:

Cetacean Human

Biogeographic

evidence for evolution

The spread of animals and plants on the surface of the Earth reflects the process of evolution.

Wallace divided the earth's surface into 6 zoogeographic zones:

• Holarctic zone (North America);
• Ethiopian (Central and South Africa);
• Australian (Australia, Tasmania, New Zealand);
• Indo-Malay (India);
• Neotropical (South and Central America).

Biogeographic

evidence for evolution

The closer the connection between continents, the more related species live on them, the more ancient the isolation, the greater the differences between animals and plants. The fauna of the Australian zone is the most peculiar.

Molecular genetic

evidence for evolution

All living organisms are composed of cells, have a universal genetic code, common mechanisms for storing, implementing and transmitting genetic information.

2 human chromosome is the product of the fusion of two monkeys and the cross-striation of all chromosomes in both species is very close. Such insignificant differences in the structure of the karyotype usually characterize extremely closely related species.

Comparison of chromosome sets

human (left) and chimpanzee (right)