Development of ideas about the origin of life. The idea of ​​ancient and medieval philosophers about the soul and consciousness. Stages of development of psychology

Think!

Questions

1. What is biotechnology?

2. What problems does genetic engineering solve? What are the challenges associated with research in this area?

3. Why do you think the selection of microorganisms is currently becoming of paramount importance?

4. Give examples of the industrial production and use of waste products of microorganisms.

5. What organisms are called transgenic?

6. What is the advantage of cloning over traditional breeding methods?

1. What prospects do the use of transgenic animals offer in the development of the national economy?

2. Can modern humanity do without biotechnology?

Chapter 4. VIEW

4.1. Development of biology in the pre-Darwinian period. Work of C. Linnaeus

4.2. Evolutionary theory of J. B. Lamarck

4.3. Prerequisites for the emergence of the teachings of Charles Darwin

4.4. Evolutionary theory of Charles Darwin

4.5. Type: criteria and structure

4.6. Population as a structural unit of a species

4.7. Population as a unit of evolution

4.8. Factors of evolution

4.9. Natural selection is the main driving force of evolution

4.10. Adaptation of organisms to living conditions as a result of natural selection

4.11. Speciation as a result of evolution

4.12. Preservation of species diversity as the basis for sustainable development of the biosphere

4.13. Evidence for the evolution of the organic world

4.14. Development of ideas about the origin of life on Earth

4.15. Modern ideas about the origin of life

4.16. Development of life on Earth

4.17. Hypotheses of human origins

4.18. The position of man in the animal world

4.19. Human evolution

4.20. Human races

The world of living organisms has a number of common features that have always evoked a sense of surprise in humans and raised many questions. The first of these common features is the extraordinary complexity of the structure of organisms. The second is the obvious expediency of the structure; each species in nature is adapted to the conditions of its existence. And finally, the third pronounced feature is the huge diversity of existing species.

How did complex organisms arise? Under the influence of what forces were the features of their structure formed? What is the origin of the diversity of the organic world and how is it maintained? What place does a person occupy in this world and who are his ancestors? These and many other questions are answered by the theory of evolution, which is the theoretical basis of biology.

The term “evolution” (from Latin evolutio - deployment) was introduced into science in the 18th century. Swiss zoologist Charles Bonnet. In biology, evolution is understood as an irreversible process of historical change in living beings and their communities. Evolutionary teaching is the science of the causes, driving forces, mechanisms and general patterns of transformation of living beings over time. The theory of evolution occupies a special place in the study of life. It plays the role of a unifying theory, which forms the foundation for all biological science.

■Ancient and medieval ideas about the essence and development of life. People have tried to explain the origin of life and man since ancient times. Many religions and philosophical theories arose as attempts to resolve these global issues.

Ideas about the changeability of the surrounding world arose many thousands of years ago. In ancient China, the philosopher Confucius1 believed that life arose from a single source through divergence and branching. In the era of antiquity, ancient Greek philosophers were looking for that material principle that was the source and fundamental principle of life. Diogenes believed that all beings are similar to one original being and arose from it as a result of differentiation. Thales assumed that everyone was alive

1 Confucius (about 551 - 479 BC), Diogenes (about 400 - about 325 BC), Thales (about 625 - about 547 BC), Anaxagoras (about 500 - 428 BC), Democritus (ca. 470 or 460 BC - ?, died of old age), Pythagoras (VI century BC), Anaximander (ca. 610 - after 547 BC), Hippocrates (ca. 460-ca. 370 BC)

organisms originated from water, Anaxagoras argued that from air, and Democritus explained the origin of life by the process of its spontaneous generation from silt.

The research and philosophical theories of such outstanding scientists of antiquity as Pythagoras, Anaximander, and Hippocrates had a great influence on the development and formation of ideas about living nature.

The greatest of the ancient Greek scientists, Aristotle, possessing encyclopedic knowledge, laid the foundations for the development of biology and formulated the theory of the continuous and gradual development of living things from non-living matter. In his work “History of Animals,” Aristotle first developed a taxonomy of animals. He divided all animals into two large groups: animals with blood and bloodless ones. He, in turn, divided animals with blood into oviparous and viviparous. In another of his works, Aristotle first expressed the idea that nature is a continuous series of increasingly complex forms: from inanimate bodies to plants, from plants to animals and further to humans

With the advent of the Middle Ages, an idealistic worldview based on church dogmas spread in Europe. The Supreme Mind, or God, is proclaimed the creator of all living things. Considering nature from such positions, scientists believed that all living beings are the material embodiment of the Creator’s ideas, they are perfect, meet the purpose of their existence and are unchangeable over time. This metaphysical direction in the development of biology is called creationism (from the Latin creatio - creation, creation).

During this period, many classifications of plants and animals were created, but mostly they were of a formal nature and did not reflect the degree of relationship between organisms.

Interest in biology increased during the era of the Great Geographical Discoveries. America was discovered in 1492. Intensive trade and travel expanded knowledge about plants and animals. New plants were brought to Europe - potatoes, tomatoes, sunflowers, corn, cinnamon, tobacco and many others. Scientists have described many previously unseen animals and plants. There is an urgent need to create a unified scientific classification of living organisms.

■System of organic nature by K. Linnaeus. The outstanding Swedish naturalist Carl Linnaeus made a great contribution to the creation of the natural system. The scientist considered a species to be a real and elementary unit of living nature, having not only morphological, but also physiological criteria (for example, the non-crossing of different species). At the beginning of his scientific career, C. Linnaeus adhered to metaphysical views, so he believed that species and their number are unchanged. Having developed short and clear definitions of characteristics, the scientist described about 10 thousand species of plants and more than 4 thousand species of animals. At the age of 28, C. Linnaeus published his most famous work, “The System of Nature,” in which he described the basic principles of systematics - the science of classifying living organisms. He based his classification on the principle of hierarchy (subordination) of taxa (from the Greek taxis - arrangement in order), when several small taxa (species) are combined into a larger genus, genera are combined into orders, etc. The largest unit in the system Linnaeus was class. With the development of biology, additional categories (family, subclass, etc.) were added to the taxon system, but the principles of taxonomy laid down by Linnaeus have remained unchanged to this day. To designate species, the scientist introduced a binary (double) nomenclature, the first word of the name denoting the genus, the second - the species. In the 18th century The international scientific language was Latin, so Linnaeus gave names to species in Latin, which made his system universal and understandable throughout the world.

Carl Linnaeus built the first scientific system of living nature, which included all animals and all plants known at that time and was the most perfect for its time. For the first time, man was placed in the same group with monkeys. However, when distributing organisms into taxonomic groups, Linnaeus took into account a limited number of characteristics. For example, all animals were divided into 6 classes according to the structure of the respiratory and circulatory systems: worms, insects, fish, reptiles, birds and animals. Within classes, Linnaeus was based on smaller features, for example, he united birds by their beaks, and animals by the structure of their teeth.

Linnaeus chose the number of stamens as the main characteristic of flowering plants. This led to the fact that organisms that were far apart in terms of the degree of relatedness fell into one group. For example, lilac and willow were included in one of the 24 classes of plants, rice and tulip were included in another. Linnaeus identified all plants that do not have flowers in a separate class - secretagogues. However, along with algae, spores and gymnosperms, he also included fungi and lichens there. Realizing the artificiality of his system of nature, Linnaeus wrote: “An artificial system serves only until a natural one is created.”

Along with this, in the XVII-XIX centuries. In Europe, there was a different system of views on the variability of organisms, which was formed on the basis of the worldviews of ancient philosophers. Many prominent scientists of that time believed that organisms are capable of changing under the influence of the environment. However, scientists did not strive, and did not have the opportunity, to prove the evolutionary transformations of organisms. This direction in the development of biology is called transformism (from the Latin trani formo - I transform). Among the representatives of this trend are Erasmus Darwin (the grandfather of Charles Darwin), Robert Hooke, Johann Wolfgang Goethe, Denis Diderot, and in Russia - Afanasy Kaverznev and Karl Roulier.

Essay
According to the concept of modern natural science
On the topic: Charles Darwin's theory of evolution and the explanation of evolutionary processes based on genetics

Completed by: Stroeva N.E.
student gr. FMM-07

Checked by: Dyuldina E.V.
Professor of the Department of Chemistry and Physics,
Candidate of Technical Sciences

Magnitogorsk
2007
Content:

Introduction………………………………………………………… …………………………….…3
1. Historical background:

1.1 Ancient and medieval performances

about the essence and development of life……………………………………………………………....4

1.2 The teachings of K. Linnaeus……………………………………………………………. …....4

1.3 Teachings of J.B. Lamarck………………………………………………………. …..5

2.1 Prerequisites for the emergence of Darwin’s theory……………………............... .....7

2.2 Evolutionary theory of Charles Darwin……………………………………………………..…...8

3.1 Mendel’s laws…………………………………………...………………… ………......26

3.2 Hardy-Weinberg Law………………………………………………………… …………….…...27

3.3 Embryological evidence………………………………………….….29

Introduction

Historical reference

Ancient and medieval ideas about the essence and development of life

Bloodless Bloodless
(vertebrates) (invertebrates)

Viviparous Oviparous Soft-bodied Soft-shelled
tetrapods tetrapods (molluscs) (crayfish, crabs)
(mammals) (reptiles)
Insects Testate
Oviparous Oviparous legless, (molluscs)
with feathers living in the water
(birds) (fish)

In another of his works, Aristotle first expressed the idea that nature is a continuous series of increasingly complex forms: from inanimate bodies to plants, from plants to animals and further to humans.
With the advent of the Middle Ages, an idealistic worldview based on church dogmas spread in Europe. The Supreme Mind, or God, is proclaimed the creator of all living things. Considering nature from such positions, scientists believed that all living beings are the material embodiment of the Creator’s ideas, they are perfect, meet the purpose of their existence and are unchangeable over time. This metaphysical direction in the development of biology is called creationism(from lat. creation- creation, creation).

The teachings of K. Linnaeus
The outstanding Swedish naturalist Carl Linnaeus made a great contribution to the creation of the natural system. The scientist considered a species to be a real and elementary unit of living nature, having not only morphological, but also physiological criteria (for example, non-crossing of different species). At the beginning of his scientific career, C. Linnaeus adhered to metaphysical views, so he believed that species and their number are unchanged. He described about 10 thousand species of plants and more than 4 thousand species of animals. In 1735, Linnaeus published his most famous work, The System of Nature, in which he described the basic principles taxonomy– science of classification of living organisms. He based his taxonomy on the principle of hierarchy (subordination) of taxa (from the Greek . taxi- arrangement in order), when several small taxa (species) are combined into a larger genus, genera are combined into orders, etc. The largest unit in Linnaeus' system was the class. With the development of biology, additional categories were added to the taxon system (family, subclass, etc.), but the principles of taxonomy laid down by Linnaeus have remained unchanged to this day (Carl Linnaeus is the author first artificial taxonomy!). He also introduced binary nomenclature in Latin, which made his system universal and understandable throughout the world. The first word denoted the genus, the second the species (for example, white poplar - populous alba).
Carl Linnaeus built the first scientific system of living nature, which was the most advanced for its time. For the first time, man was placed in the same group with monkeys. He divided all animals into 6 classes according to the structure of the respiratory and circulatory systems: worms, insects, fish, reptiles, birds, animals. Linnaeus chose the number of stamens as the main characteristic of flowering plants. He got 24 classes: 1st class - single-stamen, 2nd class - bistamen, ..., 24th class - non-stamen. Linnaeus identified all plants that do not have flowers in a separate class - secretagogues. Along with algae, spores and gymnosperms, he also included fungi and lichens there. The taxonomy was artificial, because Carl Linnaeus classified according to 1-2 randomly selected characteristics. Realizing the artificiality of his systematics, he wrote: “An artificial system serves only until a natural one is created.”

Evolutionary theory of J.B. Lamarck

The creator of the first evolutionary theory was the outstanding French naturalist Jean Baptiste Lamarck. The scientist believed that the most general categories of phenomena, such as space, motion, matter and time, were created by God, and all other objects were formed by nature. Lamarck outlined the evolutionary theory in his two-volume work “Philosophy of Zoology” (1809). The scientist identified two main directions of the evolutionary process: the constant complication of the level of organization of living beings, which occurs over time (gradation, from the Latin gradation - gradual elevation) and an increase in diversity under the influence of environmental conditions.
Thus, Lamarck's evolutionary theory can be divided into two parts: the doctrine of the gradation of organisms and the doctrine of variability.
The doctrine of the gradation of organisms. Lamarck believed that the first organisms arose from inorganic nature through spontaneous generation. Their further self-development led to the complication of living beings, therefore the classification of organisms cannot be arbitrary, it must reflect the process of movement from lower to higher forms. The scientist divided all animals into 14 classes, which he distributed according to the degree of complexity of the organization, forming 6 steps - gradations.

VI (14. Mammals, 13. Birds, 12. Reptiles, 11. Fish)

V (10. Mollusks, 9. Barnacles)

IV (8. Ringlets, 7. Crustaceans)

III (6. Arachnids, 5. Insects)

II (4. Worms, 3. Radiant)

I (2. Polyps, 1. Ciliates)
In order to explain the mechanism of complication of living beings, Lamarck suggested the existence in all living organisms of a desire for improvement, which was originally inherent in them by God (the principle of self-improvement). Lamarck explained the simultaneous presence in nature of both simple and complex creatures by the constantly ongoing process of spontaneous generation of life.
The doctrine of variability. While improving, organisms are forced to adapt to environmental conditions. In order to explain how diversity arises at each step of the “ladder of beings,” Lamarck formulated two laws.
The law of exercise and non-exercise of organs: Constant use of an organ leads to its enhanced development, and disuse leads to weakening and disappearance. For example, the need to reach leaves on trees leads to the fact that the giraffe, trying to reach them, constantly stretches its neck, as a result of which it becomes long. An example of the disappearance of organs as a result of lack of exercise is the reduction of eyes in a mole.
Law of inheritance of acquired characteristics: under the influence of constant exercise and non-exercise, organs change, and the resulting changes are inherited. According to Lamarck, the giraffe's neck, which becomes elongated during life, will be passed on to the next generation, which will be born with a more elongated neck. The discovery in the 20th century of the material basis of heredity—DNA—finally refuted the possibility of inheriting acquired characteristics.
The meaning of Lamarck's theory. Lamarck's teaching became the first holistic evolutionary theory. The scientist determined the prerequisites for evolution (variability and heredity) and indicated the direction of evolution (increasing complexity of organization). However, having correctly assessed the development of nature from simple to complex, Lamarck was unable to reveal the causes of evolution. The created theory could not explain many existing phenomena, such as the inheritance of unfavorable characteristics (for example, vestigial organs), the appearance of mimicry or protective coloration.
Lamarck's evolutionary ideas did not find support among his contemporaries and were criticized by many scientists.

Charles Darwin's theory of evolution and explanation of evolutionary processes based on genetics

I. Prerequisites for the emergence of the teachings of Charles Darwin
Natural science background. By the middle of the 19th century. Many new discoveries have been made in natural science. Immanuel Kant created a theory about the origin of cosmic bodies naturally, and not as a result of divine creation. The French scientist Pierre Simon Laplace in his work “Exposition of the World System” mathematically substantiated the theory of I. Kant. In 1824, chemists synthesized organic substances for the first time, proving that their formation occurs without the participation of “higher powers.” Jens Berzelius showed the unity of the elemental composition of living and inanimate nature. In 1839, T. Schwann and M. Schleiden created the cell theory, which postulated that all living organisms are composed of cells, the general features of which are the same in all plants and animals. This was significant evidence of the unity of origin of the living world.
K. M. Baer showed that the development of all organisms begins with the egg. At the same time, all vertebrates exhibit common features of embryonic development: in the early stages, surprising similarities are found in the structure of embryos belonging to different classes.
Arose paleontology(from Greek palaios- ancient, ontos- existing, logos – word, doctrine) - the science of extinct plants and animals preserved in the form of fossil remains, imprints and traces of their life activity; about their change in the process of development of life on Earth.
Studying the structure of vertebrates, J. Cuvier established that all animal organs are parts of one integral system. The structure of each organ corresponds to the principle of the structure of the whole organism, and a change in one part of the body must cause a change in one part of the body must cause a change in other parts. Cuvier called the correspondence of the structure of organs to each other principle of correlation.
While studying taxonomy, J. Cuvier studied the structural types of animals. Comparing the anatomical structure of various living organisms, he discovered their deep similarity despite their external diversity. Such similarities indicate their possible relationship and common origin.
The English geologist Charles Lyell refuted the catastrophe theory of J. Cuvier and proved that the Earth's surface changes gradually under the influence of the most common natural factors: wind, rain, surf, volcanic eruptions, etc.
Facts and discoveries in various fields of natural science contradicted the theory of the divine origin and immutability of the existence of nature. But it was not only in the scientific community that the prerequisites for the emergence of a new evolutionary theory were maturing.
Socio-economic prerequisites. The development of capitalism and the sharp growth of urban populations in developed countries required rapid development of agriculture. In the most advanced country of that time, England, industrial livestock and crop production successfully developed. In a short period of time, new breeds of sheep and pigs were created, and high-yielding varieties of cultivated plants were bred; selection methods were developed that made it possible to quickly “change animal breeds and plant varieties in the right direction; the results of this work contradicted the dogmas of the church about the immutability of species.
The expansion of trade, establishing connections with other countries, and the development of new territories made it possible to collect huge collections, which provided additional material for rethinking the laws of natural development.
Back at the end of the 18th century. The famous economist Adam Smith created the doctrine that the elimination of unadapted individuals occurs through the process of free competition.
The work of economist Thomas Malthus, “Essay on the Law of Population,” had a huge influence on the development of evolutionary ideas in society. Having first introduced the expression “struggle for existence,” Malthus explained that man, like all other organisms, is characterized by the desire for limitless reproduction. However, resource scarcity limits human growth, leading to poverty, hunger and disease.
By the middle of the 19th century. The views of creationists have already sharply contradicted the entire course of development of science and practice. Many scientists supported propagated the ideas of evolutionary development. The ideas of evolution also found their supporters in Russia.
In the 18th century developed materialist ideas about the unity and development of the world by the democratic philosopher Alexander Nikolaevich Radishchev. Studying domestic and wild animals, Afanasy Kaverznev explained the diversity of the animal world by the existence of variability.
Alexander Ivanovich Herzen suggested that the mental activity of people is not a divine sign, but is a logical result of the gradual development of nervous activity in animals.
The works of the Russian naturalist Karl Frantsevich Roulier laid the foundations of evolutionary paleontology. The scientist put forward the position that changes in animals are caused by two reasons: the characteristics of the organism itself (heredity) and the influence of external factors.
There was an urgent need to create an evolutionary theory that would answer all the questions accumulated in society and explain what mechanisms underlie the development of nature from simple to complex; why some species appear and others die out; what causes the expediency of the emerging adaptations.

II Evolutionary theory of Charles Darwin
The text below is a synthetic theory of Darwin, since it is orthodox to consider Darwinism of the 19th century, which partially does not correspond to the knowledge of the 21st century. In all literature, Darwin's synthetic theory is mainly presented, with adjustments for time and knowledge acquired later.

Population as a structural unit of a species
A species is a complex system of intraspecific groups that develops during the process of evolution under certain conditions. The most common intraspecific structural unit is population. Within a population, smaller units can be distinguished: packs, families, prides, which are less stable and can easily disappear, merge and form anew. Within the range of the species, populations are usually unevenly distributed. This is due to the conditions of existence: where they are most favorable, the number of populations and their numbers are higher. At the boundaries of the species range, populations are usually small.
Each population has a specific structure and is characterized by specific parameters.
Population area. For different species, population ranges can vary significantly in extent. Populations of large animal species have a larger range than populations of small and sedentary animals. An example of large continuous populations are cereals growing on plains and covering areas tens and hundreds of kilometers wide. The population area is not a constant value; it can expand or contract, for example, as a result of changes in the number of individuals.
Population size and dynamics. The population size can change over time as a result of changes in environmental conditions, fluctuations in mortality and birth rates, and due to the migration of individuals.
Measure total number populations can be quite complex, so they often use an indicator such as population density- the number of individuals living in a unit area or concentrated in a unit volume (for example, for aquatic animals). Population density varies greatly between seasons and years. Such fluctuations occur most sharply in small organisms with short life cycles. For example, the massive proliferation of green algae in the summer causes water blooms. The numbers and density of populations are more stable in large organisms (for example, woody plants).
The demographic indicators of a population are birth rate and death rate.
Fertility is the number of new individuals that appeared in the population as a result of reproduction per unit of time. Mortality- the number of individuals that died over a certain period of time. These two indicators have a significant impact on the number of individuals in the population and depend not only on the biological characteristics of the species, but also on many external reasons. Overpopulation has a strong impact on the birth rate. As population density increases, animals begin to experience stress, which leads to the release of certain hormones. As a result, the frequency of miscarriages increases, animals lose the ability to mate, their reproductive behavior changes, aggressiveness increases, care for offspring weakens and, as a result, the birth rate decreases.
When describing processes occurring in populations, it is often important to know not the total number of individuals, but the number of organisms capable of reproduction. To indicate the number of breeding individuals, the concept is used effective strength.
Typically, the population size remains around the average level from year to year. However, in certain favorable years for the population, its numbers can increase sharply. Outbreaks of mass reproduction of gypsy moths, locusts and many other species are known. Due to the high harvest of food, the population size of hares, squirrels, and lemmings increases. There is a sharp increase in the number of individuals of species entering new regions where they have no natural enemies (rabbits in Australia, muskrats in Europe). A population can very quickly reach its maximum possible size if the species that limit its growth disappear. This happened to pest populations in China after sparrows were eradicated there.
If the population density reaches either too high or too low values, certain mechanisms are activated that restore this value to the optimal number of individuals for this habitat. This ability of populations to self-sustain is called regulation of numbers.
There are many mechanisms for regulating numbers, so catastrophic fluctuations rarely occur in nature, which undermine environmental resources and lead to the death of a population.
Population composition. Each population consists of individuals that differ in sex and age.
Age structure- the ratio of individuals of different ages in a population. This indicator depends on the life expectancy of individuals, the time they reach sexual maturity, the intensity of reproduction, mortality, etc. The age structure of the population can change under the influence of external factors, since they control both fertility and mortality. The wider the age composition of a population, the more resistant it is to external factors. Knowing the age composition of a population allows us to predict its development several years in advance.
Populations consisting of many successive generations have a complex age structure. In other populations, the age structure can be very simple, for example in annual plants, where all individuals are the same age.
Sexual structure- the ratio of individuals of different sexes. In most populations, in accordance with genetic patterns, the sex ratio is 1:1. However, as a result of different survival rates of male and female individuals at different stages of individual development, this ratio can change significantly.
The sexual structure of populations is not determined in hermaphrodite animals (for example, earthworms). In some species that are capable of reproducing without fertilization (daphnia, aphids, etc.), populations at certain stages of the life cycle are represented only by females. In such populations, the efficiency of reproduction reaches maximum values.
Being an integral dynamic structure existing in time and space, population is an elementary biological part of a species capable of evolutionary changes.

Population as a unit of evolution
Elementary unit of evolution. The process of evolution takes place over thousands and millions of years, so it cannot affect an individual. Although every organism undergoes ontogenetic changes during its life, the evolutionary process does not occur at the level of a single organism.
The elementary unit of evolution must satisfy certain requirements, namely:

act in time and space as a certain unity;
be able to form a reserve of hereditary variability and hereditarily change over time;
actually exist in certain natural conditions for a long time, commensurate with the timing of speciation.

Factors of evolution
Hereditary variability. The factor that ensures the emergence of new genetic material in a population and new combinations of this material is hereditary, or genotypic, variability. There are two forms of such variability: combinative and mutational.
Mutations occur with a certain frequency in all living organisms. Different genes change with approximately equal probability, so mutational changes affect all characteristics and properties of organisms, including those affecting viability and reproduction. Mutations do not arise in a directional manner and do not have an adaptive significance, that is, they cause the very vague hereditary variability that Darwin spoke about.
Dominant mutations (IN) appear in the first generation, and their further fate depends on their significance. Harmful mutations will lead to the death of the organism or to a decrease in its viability. Even if the individual does not die, its probability of leaving offspring will be significantly reduced, i.e. natural selection will quite quickly remove carriers of such mutations from the population. Mutations that are neutral and useful under given natural conditions will persist in subsequent generations.
However, recessive mutations occur much more often (b), which can be passed on from generation to generation in a hidden form for a long time. Carriage of recessive mutations (heterozygous state - Bb) in most cases, it does not affect the viability of the individual and, therefore, selection will not act on such individuals. Over time, when a sufficient number of heterozygous individuals carrying such a mutation accumulate in the population, these mutations can become homozygous (bb). The further fate of these mutations depends on the degree of their significance for organisms. Useful traits will be preserved in the population, and those with harmful ones will be removed through natural selection.
The degree of “usefulness” of a mutation is determined by the environmental conditions in which a particular population lives. When these conditions change, the significance of mutations may also change: what is harmful when some environmental factors are combined may be useful in another situation.
The number of mutations that occur is expressed as the percentage of gametes of one generation containing any newly occurring mutation. In well-studied species of the fruit fly Drosophila, 25% of all germ cells contain one mutation or another, in mice and rats - about 10%. As can be seen from these numbers, the amount of elementary evolutionary material is quite large.
The occurrence of mutations - elementary units of hereditary variability leads to an increase in the genetic diversity of the population. This diversity is enhanced by the creation of random genetic combinations through crossbreeding. Recessive mutations in the heterozygous state form a hidden variability reserve, which can be used when changing the conditions of existence of a population.
The mutation process is only a supplier of elementary evolutionary material. Its pressure on natural populations always exists and maintains the genetic diversity of these populations at a high level. At the same time, due to its random nature, the mutation process is not capable of exerting a guiding influence on the process of evolution.
Population waves. Under natural conditions, the population size is constantly changing. Such periodic and non-periodic fluctuations in the number of individuals making up a population are called population waves. As a result of some random reasons, such as a lack of food, epidemics or the influence of predators, the number of individuals in the population can sharply decrease, i.e. carriers of certain genotypes will die. In a small population, some individuals, regardless of their genotype, due to random reasons, may or may not leave offspring, which will lead to a change in the frequency of occurrence of certain alleles in the population. In this case, some alleles may completely disappear from the population. The process of random, non-directional change in allele frequencies in a population is called genetic drift. As a result, the gene pool of the remaining population will differ significantly from the gene pool of the original population. This phenomenon, in which a population goes through a period of low numbers, is called bottleneck effect. If in the future the influence of unfavorable factors disappears and the population restores its numbers to its original level, its genotypic structure will reflect the genotypes of those individuals that went through the bottleneck. As a result of random genetic drift, genetically homogeneous populations living in similar conditions can gradually lose their original similarity. Thus, fluctuations in numbers (population waves) cause changes in the genetic structure of the population.
So, hereditary variability and population waves belong to the first group of factors that cause random changes in the gene pool of a population. However, in order for the population to develop independently in the future on the basis of its own gene pool, it must be isolated from other similar populations.
Insulation. Insulation - this is the limitation or complete absence of crossings of individuals from different populations. As long as there is gene flow between populations, they cannot accumulate significant genetic differences. Isolation leads to the cessation of the exchange of hereditary information and turns the population into an independent genetic system.
A distinction is made between spatial and environmental isolation.
Spatial isolation is associated with the existence of geographical barriers between populations, such as mountain ranges, deserts, reservoirs, etc.
At environmental insulation Crossing between organisms of different populations becomes impossible if individuals of these groups are separated by environmental obstacles within the same landscape. For example, the inhabitants of one swamp have little chance of meeting the inhabitants of another swamp during the breeding season, etc.
The evolutionary significance of various forms of isolation lies in the fact that they consolidate and strengthen genetic differences between populations, and therefore create the preconditions for the further transformation of these populations into separate species.
So, such evolutionary factors as hereditary variability, population waves and isolation change the gene pool of populations and ensure their independent existence, creating conditions for the action of the main evolutionary factor - natural selection.

Natural selection is the main driving force of evolution
Natural selection - This is the preferential survival and reproduction of the most adapted individuals of each species and the death of less adapted organisms. The principle of natural selection, which was first put forward by Charles Darwin, is fundamental in the theory of evolution. It is natural selection that is the third necessary factor that directs the evolutionary process and ensures the consolidation of certain changes in the population.
Natural selection is based on genetic diversity And excess number of individuals in the population. Genetic diversity creates material for selection, and an excess number of individuals leads to competition and, as a consequence, to the struggle for existence.
etc.................

History of ideas about the development of life on Earth

The first attempt to systematize and generalize the accumulated knowledge about plants and animals and their life activity was made by Aristotle (IV century BC), but long before him, in the literary monuments of various peoples of antiquity, a lot of interesting information was presented about the organization of living nature, mainly related to agronomy, animal husbandry and medicine;1 biological knowledge itself goes back to ancient times and is based on the direct practical activities of people. From the rock paintings of Cro-Magnon man (13 thousand years BC), it can be established that already at that time people could clearly distinguish a large number of animals that served as the object of their hunt.

Ancient and medieval ideas about the essence and development of life

In Ancient Greece in the VIII-VI centuries. BC e. in the depths of the holistic philosophy of nature, the first rudiments of ancient science arose. The founders of Greek philosophy Thales, Anaximander, Anaximenes and Heraclitus were looking for a material source from which the world arose due to natural self-development. For Thales, this first principle was water. Living beings, according to the teachings of Anaximander, are formed from indefinite matter - “aleurone” according to the same laws as objects of inanimate nature. The third Ionian philosopher Anaximenes considered the material origin of the world to be air, from which everything arises and into which everything returns. He also identified the human soul with air.

The greatest of the ancient Greek philosophers was Heraclitus of Ephesus. His teaching does not contain special provisions about living nature, but it was of great importance both for the development of all natural science and for the formation of ideas about living matter. Heraclitus was the first to introduce into philosophy and natural science a clear idea of ​​constant change. The scientist considered fire to be the origin of the world; he taught that every change is the result of struggle: “Everything arises through struggle and out of necessity.”

The development of ideas about living nature was greatly influenced by the research and speculative concepts of other scientists of antiquity: Pythagoras, Empedocles, Democritus, Hippocrates and many others (see Chapter 2).

In the ancient world, information about living nature that was numerous for that time was collected. Aristotle was engaged in a systematic study of animals, describing more than 500 species of animals and placing them in a certain order: from simple to increasingly complex. The sequence of natural bodies outlined by Aristotle begins with inorganic bodies and goes through plants to attached animals - sponges and ascidians, and then to freely moving marine organisms. Aristotle and his students also studied the structure of plants.

In all bodies of nature, Aristotle distinguished two sides: matter, which has various possibilities, and form - the soul, under the influence of which this possibility of matter is realized. He distinguished three types of soul: vegetable, or nourishing, inherent in plants and animals; feeling, characteristic of animals, and reason, which, in addition to the first two, is endowed with man.

Throughout the Middle Ages, the works of Aristotle were the basis of ideas about living nature.

With the establishment of the Christian Church in Europe, the official point of view, based on biblical texts, spreads: all living things are created by God and remain unchanged. This direction in the development of biology in the Middle Ages is called creationism (from the Latin creatio - creation, creation). A characteristic feature of this period is the description of existing species of plants and animals, attempts to classify them, which for the most part were of a purely formal (alphabetical) or applied nature. Many systems of classification of animals and plants were created, in which individual characteristics were arbitrarily taken as a basis.

Interest in biology increased during the era of the Great Geographical Discoveries (15th century) and the development of commercial production. Intensive trade and the discovery of new lands expanded information about animals and plants. New plants were brought from India and America to Europe - cinnamon, cloves, potatoes, corn, tobacco. Botanists and zoologists described many new, previously unseen plants and animals. For practical purposes, they indicated what beneficial or harmful properties these organisms had.

The formation of psychology as a science was closely connected with the development of philosophy and the natural sciences, in the depths of which its formation took place. The first ideas about the psyche developed in primitive society. Even in ancient times, people drew attention to the fact that there are real phenomena, material (objects, nature, people) and non-material (images of people and objects, memories, experiences) - mysterious, but existing independently, regardless of the surrounding world. This is how the idea of ​​body and soul, of matter and psyche as independent principles arose. These ideas later became the basis of fundamentally opposing philosophical directions, between which there was a constant struggle of views and approaches. Ancient thinkers made the first attempts to find answers to the questions: what is the soul? What are its functions and properties? How does it relate to the body?

Stage 1. The greatest philosopher of antiquity Democritus(V-IV centuries BC) claims that the soul also consists of atoms, and with the death of the body the soul also dies. The soul is the driving principle, it is material. A different idea of ​​the essence of the soul develops Plato(428-348 BC). Plato argues that everything is based on ideas that exist on their own. Ideas form their own world; the world of matter opposes it. Between them, the world soul acts as an intermediary. According to Plato, a person does not so much know as remember what the soul already knew. The soul is immortal, Plato believed. The first work devoted to the soul was created by Aristotle (384-322 BC). His treatise “On the Soul” is considered the first psychological work. This is how the historically first stage of the formation of psychology as a science of the soul took place. Stage 2. By the beginning of the 17th century, when mechanics and some areas of mathematics and natural sciences had already received significant development, the methodological prerequisites for understanding psychology as an independent branch of knowledge were laid. The psychology of the soul is being replaced by the psychology of consciousness. The soul begins to be understood as consciousness, the activity of which is directly related to the work of the brain. In contrast to the psychology of the soul, which is based on simple reasoning, the psychology of consciousness considers the main sources of knowledge self-observation of your inner world. This specific cognition is called the method introspection(“looking inside”) The formation of psychological views during this period is associated with the activities of a number of scientists: Rene Descartes (1595-1650), B. Spinoza (1632-1677), D. Locke (1632-1704) etc. The further development of sciences, especially natural sciences, within the framework of which objective research methods were developed, increasingly raised the question of the possibility of objective psychological research. The research of physiologists and naturalists of the first half of the 19th century played a special role in this regard. Played a big role in this regard evolutionary doctrine of G. Darwin(1809-1882). There are a number of fundamental studies devoted to the general patterns of sensitivity development and specifically to the work of various sense organs (I. Muller, E. Weber, G. Helmholtz, etc.). Of particular importance for the development of experimental psychology were the works of Weber, devoted to the question of the relationship between the increase in irritation And sensation. These studies were then continued, generalized and subjected to mathematical processing G. Fechner. Thus the foundations of experimental psychophysical research were laid. The experiment begins to very quickly take root in the study of central psychological problems. In 1879, the first psychological experimental laboratory was opened in Germany (W. Wund) and in Russia (V. Bekhterev), experimental work began to rapidly expand, and psychology became an independent experimental science. The introduction of experimentation into psychology made it possible to pose the question of methods of psychological research in a new way and to put forward new requirements and criteria for being scientific. During this period, such psychological concepts as “ soul", "conscious and unconscious", some scientific concepts arise and, nevertheless, this period is often called the period open crisis. There were many reasons that led psychology to a crisis: Many theoretical propositions were not sufficiently well substantiated and confirmed experimentally. Stage 3. The crisis led to the collapse of established psychological views. It was during this period that new directions began to take shape, which played an important role in the development of psychological science. The three most famous of them are: behaviorism, psychoanalysis, gestalt psychology. Stage 4. Psychology is a science that studies facts, patterns and mechanisms of the psyche.

Biology methods

The main methods in biology are:

· Descriptive

Comparative

· Experimental

· Historical

The meaning of biology great for medicine. Biology is the theoretical basis of medicine. The ancient Greek physician Hippocrates believed that “it is necessary that every physician understand nature.” All theoretical and practical medical sciences use general biological generalizations. Theoretical research conducted in various fields of biology allows the data obtained to be used in the practical activities of medical workers.

Biosocial nature of man.

Humans have a unique place on the planet among other creatures. This is due to their acquisition in the process of anthropogenesis of a special quality - social essence. This means that it is no longer biological mechanisms, but primarily the social structure, production, and labor that ensure survival, worldwide and even cosmic settlement, and the well-being of humanity. Sociality, however, does not contrast people with the rest of living nature. The acquisition of this quality only indicates that from now on the historical development of representatives of the species Homo Sapiens, i.e. humanity, is subject to the laws of social, not biological development.

The development of life in one of its branches led to the emergence of modern man, who combines the biological and the social. These relationships cannot be represented as a simple combination or subordination of one to the other. Biological processes occur in the human body; they play a fundamental role in determining the most important aspects of life support and development. At the same time, these processes in human populations do not produce results that are natural and obligatory for the populations of other representatives of the world of living beings.

In the conditions of modern energy and technical equipment, the impact of humanity on the biosphere is such that it is no longer possible, even from a medical point of view, for people to continue to ignore their own biology, their biological inheritance.

The importance of biology as a basic discipline in the training of a doctor.

The importance of biology for medicine is great. Biology is the theoretical basis of medicine. The ancient Greek physician Hippocrates believed that “it is necessary that every physician understand nature.” All theoretical and practical medical sciences use general biological generalizations.

Theoretical research conducted in various fields of biology allows the data obtained to be used in the practical activities of medical workers. The dependence of people's health on the quality of the environment and lifestyle is no longer in doubt either among practicing doctors or health care organizers. A natural consequence of this is the currently observed greening of medicine.

Development of ideas about the essence of life. Definition of life from the perspective of a systems approach.

Development of ideas about the essence of life. Definition of life.

Many scientists and philosophers have given definitions to the concept of “life,” but there is no strict and clear definition of the concept of “life,” since the amazing diversity of life creates great difficulties for its unambiguous and comprehensive definition as a special natural phenomenon. Many definitions of life, proposed by outstanding thinkers and scientists, indicate the leading properties that qualitatively distinguish living from non-living. Definitions of life were also given based on the substrate, which is the bearer of the properties of living things.

Life can be defined as the existence of complexes of nucleic acids and proteins in a certain cellular environment, its essence lies in maintaining sufficient constancy of this structure (nucleic acid + protein). Flows of energy, information, and matter pass through living systems. Life is a higher form of existence of matter compared to the physical and chemical.

Basic properties of living things

· Chemical composition.

· Structural organization.

· Metabolism and energy.

· Self-regulation.

· Integrity (continuity) and discreteness (discontinuity).

· Self-reproduction (reproduction).

· Heredity and variability.

· Growth and development.

· Irritability and excitability.

Biological (living) systems are a special stage of development and a form of movement of matter. General theory of systems, theory of biological systems, significance of the works of A.A., Bogdanov, P.K. Anokhina, L. von Bertalanffy in their development.

4. Almost everything biological systems belong to the open type.

One of the negative manifestations of human activity in nature is associated with disruption of connections in ecosystems, which can lead to the destruction of ecosystems or their transition to another state. Energy processes in biological systems obey the first and second laws of thermodynamics. The entropy value becomes maximum as the biological system reaches a state of equilibrium. At the same time, as they grow and develop, living organisms become more complex and are characterized by low entropy.