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Topic 1. Basics of evolutionary teaching LESSON. Formation of evolutionary views The concept of “evolution” means a gradual, natural transition from one state to another. The term “evolution” was introduced into biology by the Swiss naturalist C. Bonnet (1762). Evolution comes from the Latin word for “unfolding.” Irreversible and directed development of the organic world
Pre-Darwinian period Thanks to the works of Aristotle and his students, the beginnings of comparative anatomy and embryology, the doctrine of the correspondence of organisms, and the idea of gradation arose. Of particular note is the development of general principles of classification, which he applied to animals, and his student Theophrastus - to plants. For Aristotle, species did not have the meaning of the main systematic unit. The Great Geographical Discoveries played a huge role in the accumulation of scientific facts. The period of accumulation of knowledge about various plants and animals entered science as a descriptive, inventory period. CONCLUSION. The accumulation of factual material put forward the need to create scientific terminology and a system of plants and animals
Pre-Darwinian period The English biologist J. Ray was the first to reduce species to the rank of a biological concept. Three features of the species were established: the association of many individuals; morphological and physiological similarities between them; ability for general reproduction and reproduction of offspring that retains similarity with parental forms 1627 - 1705
Pre-Darwinian period C. Linnaeus is the author of the best artificial taxonomy of his time. He identified 24 classes of plants and 6 classes of animals according to several separate arbitrarily chosen characters. Linnaeus established the reality of species, clearly emphasized the reproductive isolation between them, discovered their stability, prepared the ground for raising the problem of their origin, and introduced scientific terminology (taxa - species, genus, order , class), and their hierarchy. New species can be formed through crossing. Species is a unit of classification. He proposed a double (binary) nomenclature for naming species. He classified humans into the order of primates, the class of mammals. Disadvantages of Linnaeus's work are considered to be 1. Creationism - all species are unchanged, created by a creator. 2. Adaptability of organisms - initially expedient 1707-1778
Pre-Darwinian period J.B. Lamarck is the author of the first evolutionary doctrine. Introduced the terms “biology” and “biosphere”. The main direction of the evolutionary process is gradual complication from lower to higher. He divided animals into 14 classes, which he placed on 6 gradation levels according to the degree of complexity of the nervous and circulatory systems. He proposed the idea of historical development: “Species change, but very slowly, so it’s not noticeable.” Thus, he correctly assessed the importance of time, but believed that species do not really exist, since they are constantly changing as a result of the direct influence of the environment. The driving forces of evolution are: The initial desire for self-improvement. The appropriate reaction of organisms to the environment: exercise or non-exercise of organs. Fortunately, acquired characteristics are inherited. Jean Baptiste Pierre Antoine de Monet Chevalier de Lamarck 1744 - 1829
The main provisions of the evolutionary teachings of Charles Darwin Charles Darwin is an English naturalist, the founder of the Theory of Evolution. During his trip around the world (1831-1836), he collected rich scientific material, which became the basis of his main work, “The Origin of Species” (1859). Evolution, according to Charles Darwin, consists of continuous adaptive changes in species. The main provisions of the teachings of Charles Darwin 1. Prerequisite for evolution: hereditary (individual) variability 2. Driving forces: the struggle for existence and natural selection 3. Evolution is a gradual complication and increase in the organization of living beings (evolution has a progressive nature) Variability Group (non-hereditary, definite ) Individual (hereditary, indefinite) Correlative (correlation) A similar change in all individuals of the offspring in one direction due to the influence of certain conditions. The appearance of various minor differences in individuals of the same variety, breed, species, by which, existing in similar conditions, one individual differs from others. The possibility of various deviations cannot be excluded. A change in the structure or function of one part often also causes certain changes in others.
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History Changing scientific ideas about the origin and development of life on Earth All living things were created at the same time by some Higher Power and are not subject to change (Creationism) Life originated a long time ago and, as a result of natural processes, was divided into a huge number of species (Evolutionism)
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Development of evolutionary concepts Developed a taxonomy of living organisms. The systematic arrangement of species made it possible to understand that there are related species and species characterized by distant relationships. The idea of kinship between species is an indication of their development over time. Carl Linnaeus (1707 - 1778)
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Development of evolutionary concepts Jean-Baptiste Lamarck (1774-1829) Author of the first evolutionary concept. He argued that the organs and organ systems of animals and plants develop or degrade as a result of their exercise or lack of exercise. The weak point of his theory was that acquired characteristics cannot actually be inherited:(
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Development of evolutionary concepts The author of the first coherent evolutionary concept was Charles Darwin, who wrote a book on this subject: “On the Origin of Species by Means of Natural Selection, or the Preservation of Favored Breeds in the Struggle for Life” Charles Darwin (1809 - 1882)
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The basic logic of evolutionary teaching is Heredity Variability The ability of organisms to reproduce unlimitedly Limited environmental conditions Organisms differ from each other and can pass on their characteristic features to their descendants Struggle for existence Survival of the fittest Natural selection
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Natural selection In summary: Living systems adapt to environmental conditions. There are a huge number of species of living organisms on planet Earth. Highly organized species and species with a more primitive level of organization can coexist
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Evidence of evolution: Morphological (comparative anatomical) Homologous and similar organs Atavisms Rudiments
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Target. To acquaint students with the emergence and development of evolutionary ideas, the evolutionary teachings of Charles Darwin.
Methods. Lesson-lecture.
During the classes
1. Explanation
- Lecture plan.
- Terms
- Aristotle and organic evolution
- Carl Linnaeus is the forerunner of evolutionism.
- Evolutionary doctrine of J.B. Lamarck.
- Evolutionary doctrine of Charles Darwin
First, let's get acquainted with the new terms of the topic.
Creationism- the doctrine that life was created by a supernatural being at a specific time.
Metaphysical worldview– (Greek “physis” - nature; “meta” - above) – the original and absolute purposiveness, and therefore the constancy and immutability of all nature.
Transformism- the doctrine of the transformation of one species into another.
Evolution– (lat. evolvo - deploy /evolutio/ - deployment) a historical change in the form of organization and behavior of living beings in a series of generations.
Aristotle and organic evolution
The new branch of biology is called evolutionary doctrine, or Darwinism, since the theory of evolution was established in biology thanks to the work of the outstanding English scientist Charles Darwin. However, the very idea of evolution is as old as the world. The myths of many peoples are permeated with ideas about the possibility of transformation (transformation) of one species into another. The beginnings of evolutionary ideas can be found both in the works of thinkers of the Ancient East and in the statements of ancient philosophers. 1000 BC e. in India and China It was believed that man descended from apes.
Why do you think?
It’s similar in India, the monkey is a sacred animal and it’s even honorable.
Ancient Greek thinker, philosopher, founder of biology, father of zoology Aristotle (384–322 BC) formulated a theory of the continuous and gradual development of living things from inanimate matter, based on his observations of animals. At the same time, he proceeded from the metaphysical concept of the desire of nature from the simple and imperfect to the more complex and perfect. Aristotle recognized the evolution of the earth's strata, but not the evolution of living organisms, although in his “Ladder of Nature” he grouped and arranged inanimate matter and all living organisms in a certain order from primitive to more complex, which suggested a relationship between living organisms.
Carl Linnaeus is the forerunner of evolutionism.
Carl Linnaeus - Swedish scientist (1707-1778) - the father of botany, the king of flowers, the great systematizer of Nature.
He proposed a simple classification scheme for animals and plants, the best of all previous ones.
a) Linnaeus considered the main systematic unit to be species (a set of individuals similar in structure and producing fertile offspring). The view exists and does not change.
b) He united all species into genera, genera into orders, orders into classes.
c) Linnaeus classified the whale as a mammal, although in the 17th century the whale was considered a fish.
d) Linnaeus, for the first time in the history of science, placed man first in the order of primates in the class of mammals, along with monkeys and prosimians, on the basis of the similarities between man and monkey.
Linnaeus applied a clear, convenient principle of double names.
Before Linnaeus, scientists gave plants only generic names. They were called: oak, maple, rose, pine, nettle, etc. Science used the names of plants by genus, just as is usually done in colloquial everyday language; in relation to plants and animals, long descriptions of characteristics were used to designate the species. So, before Linnaeus, the rose hip was called “Common forest rose with a fragrant pink flower.”
Linnaeus left generic names. He proposed that species names be given in words (most often adjectives) denoting the characteristics of a given plant or animal. The name of plants or animals now consisted of 2 words: in the first place was the generic name (noun), in the second place was the specific name (usually an adjective). For example, Linnaeus named the rosehip in Latin Rosa canina L (Dog rose). L stood for the name of the author who gave the name to this species. In this case Linnaeus.
The very idea of double names was proposed by Kaspar Baugin, i.e. 100 years before Linnaeus, but only Linnaeus realized it.
Linnaeus created the science of botany in the place of former chaos.
a) Conducted a huge reform in the botanical language. In the book "Fundamentals of Botany" he lists about 1000 botanical terms, clearly explaining where and how to use each of them. In fact, Linnaeus invented, albeit taking into account the old terminology, a new language for natural science.
b) Worked on issues of plant biology. Suffice it to recall the "Flora Calendar"
"Clock of flora", "Dream of plants". He was the first to propose conducting phenological observations to determine the best timing of work for agricultural plants.
c) Wrote several large textbooks and study guides on botany.
Linnaeus' system aroused enormous interest in the study and description of plants and animals. Thanks to this, the number of known plant species increased from 7,000 to 10,000 in a few decades. Linnaeus himself discovered and described about 1.5 thousand species of plants, about 2000 species of insects.
The line aroused my interest in studying biology. Many famous scientists, philosophers, and writers became interested in the study of nature thanks to their acquaintance with the works of C. Linnaeus. Goethe said: “After Shakespeare and Spinoza, Linnaeus made the strongest impression on me.”
Despite the fact that Carl Linnaeus was a creationist, the system he developed is alive
nature was built on the principle of similarity, had a hierarchical structure and suggested a relationship between close species of living organisms. Analyzing these facts, scientists came to the conclusion about the variability of species. The authors of these ideas considered the change in species over time as a result of the unfolding (from the Latin “evolvo” - unfolding) of a certain preliminary plan of the Creator, a pre-compiled program in the course of historical development. This point of view is called evolutionist. Such views were expressed in the 18th century. and at the beginning of the 19th century. J. Buffon, W. Goethe, K. Baer, Erasmus Darwin - grandfather of Charles Darwin. But none of them offered a satisfactory explanation of why and how species changed.
Evolutionary doctrine of J.B. Lamarck.
The first holistic concept of evolution was expressed by the French naturalist Jean Baptiste Pierre Antoine de Monier Chevalier de Lamarck (1744-1829).
Lamarck was a deist and believed that the creator created matter according to the laws of its movement, this ended the creative activity of the creator, and all further development of nature occurred in accordance with its laws. Lamarck believed that the most primitive and simple organisms arise through spontaneous generation, and such spontaneous generation occurred many times in the distant past, is happening now and will happen in the future. Organisms, according to Lamarck, could arise from inanimate matter under the influence of light, heat, and electricity.
After their appearance, primitive living organisms do not remain unchanged. They change under the influence of the external environment, adapting to it. As a result of this change, living organisms gradually improve over time over a long series of successive generations, becoming more and more complex and highly organized. As a result, the more time passes from the moment a certain form appears through spontaneous generation, the more perfect and complexly organized its modern descendants turn out to be. The most primitive modern living organisms, in his opinion, arose quite recently and simply did not yet have time to become more perfect and highly organized as a result of gradual complication. All these changes occur over a long period of time and are therefore invisible. But carried away by the denial of the constancy of species, Lamarck begins to imagine living nature as continuous rows of changing individuals; he considers species to be an imaginary unit of classification convenient for the nomenclature of organisms, and in nature only individuals exist. The species is constantly changing and therefore does not exist - he writes in “Philosophy of Zoology” (1809). Lamarck called the stepwise nature of the complication of the organization of living beings gradation. Another new term.
Gradation(lat. ascent) - increasing the organization of living beings from the lowest level to the highest in the process of evolution.
Driving forces of evolution according to Lamarck.
Inner desire for progress, that is, every living creature has an innate internal desire to complicate and improve its organization; this property is inherent in them from the very beginning of nature.
Influence of the external environment, thanks to which, within the same level of organization, various species are formed, adapted to living conditions in the environment.
Any change in the external environment causes organisms only useful changes traits that are inherited as innate properties and only adequate changes, i.e. those that correspond to the changed conditions.
In plants and lower animals The reason for continuous complication and improvement is direct influence of the external environment, causing changes that provide more perfect adaptation to these conditions. Lamarck gives such examples. If the spring was very dry, then meadow grasses grow poorly; spring, with alternating warm and rainy days, causes the same grasses to grow vigorously. Getting from natural conditions into gardens, plants change greatly: some lose thorns and thorns, others change the shape of the stem, the woody stem of plants in hot countries becomes herbaceous in our temperate climate.
In higher animals the external environment valid indirectly involving the nervous system. The external environment has changed - and animals have new needs. If new conditions remain in effect for a long time, then animals acquire corresponding habits. At the same time, some organs are exercised more, others less or completely inactive. An organ that functions intensively develops stronger and becomes stronger, while an organ that is little used for a long time gradually atrophies.
Lamarck explained the formation of a swimming membrane between the fingers of waterfowl by stretching the skin; the absence of legs in snakes is explained by the habit of stretching their body when crawling on the ground, without using their limbs; The giraffe's long front legs are due to the animal's constant efforts to reach the leaves on the trees.
J.B. Lamarck also assumed that the desire of an animal leads to an increased flow of blood and other “fluids” to the part of the body to which this desire is directed, which causes increased growth of this part of the body, which is then inherited.
Lamarck was the first to use the terms “kinship” and “family ties” to denote the unity of origin of living beings.
He quite correctly believed that environmental conditions have an important influence on the course of the evolutionary process.
Lamarck was one of the first to correctly assess the importance of time in the process of evolution and noted the extraordinary duration of the development of life on earth.
Lamarck’s ideas about the branching of the “ladder of beings” and the non-linear nature of evolution prepared the way for the idea of “family trees”, developed in the 60s of the 19th century.
J.B. Lamarck developed a hypothesis about the natural origin of man, suggesting that the ancestors of man were monkeys who switched to a terrestrial lifestyle and walking on the ground from climbing trees. This group (breed) used its hind legs for walking for a number of generations and eventually went from being four-armed to being two-armed. If this breed stopped using its jaws to tear apart prey and began to chew it, this could lead to a decrease in the size of the jaw. This most developed breed took over all convenient places on earth, displacing less developed breeds. Individuals of this dominant breed gradually accumulated ideas about the world around them; they developed a need to convey these ideas to their own kind, which led to the development of various gestures, and then speech. Lamarck pointed out the important role of the hand in the development of man.
He tried to explain the origin of domestic animals and cultivated plants. Lamarck said that the ancestors of domestic animals and cultivated plants were taken by man from the wild, but domestication, changes in diet and crossing made these forms unrecognizable in comparison with wild forms.
Evolutionary doctrine of Charles Darwin.
2. Charles Darwin about the species.
The view exists and changes
Driving forces of evolution according to Charles Darwin.
- Heredity.
- Variability.
- Natural selection based on the struggle for existence.
3. Homework assignment. Paragraphs 41, 42 to art.
4. Consolidation.
- What did Aristotle think about the evolution of living organisms?
- Why is Carl Linnaeus called the herald of evolutionism?
- Why is the evolutionary teaching of J.B. Lamarck was not recognized by his contemporaries?
- What do you know about the evolutionary teachings of Charles Darwin?
( pre-Darwinian period ).
Species and populations
Teacher Smirnova Z.M.
Basics of evolutionary teaching
The doctrine of evolution is the doctrine of the historical development (evolution) of living nature.
Lobe-finned fish –
coelacanth
Development of evolutionary ideas
Ideas for the development of living nature can be traced in the works of philosophers of Ancient India and China
(2nd millennium BC)
The works of ancient philosophers had an influence on the development of evolutionary
(VII – I centuries BC), Heraclitus, Empedocles, Aristotle.
Development of evolutionary ideas
Aristotle for the first time
- put forward a theory about the development of animals from simple to complex forms;
- tried to systematize and generalize knowledge about plants and animals and came up with a “ladder of creatures”, on the steps of which organisms are located in accordance with the level of organization they have achieved.
Heraclitus argued that
- everything arises through struggle and out of necessity ;
- for the first time introduced into philosophy and the science of nature a clear idea of constant change.
Aristotle
Heraclitus
Ephesian
Development of evolutionary ideas
The evolution according to Empedocles (~450 BC) of the animal world consists of four periods:
- period of single-member organs,
- period of monsters,
- the period of all-natural beings and
- period of sexual differentiation.
Apparently, the division of animals into species according to their place of life (in water, on land and in the air) should also be dated to the fourth period.
Empedocles found the idea of survival of the fittest organisms.
Empedocles
(490-430 BC)
Development of evolutionary ideas
John Ray
50 years before K. Linnaeus, he singled out classification as an independent scientific discipline - the science of dividing organisms into groups in accordance with certain criteria (comparative anatomical characteristics).
Ray clearly formulated the concept of the basic taxonomic unit - the species.
John Ray (1628-1705) – English scientist
A species, according to Ray (1693), is a collection of identical organisms capable of leaving offspring similar to themselves during the process of reproduction.
Development of evolutionary ideas
J. Buffon expressed progressive ideas about the variability of species under the influence of environmental conditions (climate, nutrition, etc.).
Buffon explained the similarity of mammals in Africa and South America by the fact that these continents once formed one whole (the modern theory of continental drift).
Georges Buffon (1707-1788) – French naturalist
Development of evolutionary ideas
Carl Linnaeus - Swedish naturalist
- Creator of the best artificial taxonomy - “System of Nature” (1735) - in it organic
nature is divided into kingdoms, classes, orders, genera and species. Recognized the real existence of species in nature.
- Introduced binary nomenclature – Genus-species.
Charles
Linnaeus
(1707-1778)
Disadvantages of the Linnaeus system:
- The system is artificial and does not reflect the real
kinship;
- He considered species to be unchangeable, created by a creator;
- In his taxonomy, the world was arranged from complex to simple.
Development of evolutionary ideas
Georges Cuvier played a big role in the creation paleontology and comparative anatomy;
improved the system of K. Linnaeus. Introduced a new taxonomic unit - type ("vertebrates" “articulated”, “soft-bodied” and “radiant”);
was the first to apply the comparative method and discover
organ correlation law – all structural and functional characteristics of the body connected by constant relationships.
Georges Cuvier
1769 -1832)
– French
zoologist
He proposed to determine age using fossil forms.
geological layers in which they are found.
To explain the change in flora and fauna in different periods evolution of the Earth, put forward catastrophe theory , after which the face of the planet was transformed.
Development of evolutionary ideas
Etienne Geoffroy Saint-Hilaire
Put forward the concept "theory analogues": animals are built according to the same morphological plan (homology), regardless of the form and function of these parts.
For example, the human hand, like a forelimb, is homologous to the foreleg of a horse, the wing of a bird, etc.
If you compare their anatomical structure, you can find homology in bones (bones of the shoulder, forearm and hand), muscles, blood vessels, nerves, etc.
Etienne J.
Saint Hilaire
(1772 -1844) –
French scientist
Theories origin of species
17-18 centuries battle of theories
creationism and transformationism
Transformism – the doctrine of the variability of plant and animal species and the possibility of transforming some species into others
Creationism – the concept of permanence of species, considering the diversity of the organic world as a result of its creation by God
Etienne J.
Saint Hilaire
(1772 -1844)
Georges Cuvier
1769 -1832)
Carl Linnaeus (1707-1778)
Georges Buffon (1707-1788)
The first scientific theory of the evolution of the organic world belongs to J.B. Lamarck (1809)
– "Philosophy of Zoology"
- Coined the term "Biology"
- Created a more advanced classification
animal world, noticing the main
direction of the evolutionary process – complication from lower to higher forms of life – gradation;
- For the first time recognized the variability of species on basis for the existence of transitional forms between species (paleontological finds)
Classification of animals according to Lamarck
14. Mammals
13. Birds
12. Reptiles
11. Pisces
10. Shellfish
9. Barnacles
8. Rings
7. Crustaceans
6. Arachnids
5. Insects
4 . Worms
3. Radiant
2. Polyps
1. Ciliates
Driving forces of evolution according to Lamarck:
- The desire of organisms to progress;
- Adaptation to environmental conditions
achieved by animals as a result of exercise or failure to exercise the organs ( Long neck
giraffe - the result of exercise while feeding
leaves from tall trees, which you need to reach
was to reach.
Poor vision of moles - the result
lack of exercise due to life underground.
- Inheritance of acquired characteristics.
The first scientific theory of evolution by J.B. Lamarck
Disadvantages of the teaching - failure of hypotheses:
about the internal desire of organisms to self-improvement;
inheritance of acquired characteristics;
Denied the real existence of species in nature, imagined nature as a collection of constantly changing series individuals. He considered only individuals to be real.
J. B. Lamarck failed to explain the driving forces of evolutionary development. Solved this problem
Charles Darwin, having developed the theory of natural selection.
Species Definition
A species is the basic structural unit of living nature.
It arises, develops, and when conditions of existence change, it can disappear or transform into other species.
A species is a collection of individuals that are similar in morphophysiological properties, have a common origin, occupy a specific area, interbreed freely and produce fertile offspring.
Type criteria
Some species differ from others by a number of characteristics - species criteria:
- Morphological 4. Genetic
2. Physiological 5. Ecological
3. Biochemical 6. Geographic
Morphological criterion
Morphological criterion is the similarity of the external and internal structure of individuals of the same species.
The criterion is not absolute, because There are twin species (malarial mosquito - 6 twin species) that are morphologically indistinguishable, and individuals of the same species can differ (sexual dimorphism).
Physiological criterion
Physiological the criterion is the similarity of life processes in individuals of the same species and the similarity of their reproduction.
Descendants from different species are usually sterile;
The criterion is not absolute, because There are species in nature that can interbreed
and leave fertile offspring:
wolf X dog
canary X finch fertile offspring
poplar X willow
Biochemical criterion
Biochemical criterion - allows you to distinguish species by the composition and structure of certain proteins, nucleic acids, etc. Individuals of one species have a similar DNA structure, which determines the synthesis of identical proteins that differ from proteins of another species;
The criterion is not absolute, because at For some bacteria, fungi, and higher plants, the DNA composition turned out to be very similar.
Geographical criterion
Geographical criterion – the species is widespread
in a certain territory (area).
The criterion is not absolute, because Individuals of different species can live in the same habitat. Individuals of the same species can occupy different habitats (for example, island populations). There are cosmopolitan species that live everywhere (for example, the red cockroach, the house fly). The ranges of some species are changing rapidly (for example, the range of the brown hare is expanding). There are bi-areal species (for example, migratory birds).
Ecological criterion
An ecological criterion is the adaptability of individuals of a species to certain living conditions. For example, morphologically similar species of buttercups - caustic buttercup and stinging buttercup - differ based on ecological criteria. Acrid buttercup is common in meadows and fields, pungent buttercup is found in marshy soil.
The criterion is not absolute, because different species can be adapted to the same conditions. Individuals of the same species can live in slightly different conditions (for example: deep sea and coastal
populations of river perch, dandelion can
grow both in forests and meadows).
Genetic criterion
Genetic criterion - based on the difference between species according to karyotypes, i.e., according to the number, shape and size of chromosomes.
The criterion is not absolute, because, firstly, in many different species the number of chromosomes is the same and their shape is similar. Thus, many species from the legume family have 22 chromosomes (2n = 22).
Secondly, within the same species there may be individuals with different numbers of chromosomes, which is the result of genomic mutations. For example, in silver crucian carp there are populations with a set of chromosomes 100, 150,200, while their normal number is 50.
Type criteria
Conclusion: in order to determine whether an individual belongs to a particular species, one criterion is not enough, it is necessary to take into account the totality of all criteria.
POPULATION
Each species is characterized by a specific habitat - habitat. Within the habitat there may be various barriers (rivers, desert mountains, etc.) that prevent free crossing between groups of individuals of the same species.
Such relatively isolated groups of individuals of the same species that exist for a long time in a certain territory are called populations.
Conditions within the range are heterogeneous
A species exists in the form of populations
POPULATION
Population is a collection of freely interbreeding individuals of the same species that exist for a long time in a certain territory relatively separately from other populations of the same species.
A population is the elementary structure of a species. Thus, a species consists of populations.
Populations of the same species are genetically heterogeneous, because Due to different living conditions, different gene alleles are subject to natural selection, so populations of the same species differ in different traits.
Slide 1
Pimenov A.V. Topic: “The emergence and development of evolutionary concepts” Objectives: To consider the emergence of diversity of species on Earth, the emergence of the amazing adaptability of organisms to certain living conditions. To develop knowledge about creationism and transformism, about C. Linnaeus, J.B. Lamarck and C. Darwin - representatives of these views. Chapter X. Development of evolutionary ideas
Slide 2
Diversity of living organisms (about 2 million species)
The fundamental questions of biology have been and remain questions related to the origin of the diversity of species on Earth and their amazing adaptability to their environment.
Slide 3
Creationism Creationists believe that living organisms were created by a higher power - the creator; transformists explain the appearance of diversity of species in a natural way, on the basis of natural laws. Creationists explain fitness by original expediency, species were created initially adapted, transformists believe that fitness appeared as a result of development, in the course of evolution.
Slide 4
The representative of the views of creationism was the Swedish scientist and naturalist Carl Linnaeus. He was a metaphysician, i.e. considered the phenomena and bodies of nature as once and for all data, unnamed. Linnaeus is called the “king of botanists”, “father of systematics”. He discovered 1.5 thousand species of plants, described about 10,000 species of plants, 5,000 species of animals. Reinforced the use of binary (double) nomenclature to designate species. Improved the botanical language - established a uniform botanical terminology. His classification was based on combining species into genera, genera into orders, orders into classes. Metaphysician Carl Linnaeus C. Linnaeus (1707-1778)
Slide 5
In 1735, his book “The System of Nature” was published, in which he classifies all plants into 24 classes based on the structural features of flowers: the number of stamens, unisexuality and bisexuality of flowers. During the author’s lifetime, this book was reprinted 12 times and had a great influence on the development of science in the 18th century. K. Linnaeus divided the fauna into 6 classes: mammals, birds, reptiles (amphibians and reptiles), fish, insects, worms. Almost all invertebrates were classified in the last class. His classification was the most complete for its time, but Linnaeus understood that a system created on the basis of several characteristics is an artificial system. He wrote: “An artificial system serves until a natural one is found.” But by natural system he understood the one that guided the creator when creating all life on Earth. Metaphysician Carl Linnaeus C. Linnaeus (1707-1778)
Slide 6
“There are as many species as the number of different forms the Almighty created at the beginning of the world,” said Linnaeus. But at the end of his life, Linnaeus recognized that sometimes species can be formed under the influence of the environment or as a result of crossing. Metaphysician Carl Linnaeus The rapid development of natural science in the second half of the 18th century was accompanied by an intensive accumulation of facts that did not fit into the framework of metaphysics and creationism; transformism was developing - a system of views about the variability and transformation of plant and animal forms under the influence of natural causes. C. Linnaeus (1707-1778)
Slide 7
The representative of the philosophy of transformism was the outstanding French naturalist Jean Baptiste Lamarck, who created the first theory of evolution. In 1809, his main work “Philosophy of Zoology” was published, in which Lamarck provides numerous evidence of the variability of species. Transformism. Evolutionary theory of J.B. Lamarck He believed that the first living organisms arose from inorganic nature through spontaneous generation, and ancient life was represented by simple forms, which as a result of evolution gave rise to more complex ones. The lowest, simplest forms arose relatively recently and have not yet reached the level of highly organized organisms. J.B. Lamarck (1744-1829)
Slide 8
Lamarck's classification of animals already includes 14 classes, which he divided into 6 gradations, or successive stages of complication of organization. The identification of gradations was based on the degree of complexity of the nervous and circulatory systems. Lamarck believed that classification should reflect “the order of nature itself,” its progressive development. Transformism. Evolutionary theory of J.B. Lamarck
Slide 9
This theory of gradual complication, the theory of “gradation,” is based on the influence of the external environment on organisms and the response of organisms to external influences, the direct adaptability of organisms to the environment. Lamarck formulates two laws according to which evolution occurs. Transformism. Evolutionary theory of J.B. Lamarck The first law can be called the law of variability: “In every animal that has not reached the limit of its development, more frequent and longer use of any organ gradually strengthens this organ, develops and enlarges it and gives it strength , commensurate with the duration of use, while constant disuse of one or another organ gradually weakens it, leads to decline, continuously reduces its abilities and, finally, causes its disappearance.” J.B. Lamarck (1744-1829)
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Is it possible to agree with this law? Lamarck overestimates the importance of exercise and non-exercise for evolution, so the characteristics acquired by the body are not transmitted to the next generation. Transformism. Evolutionary theory of J.B. Lamarck The second law can be called the law of heredity: “Everything that nature has forced to acquire or lose under the influence of the conditions in which their breed has been for a long time, and, therefore, under the influence of the predominance of the use or disuse of one or another part bodies - nature preserves all this through reproduction in new individuals that descend from the first, provided that the acquired changes are common to both sexes or to those individuals from which the new individuals descended.” J.B. Lamarck (1744-1829)
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Is it possible to agree with Lamarck's 2nd law? No, the position about the inheritance of characteristics acquired during life was erroneous: further research showed that only hereditary changes are decisive in evolution. There is a so-called Weismann barrier - changes in somatic cells cannot enter germ cells and cannot be inherited. Transformism. Evolutionary theory of J.B. Lamarck For example, A. Weisman cut off the tails of mice for twenty generations; non-use of the tails should have led to their shortening, but the tails of the twenty-first generation were the same length as the first. J.B. Lamarck (1744-1829)
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Transformism. Evolutionary theory of J.B. Lamarck And, finally, Lamarck explained fitness by the internal desire of organisms for improvement, for progressive development. Consequently, Lamarck considered the ability to respond expediently to the influence of conditions of existence as an innate property. Lamarck associates the origin of man with “four-armed monkeys” who switched to a terrestrial mode of existence. J.B. Lamarck (1744-1829)
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Transformism. Evolutionary theory of J.B. Lamarck And one more weak point in Lamarck’s theory. While justifying the origin of one species from another, he did not recognize species as really existing categories, as stages of evolution. “I consider the term “species” to be completely arbitrary, invented for the sake of convenience, to designate a group of individuals that are closely similar to each other... J.B. Lamarck (1744-1829)
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But this was the first holistic theory of evolution, in which Lamarck tried to determine the driving forces of evolution: 1 - the influence of the environment, which leads to the exercise or non-exercise of organs and the expedient change of organisms; 2 - inheritance of acquired characteristics. 3 - internal desire for self-improvement. Transformism. Evolutionary theory of J.B. Lamarck But the theory was not accepted. Not everyone recognized that gradation was influenced by the desire for self-improvement; that fitness arises as a result of expedient changes in response to environmental influences; the inheritance of acquired characteristics has not been confirmed by numerous observations and experiments. J.B. Lamarck (1744-1829)
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Tail docking in many dog breeds does not change their length. In addition, from the point of view of Lamarck’s theory, it is impossible to explain the appearance, for example, of the color of the shell of bird eggs and their shape, which is adaptive in nature, or the appearance of shells in mollusks, because his idea about the role of exercise and lack of exercise of organs is not applicable here. A dilemma has arisen between metaphysicians and transformists, which can be expressed in the following phrase: “Either species without evolution, or evolution without species.” Transformism. Evolutionary theory of J.B. Lamarck
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K. Linnaeus divided plants into 24 classes, based on .... The classification of K. Linnaeus was artificial because... Creationism, transformationism, metaphysical worldview…. How did the variety of species appear according to Linnaeus? How does K. Linnaeus explain the fitness of species? J.B. Lamarck in his book “Philosophy of Zoology” divided animals into 14 classes and arranged them into 6 levels according to degree…. 6 gradations of animals according to Lamarck... Its classification can be considered natural, since... The driving forces of evolution according to J.B. Lamarck are: …. How did the diversity of species appear according to Lamarck? As a result of exposure to the external environment in living organisms according to J. B. Lamarck.... How does J.B. Lamarck explain the fitness of species? The undoubted merit of J.B. Lamarck was .... His hypothesis was not accepted; not everyone recognized that... A. Weisman cut off the tails of mice for twenty generations, but... What is the Weismann barrier? Repetition:
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At the beginning of the 19th century. There was an intensive growth of industry in Western Europe, which gave a powerful impetus to the rapid development of science and technology. Extensive materials from overseas expeditions enriched the understanding of the diversity of living beings, and descriptions of systematic groups of organisms led to the idea of the possibility of their kinship. This was also evidenced by the striking similarity of chordate embryos, discovered during the study of the processes of individual development of animals. New data refuted the prevailing ideas about the immutability of living nature. To explain them scientifically, a brilliant mind was needed, capable of summarizing enormous material and connecting disparate facts with a coherent system of reasoning. Charles Darwin turned out to be such a scientist. Charles Darwin C. Darwin (1809-1882)
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Charles Darwin Charles Darwin was born on February 12, 1809 in the family of a doctor. Since childhood, I was interested in botany, zoology, and chemistry. He studied medicine at the University of Edinburgh for two years, then moved to the Faculty of Theology at Cambridge University and planned to become a priest. After graduating from university, Darwin went on a voyage around the world on the Beagle as a naturalist. The voyage lasted five years, from 1831 to 1836. In Time, when Chaos was burning, The suns exploded in a whirlwind and without measure, Other spheres burst out of spheres, When the surface of the seas settled on them And began to wash the land everywhere, Warmed by the sun, in grottoes, in the vastness The life of organisms originated in the sea. E. Darwin C. Darwin (1809-1882)
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