What prevents the exchange of genetic information between populations. The main factors of evolution

Test in biology "Evolution of the living world on Earth"

1. Item namebiology

2. Teacher Chernousova S.A.

3.Date. 9a - 10/18/2016, 9b - 10/14/2016

4.Goals of control: check mastery level educational material students in the section "evolution of the living world on Earth"

5. evaluation criteria:

Ioption

IIoption

1-4,2-1,3-4,4-1,5-1,6-2,7-1,8-1,9-1,10-4

1-2,2-3,3-1,4-4,5-4,6-3,7-1,8-4,9-4,10-2

2,4,5

1,2,5

12121

211212

1. There is a manifestation of modification (non-hereditary, certain, phenotypic) variability;

2. The manifestation of this feature is determined by seasonal changes in temperature and day length

1. Form of fitness - protective coloring.

2. Any adaptation is relative, i.e. fitness arises due to natural selection and relative to the environment in which a living organism lives

0-8b "2"

9-11b "3"

12-14b "4"

15-17b "5"

1 option

A1. What is the guiding factor of evolution?

1) heredity 2) variability 3) struggle for existence 4) natural selection

A2. What is the most accurate way to determine species?

1) genetic 2) geographical 3) morphological 4) physiological

A3. What hinders the exchange genetic information between populations?

A4. Which of the elementary factors of evolution gives rise to new genes?

1) mutational variability 3) gene drift

2) population waves 4) isolation

A5. Under gradually changing environmental conditions, natural selection acts

A6. Which of the scientists considered the striving for perfection of organisms as the driving force of evolution and claimed the inheritance of acquired traits?

A7. An example of an intraspecific struggle for existence is the relationship:

1) black cockroaches among themselves 3) black cockroaches with pesticides

2) black and red cockroaches 4) black cockroaches and black rats

A8. The change of fur, hibernation in mammals, well-developed root systems in plants are examples of...

1) fight adverse conditions environment 3) intraspecific mutual assistance

2) intraspecific struggle for existence 4) interspecific struggle

A9. Select a reason for geographic isolation.

1) migration of a group of individuals outside the range of the original species

2) the occurrence in a group of individuals of a biochemical difference in gametes

3) the emergence in a group of individuals of features in the structure

4) a change in the timing of reproduction in a group of individuals

A10. Under relatively constant environmental conditions, acts ... natural. selection

1) moving 2) disruptive 3) tearing 4) stabilizing

IN 1. Which of the following factors lead to a decrease in the number of mouse-like rodents in a coniferous forest?

1) reduction in the number of birds of prey and mammals

2) cutting down coniferous trees

3) harvest of spruce cones after a warm dry summer

4) increase in activity of predators

5) outbreak of epidemics

6) deep snow cover in winter

IN 2. Establish a correspondence between the forms of the struggle for existence and their characteristics

CharacteristicsForms of struggle for existence

a) competition for food, shelter, females 1) intraspecific

c) very tough and sharp fight

d) leads to the development of mutual adaptations

e) contributes to the prosperity of the species

C1. The density of the coat of mammals of the middle band changes during the year, molting occurs. Explain what type of variability is observed in mammals and what determines the manifestation of this trait.

Biology test "Evolutionary doctrine"

IIoption

A.1 What is the name of the complex of various relationships between organisms and factors of inanimate and living nature?

1) natural selection 3) fitness

2) struggle for existence 4) variability

A2. What phenomenon leads to a change in the gene pool of a population?

1) reproduction 2) isolation 3) natural selection 4) modification variability

A3. The reduction of leaves and the formation of long roots in plants is an example:

1) fight against adverse environmental conditions 3) intraspecific mutual assistance

2) intraspecific struggle for existence 4) interspecific struggle for existence

A4. What evolutionary factor contributes to the emergence of barriers to free interbreeding of individuals?

1) waves of life 2) natural selection 3) modifications 4) isolation

A5. To preserve mutations leading to less variability in the average value of the trait, natural selection is directed ...

1) moving 2) disruptive 3) tearing 4) stabilizing

A6. In winter, animals change color, coat density, hibernate. This is an example

1) fight against adverse environmental conditions 3) intraspecific mutual assistance

2) intraspecific struggle for existence 4) interspecific struggle for existence

A7. indicate the animal for which the struggle for existence is most intense and accompanied by a greater loss of offspring.

1) roundworm 2) rat 3) partridge 4) elephant

A8. What is natural selection?

1) complex relationship between living and inanimate nature

2) the process of formation of new populations and species

3) the process of population growth

4) the process of preserving individuals with beneficial hereditary changes

A9. The emergence of industrial melanism in insects is facilitated by ... natural selection

1) moving 2) disruptive 3) tearing 4) stabilizing

A10. Which of the scientists considered the striving for perfection of organisms as the driving force of evolution and claimed the inheritance of acquired traits?

1) Carl Linnaeus 2) Jean-Baptiste Lamarck 3) Charles Darwin 4) A.N.Severtsov

IN 1. What are the main forms of natural selection?

1) stabilizing 2) driving 3) methodical

4) individual 5) tearing 6) artificial

IN 2. Establish a correspondence between types of selection and their examples

ExamplesSelection types

a) the endurance of dogs to frost 1) artificial selection

b) attachment of dogs to humans 2) natural selection

c) high egg production in domestic chickens

d) protective coloration of the white hare

e) breed of rabbit with pure white wool

e) horse hooves

C. In the Far North, many animals are painted white ( polar bear, white partridge). Indicate the form of adaptability of animals and its nature.

In populations of one species, the action of the prerequisites of evolution leads to the emergence of a diversity of genotypes and phenotypes. This is the basis for the struggle for existence and natural selection. There are two forms of isolation: geographical and biological.

Geographical (spatial) isolation is the isolation of a certain population from another population of the same species by some barriers that are difficult to overcome. The first reason is large territorial gaps between populations in species with mosaic ranges. The occurrence of these gaps may be associated with glaciers, human activities, or the dispersal of populations outside the original range. The second reason is the geographical barriers separating the populations (rivers, mountains, gorges, forest areas, meadows, swamps). Geographical isolation prevents individuals from separated populations from interbreeding freely due to the impossibility of their meeting due to a geographical barrier.

Biological isolation is due to biological differences between individuals in populations. Depending on the nature of the differences, four types of biological isolation are distinguished: ecological, ethological, morphophysiological and genetic.

Ecological isolation is caused by a shift in reproductive periods (the timing of flowering, nesting, mating, spawning) or different breeding sites, which prevents free crossing of individuals in populations.
Ethological isolation is due to the behavior of individuals during the mating season. At first glance, insignificant differences in courtship rituals in the exchange of visual, sound, chemical signals can lead to the termination of this ritual and the restriction of mating.

Morphophysiological isolation is due to differences in the size of individuals or in the structure of the reproductive systems (some species of pulmonary mollusks, rodents). It does not interfere with the meeting of the sexes, but prevents the crossing of individuals due to the impossibility of fertilization.

Genetic isolation is due to large chromosomal and genomic rearrangements that cause differences in the number, shape, and composition of chromosomes. It does not interfere with the meeting of the sexes and fertilization. But it excludes the exchange of genetic information between populations due to the death of zygotes after fertilization, varying degrees of sterility of hybrids and their reduced viability.

The effect of any form of isolation on evolutionary material is not directed, but is a necessary condition for enhancing genetic differences between populations. An important characteristic of isolation is its duration, due to which the action of multidirectional natural selection leads to a divergence of the signs of populations - divergence. As a result, populations turn into varieties, or races. Maintaining isolation leads to increased differences between varieties, and they turn into subspecies. If increasing differences between subspecies prevents them from interbreeding, then they have become genetically closed systems. There was a reproductive isolation between them. Subspecies evolved into new species.

Thus, the factors of speciation are:
1. prerequisites for evolution: mutational and combinative variability, population waves, gene flow and drift, isolation;
2. driving forces of evolution: struggle for existence, natural selection

Based on a large number of examples, Darwin also notes that each pair of organisms can give a significant number of offspring (animals lay many eggs, eggs, many seeds and spores ripen in plants), but only a small part of them survive. Most individuals die before reaching not only sexual maturity, but also adulthood. The causes of death are unfavorable environmental conditions: lack of food, enemies, illness or heat, drought, frost, etc. On this basis, Darwin comes to the conclusion that in nature there is a continuous struggle for existence(Fig. 46). It is carried out both between individuals of different species ( interspecies struggle for existence and between individuals of the same species (intraspecific struggle for existence). Another manifestation of the struggle for existence is

struggle with inanimate nature.

As a result of the struggle for existence, some variations in traits in one individual give it a survival advantage over other individuals of the same species with other variations in inherited traits. Some individuals with unfavorable variations die. Ch. Darwin called this process natural selection. Inherited traits that increase the likelihood of survival and reproduction of a given organism, transmitted from parents to offspring, will occur more and more often in subsequent generations (since there is a geometric progression of reproduction). As a result, over a certain period of time, there are many such individuals with new characters, and they turn out to be so different from the organisms of the original species that they already represent individuals of a new species. Darwin argued that natural selection is the general way for the formation of new species.

Darwin puts forward an important new hypothesis about the presence in nature of natural selection, which is carried out by the influences of external conditions among a large number of individuals of a species with various variations of inherited traits.

“Natural selection,” writes C. Darwin, “acts exclusively by preserving and accumulating changes that are favorable under those organic and inorganic conditions to which every creature is exposed in all periods of its life. From the point of view of our theory, the continued existence of our organisms does not present any difficulty, since natural selection, or the survival of the fittest, does not necessarily imply progressive development, but only picks up the changes that appear, favorable to the creature that possesses them in difficult conditions his life. Natural selection - this must never be forgotten - acts only for the benefit of a given being and through this benefit ...

Natural selection leads to a divergence of characters and a significant extermination of less advanced and intermediate forms of life.

Based on the idea of natural selection, Charles Darwin determined the paths of evolutionary transformations.

He considered the main point in the evolutionary process divergence of symptoms or divergence (lat.divergo - “I deviate”, “I depart”). The divergence of traits leads to a decrease in competition, because organisms, thanks to new properties, were able to use different conditions of existence. Along this path, with the help of divergence, new species are formed from pre-existing species that correspond to new environmental conditions.

Natural selection Darwin considered the main driving force of evolution. The following phenomena are the result of this force: 1) a gradual complication and an increase in the level of organization of living beings; 2) adaptation of organisms to environmental conditions; 3) variety of species.

With the help of natural selection, according to Darwin, in nature, new species are formed from already existing species.

Darwin came to conclusions about the role of natural selection after a thorough study of the history of the emergence of new animal breeds and varieties. cultivated plants. Under conditions of domestication, the selection is performed by man. From the variety of options determined by variability, a person selects the form that best suits his interests. Darwin called this purposeful creation of new species artificial selection(Fig. 47). The study of the mechanism and results of artificial selection turned out to be an important step for Darwin on the way

substantiation of the theory of natural selection and its action in nature without human participation.

Darwin's doctrine of the evolution of the organic world explains the fitness (adaptation) of organisms to environment and considers the diversity of species as an inevitable result of the action of natural selection in connection with the divergence of inherited traits. Adaptations (Latin adaptatio - “fitting”, “adaptation”) is a set of morphological-physiological, behavioral, population and other adaptive features of a species that provide it with the ability to exist in certain environmental conditions. Adaptations give the structure and life of organisms the features of functional expediency that arose under the influence of natural selection. Darwin emphasized that any adaptive property is relative in nature, since it is useful to the body only in its specific, habitual habitat. However, even in a familiar environment, other, more perfect adaptations of organisms to external conditions are always possible.

Charles Darwin discovered the driving forces of evolution, to which he attributed heredity, variability, the struggle for existence and natural selection. At the same time, he also noted the great role of the ability of organisms to reproduce according to the type of geometric progression. For the first time in science, Darwin emphasized the role of species in evolution and proved that modern species (in nature and domestication) evolved from pre-existing species.

Having created scientific theory evolution, Darwin comprehensively substantiated historical method in the study of nature. The theory of the origin of species has fundamentally changed ideas about the evolution of the organic world and has become the largest scientific achievement significant event in the 19th century. The fundamental nature of Darwin's theory made representatives of all biological sciences relate their ideas to its provisions. The modern general understanding of evolution is also based on the teachings of Darwin.

1. What are the main conclusions in evolutionary theory C. Darwin?

2*. Explain the mechanism of natural selection. 3*. Prove your opinion.

Why did Darwin's teachings turn out to be more convincing than those of J.B. Lamarck?

What is the meaning of Ch. Darwin in the concept of "struggle for existence"?

§ 38 Modern ideas about the evolution of the organic world

Modern evolutionary doctrine is often called synthetic. This is because it includes not only Darwinism (that is, Ch. Darwin's ideas about selection and the struggle for existence), but also the discoveries of genetics, taxonomy, morphology, biochemistry, physiology, ecology and other sciences.

Particularly productive for the development of the theory of evolution were the data of genetics and molecular biology. The chromosome theory and the gene theory revealed the causes of mutations and the mechanisms of heredity transmission, and the molecular theory

biology and molecular genetics have figured out how to store, implement and transmit genetic information using DNA. It was found that elementary unit of evolution, capable of responding to changes in the environment by rearranging its gene pool is a population. According to this discovery, not a species, but its populations are saturated with mutations, which serve as the main material of the evolutionary process under the influence of natural selection.

The modern doctrine of evolution is based on the population concept.

Population (Latin populus - “people”, “population”) is a structural unit of a species. It is represented by a set of individuals of a species that have a common gene pool and occupy a certain territory within the range (distribution area) of this species. Populations are subject to the action of different directions of natural selection, since territorial isolation prevents the frequent exchange of genetic information between isolated populations (Fig. 48). Therefore, gradually between such populations occurs divergence) for a number of genetic traits. They accumulate through mutations. Moreover, individuals of populations acquire noticeable differences from the original, parental species. If the differences that have appeared ensure the non-crossing of individuals of one population with individuals of other populations of the original species, then the isolated population becomes an independent new species, isolated by divergence from the original species.

A population is the smallest subdivision of a species that changes over time. Therefore, the population is called the elementary unit of evolution.

In modern evolutionary teaching, such concepts as elemental

the mental unit of evolution, the elementary phenomena of evolution, the elementary material of evolution and the elementary factors of evolution.

Each population is characterized by the following properties: area, number and density of individuals, genetic heterogeneity (variety) of individuals, age and sex structure, special functioning in nature (intrapopulation, interpopulation contacts and relationships with other species and with the environment). Sexual contacts between individuals within the same population are much easier and more frequent than with individuals from different populations of the same species. Therefore, changes accumulating in one population with the help of recombinations, mutations, and natural selection determine its qualitative and reproductive isolation (divergence) from other populations. These changes in populations are called elementary phenomena of evolution. Changes in individual individuals do not lead to evolutionary changes, since a significant accumulation of similar inherited traits is needed, and this is available only to an integral group of individuals, which is a population.

The elemental material of evolution serves as hereditary variability (combinative and mutational) in individuals of a population. It is well known that both types of genotypic variability are observed in all studied prokaryotes and eukaryotes. Both of these types of variability can affect all the characteristics and properties of organisms (morphological, physiological, chemical, and behavioral) that can vary, which leads to the emergence of both qualitative and quantitative phenotypic differences in the population. Under certain conditions and for some time, new inherited traits that have arisen can reach sufficiently high concentrations in one or several adjacent populations of the species. Groups of individuals with such new characters can be found on "their" territory within the range of the species.

Elementary Factors of Evolution include such phenomena as natural selection, mutation, population waves, and isolation.

Natural selection eliminates individuals with unsuccessful combinations of genes from the population and preserves individuals with genotypes that do not violate the process of adaptive morphogenesis. Natural selection directs evolution.

mutation process maintains the genetic heterogeneity of natural populations.

population waves supply massive elementary evolutionary material for natural selection. Each population is characterized by a certain fluctuation in the number of individuals in the direction of either increase or decrease. These fluctuations in 1905 domestic genetic scientist S.S. Chetverikov named waves of life.

Isolation provides barriers that prevent free interbreeding of organisms. It can be expressed in territorial-mechanical (spatial, geographical) or

biological (behavioral, physiological, ecological, chemical and genetic) incompatibility (Fig. 49).

By disrupting crossbreeding, isolation divides the original population into two or more that differ from each other, and fixes the differences in their genotypes. The divided parts of the population are already independently subjected to the action of natural selection.

Isolation, the mutation process and population waves, being factors of evolution, influence the evolution of the species, but do not direct it. The direction of evolution is set by natural selection.

1. Replace the highlighted words of the statement with a term.

The smallest subdivision of a species, which changes over time, is involved in the formation of new species.

Divergence of signs of organismsCh. Darwin used to explain

of the diversity of forms in the evolution of organisms.

2*. What is the difference modern teaching about evolution from Darwin's evolutionary theory? 3. Think.

Why is a population called the structural unit of evolution?

How does natural selection direct the course of evolution?

§ 39 Type, its criteria and structure

View is one of the main the most complex concepts in biology. This concept allows not only to systematize the huge variety of living organisms on Earth, but also to solve the problem of the ways, causes, and mechanisms of speciation and evolution of living nature.

A species is a really existing genetically indivisible unit of the living world.

The concept of the form underlies the evolutionary theory of Ch. Darwin. Each species has its characteristic life cycle, within which certain processes of growth and development of the bodies of individuals take place, changes in the manifestations of the relationship of organisms with the environment and the alternation of methods of their reproduction.

A species is made up of populations. The commonality of genes inherited from ancestors and characterizing this species, maintained between populations with the help of individuals. Changes in populations lead to species change.

A species is the main structural unit in the system of organisms, a qualitative stage in the evolution of life.

In the early 60s. 20th century the American evolutionist scientist E. Mayr proposed a "biological concept" of a species, putting forward the following ideas: species are characterized not by difference, but by isolation; species do not consist of individuals, but of populations; the main feature of the species is its reproductive isolation from others. Mayr's views strengthened the concept of a species as a diverse polytypic system consisting of various intraspecific structural subdivisions - populations. The idea of a polytypic species is now accepted by all evolutionary scientists in different countries, and the doctrine of evolution is revealed on the basis of the population concept.

A strict definition of the concept of "species" in biology has not yet been created. Most often, a species is considered as a collection of separate groups of similar individuals - populations. Due to different populations, the species makes fuller use of the diversity of the environment in its range and, therefore, is better adapted to the living conditions. At the same time, the species acts as an integral and independent natural formation, characterized by its history of formation, a special evolutionary “destiny”.

To characterize the species, five main criteria (features) are used: morphological, physiological-biochemical, ecological, geographical and reproductive.

Morphological criterion allows you to distinguish between different types of external and internal features. For example, the genus currant contains several types of currants that are well distinguished from each other in appearance: black,

red, golden, alpine, Tien Shan, beautiful etc. They have different colors of flowers and fruits, on the shoot differently inflorescences are located, there are some differences in the shape of the leaves (Fig. 50).

Physiological and biochemical criterion fixes the dissimilarity chemical properties different kinds. So, all types of currants are specific in terms of the composition of proteins, sugars and other organic compounds in plant cells, which is easily detected even by the taste of their fruits, by the aroma of flowers, fruits, leaves, buds, and bark.

Geographic criterion indicates that each species has its own range. For example, the area black currant are northern regions Eurasia, while the range golden currant - central territories of North America, Tyanyan currant - forest belt of the mountains of the Central

Tien Shan in Central Asia.

Environmental criterion makes it possible to distinguish species according to the complex of abiotic and biotic conditions in which they formed, adapting to life. So, black currant arose in conditions of significant soil moisture, its natural thickets are often found along river banks, in lowlands in flood meadows,

while golden currant

formed in arid conditions of steppe foothills and does not grow in damp places. In artificial plantations (in gardens and parks), these two species sometimes

are grown nearby, but they bloom in different dates: black currant blooms in early spring currant golden- in the first half of summer.

Reproductive criterion causes the reproductive (genetic) isolation of the species from others, even closely related ones. All species have special mechanisms that protect their gene pool from the influx of foreign genes. This is achieved mainly by the peculiarities of the genotype in individuals of each species -

the number and structure of its chromosomes. The genetic criterion is the most significant, since it controls the reproductive isolation of the species.

The isolation of species is also achieved by a number of other auxiliary mechanisms, for example, a mismatch in the timing of reproduction in different species, a difference in ritual behavior during crossing, observed in many animals, morphological differences in reproductive organs, etc. If, for example, plants accidentally pollinate a flower with pollen from another species or in animals - random mating, then in the vast majority of cases, male germ cells in a new environment for them will die without having carried out (usually not even reaching the egg) fertilization.

Interbreeding is rare in nature. However, the hybrids that have arisen in this way are either unviable and soon die, or sterile.

Each species is a genetically closed system reproductively isolated from other species.

In reality, the species exists in the form of populations. And although a species is a single genetic system, its gene pool is represented by gene pools of populations. Having accumulated in large numbers over time, new gene variations in the gene pool of a population can lead to its isolation from other populations of this species. In this way, new species arise. That is why the population, as the smallest subdivision of a species that changes over time, is considered the elementary unit of evolution.

1. Name the types of plants and animals you know that live near your home or school.

2*. What mechanisms prevent interbreeding between different species?

3. Why is the reproductive criterion considered the most important characteristic of a species?

§ 40 Speciation processes

Speciation- the most complex process in the development of living matter. The emergence of a new species is always accompanied by a rupture of ties with the parent species and transformation into a new, separate set of populations and organisms. The new kind may be formed from one population or a group of adjacent populations.

The emergence of a new species is the central event of evolution.

The problem of speciation was fundamentally solved by Charles Darwin, who showed the role of divergence (divergence of traits), natural selection, and acute intraspecific competition between organisms.

According to modern concepts, speciation is carried out due to populations that have accumulated stable genotypic and phenotypic differences of an adaptive nature. These differences result in the isolation of the population and the formation of a new, independent species. Evolutionary processes occurring in populations on the basis of hereditary variability under the control of natural selection and leading to the formation of new species,

called microevolution.

The formation of species is determined by many reasons. In some cases, this occurs as a result of spatial-territorial (geographical) isolation, which prevents the regular exchange of genetic information. In other cases, this process may be caused by the expansion of the species into new conditions outside its range. In third cases, the formation of a new species may be due to biological (reproductive) isolation that arose suddenly, for example, due to polyploidy or mutation. Microevolution is the main way to increase the diversity of species on Earth and the total "sum of life" in the biosphere.

Microevolution leads to a change in the gene pool of a population within a species and to the formation of new species on Earth.

New species may arise from adjacent populations in different territories or within the range of the original species.

Geographic (alopatric) speciation arises as a result spatial-territorial isolation of one population or group of populations of a species. For example, individual populations in a species' range may be separated by mountains, rivers, deserts, highways, buildings, and other landscape barriers that hinder frequent gene exchange between populations.

Geographical isolation Charles Darwin explained the appearance of a variety of Darwin finches on several islands of the Galapagos archipelago in pacific ocean. It is likely that Darwin's finches are the descendants of several individuals of finches from South America, accidentally carried into the sea during a storm, settled and preserved on the Galapagos Islands. The finches that got there became the founders of populations on different islands. Isolated from each other, these populations after some time separated into new independent species.

The finches, blown away by the wind, having got to a separate island of the Galapagos archipelago, found themselves in an environment different from the one they left. At the same time, they were faced with the conditions of that particular island where they happened to be. Under the pressure of natural selection, the populations of finches evolved on different islands in different directions. In the process, they acquired an unusual appearance, the structure of the beak and peculiar habits, especially in obtaining food.

The same happens when a species spreads over a large area. As a result, the peripheral populations and their groups, which are more distant from the center of settlement, are intensively transformed in connection with the development of new habitats and become the ancestors of new species. An example is the species of dandelion in the territory of Eurasia or pike perch inhabiting water bodies.

Europe (Fig. 51).

pike perch

(Stizostedion lucioperka)

has a huge areola. It is distributed in the basins of the Baltic, Black, Azov and Caspian Seas. Inhabits the rivers

clear lakes and seas. Pike perch enters the salty waters of the seas for fattening, but spawns only in fresh water. Pike perch (S. volgensis] lives in the rivers of the basins of the Caspian, Azov and Black Seas, but is found there mainly in the lower and middle reaches of the rivers, where it spawns. It does not go far into the sea for fattening, it keeps mainly fresh waters. Bersh is smaller in size common zander, and it has no fangs on its lower jaw. Sea pike perch (S. marinusj - large, but different pike-perch Iberian smaller eyes, fewer branched rays in the dorsal fin. Unlike other zanders, the sea zander does not enter rivers at all, avoids desalinated areas and spawns in the sea on rocky coastal areas.

It is characteristic that these types of pike perch can simultaneously be in the same water basins, but do not interbreed, since they have already isolated themselves from each other.

New species may also arise due to the discontinuity (mosaic) of the range. An example of such a process is the emergence of closely related dandelion species from a widely distributed parent species.

The original species of dandelion millions of years ago occupied a vast territory of the entire continent of Eurasia. Changes in soil and climatic conditions in this area, the appearance of mountains, steppes, deserts, saline and damp soils led to the emergence of numerous species of dandelion (more than 200 species) living in cold, temperate and subtropical zones. Widespread species common dandelion (Taraxacum officinale) preserved in meadows, forest clearings, along roadsides and in weedy places near housing. Dandelion kok-saghyz (T. kok-saghyz) was formed in a hot arid climate on hard brackish soil. Unlike common dandelion, dandelion kok-saghyz leaves are narrow, deeply dissected, and the milky vessels of the root contain a significant percentage of rubber. In the highlands, in the cold alpine meadows of the Central Tien Shan, the species dandelion pink (T. roseum), looks very similar in appearance common dandelion, but with inflorescences of pink reed flowers.

Geographic speciation always proceeds rather slowly. This process goes on for hundreds of thousands of generations of individuals in the population. Only for such long periods of time in isolated populations of a species, with the help of their organisms, special signs and properties are developed that lead to reproductive isolation.

Sympatric (biological) speciation occurs within the range of the original species as a result of biological isolation. It is carried out on the basis of a territorially unified population, which has clearly different forms of individuals. The emergence of new species during sympatric speciation can occur in various ways.

One of them is the emergence of new species with rapid genotype change. This occurs, for example, in polyploidy, when new forms are immediately genetically isolated from the parent species.

If polyploids that have arisen by chance in nature are capable of producing viable offspring and resisting natural selection, then they can quickly spread and coexist next to the original species. This mode of speciation is often found in plants and protozoa. In multicellular animals, it is rarely observed - only in some invertebrates, for example, in an earthworm.

New species can also arise during hybridization with subsequent doubling of the number of chromosomes. This is how many cultivated plant species arose. For example,

cultivated plum (Prunus domestica) created by hybridization blackthorn (Pr. spinosa)

cherry plum (Pr. divaricata)c subsequent duplication of chromosomes.

Another way of sympatric speciation is due to ecological events, for example: seasonal isolation of populations within a species; isolation due to the production of other digestive enzymes in connection with the transition to feeding on another plant species (often observed in aphids); isolation caused by the appearance of special behavior in individuals.

3. Combinative variability in populations and its role in evolution

Three sources of combinative variability are known: crossing over, the random nature of the divergence of homologous chromosomes in meiosis, and the random nature of fertilization.
If we assume that in each pair of homologous chromosomes there is only one pair of allelic genes, then in humans (the haploid set of chromosomes is 23), the number of possible types of gametes will be 223, and the number of possible genotypes will be 323. This is 20 times more than the population of the Earth - and this is without taking into account the variety added by crossing over!
Thus, the possibility of the emergence of two identical organisms during sexual reproduction is practically zero (the exception is identical twins, the occurrence of which is not, strictly speaking, sexual reproduction).
Combination variability, like mutations, plays the role of a supplier of material for natural selection.
Hereditary variability in general (mutational, combinative) is random, non-directional. It only supplies material for selection. Hereditary variability itself, without the participation of other factors of evolution, cannot lead to a directed change in the gene pool of a population.

III. Consolidation of knowledge

IV. Homework

Study the paragraph of the textbook (factors of evolution, the role of mutational and combinative variability in evolution).

Lesson 3

I. Checking homework on the topic: “Elementary factors of evolution. Hereditary variability and its role in evolution"

Card work

1. More than 2 billion fruit flies have been studied by geneticists, and flies with blue or green eyes have never been observed among them. What is the probability of finding these mutations in the future?

2. How to explain the fact that albinism occurs in all human races and is widely distributed among mammals (cases of the appearance of white gorillas, tigers and other mammals are known)?

Oral knowledge test on:

1) the concept of the factors of evolution;
2) mutations and their role in evolution;
3) combinative variability and its role in evolution.

II. Learning new material

1. Waves of life and their role in evolution

The periodic alternation of ups and downs in the number of populations is called population waves, or waves of life (the term was introduced in 1905 by S.S. Chetverikov).
Invasions of voles, mice, locusts have been known to man since ancient times. Periodic fluctuations in numbers are especially noticeable in rodents and other species with a short life cycle and a rapid change of generations. But the phenomenon itself is characteristic of all populations of plants and animals.
Waves of life can be seasonal (periodic) and non-seasonal (non-periodic). Seasonal changes in population size are often genetically determined. Non-seasonal waves of life are due to the direct impact on the population of various abiotic and biotic environmental factors (temperature, humidity, the influence of predators, an abundance of food, drought, fire, flood, etc.). As a result, the population size is determined by many factors at once.
Communities often experience periodic population fluctuations associated with predator-prey relationships. Increased reproduction of predators' prey items due to an increase in food resources leads, in turn, to increased reproduction of predators. This is followed by the mass destruction of their victims. The lack of food resources causes a decrease in the number of predators and the restoration of the size of the prey population.
The waves of life are one of the elementary evolutionary factors. As the population increases, so does the number of mutants. After a population decline, the surviving part of the population will differ significantly in genetic composition from the previously numerous population, since some of the mutations will completely accidentally disappear along with the individuals carrying them, and some mutations, also by chance, will sharply increase their concentration.
Thus, population waves by themselves do not cause hereditary variability, but only contribute to a random change in the frequencies of alleles and genotypes, i.e. the waves of life are a kind of factor - a supplier of evolutionary material, bringing a number of genotypes into the evolutionary arena completely randomly and not directed. After stabilization of environmental conditions in the population, selection of individuals with optimal genotypes will take place.
It should be remembered that the waves of life threaten the survival of small populations.

2. Isolation and its importance for saturation of populations with mutations

Isolation in the theory of evolution is called the exclusion or difficulty of free interbreeding between individuals of the same species, leading to the isolation of intraspecific groups and new species.
There are various forms of isolation: geographical, temporal, ecological, seasonal, ethological, etc. All these forms can contribute to reproductive isolation. For example, geographic isolation prevents interbreeding due to the separation of populations by some geographic barriers (rivers, mountains, deserts, etc.). Thus, it disrupts the exchange of genetic information between populations of the same species.
Thus, isolation is one of the most important evolutionary factors contributing to the saturation of a given population with mutations. It reinforces interpopulation differences in the frequencies of occurrence of various genotypes and promotes the creation of groups with independent gene pools that can become independent species.

3. Gene flow and its role in evolution

If the isolation between neighboring populations is incomplete, then an exchange of genes occurs between them as a result of free crossing of their individuals. This process is called gene flow.
Gene flow is an important source of variability. Part of the migrant individuals of one population penetrates into another, and their genes are included in the gene pool of this population. When crossing individuals from different populations, the genotypes of the offspring will differ from the genotypes of both parents. In this case, gene recombination occurs at the interpopulation level, i.e. the gene stream is also a supplier of material for natural selection. The flow of genes has the most important biological consequence - the unification of all populations into a single species system.

4. Genetic drift as a factor in evolution

A random non-directional change in the frequency of genes in a population is called genetic drift. It is observed in small populations where the probability of chance is high.
Suppose that in a population a certain gene is represented by two alleles - the "+" allele and the "-" allele, and 50% of the individuals carry the "+" allele, and 50% carry the "-" allele. In each season, only 25% of the members of this population take part in breeding. By pure chance, in a particular year, there was only one individual carrying the “+” gene among them. As a result, this gene will occur much less frequently in the next generation; the frequency of occurrence of this gene will drop sharply - for completely random reasons not related to the characteristics of this gene.
An interesting case of genetic drift is the founder effect. When several individuals leave a large population and occupy a new area, the probability is very high that some genes will be represented here in a completely different ratio than in the original population. This circumstance can strongly influence the evolution of such newly emerging isolated populations. An example is Darwin's finches, the descendants of several South American finches that were swept out to sea during a storm and established a new population.
Thus, all the factors of evolution we have considered are non-directional. By themselves, they cannot cause a purposeful change in the gene pool of a population, i.e. cannot cause a purposeful change in the concentration of certain genes and cannot lead to an elementary evolutionary phenomenon.
The only directional factor is natural selection. All the factors discussed earlier can only increase or decrease its effectiveness.

III. Consolidation of knowledge

Generalizing conversation in the course of learning new material.

IV. Homework

Study the paragraph of the textbook (role in the evolution of life waves, isolation, gene flow, gene drift).

Purpose of the event: identify the level of mastering the educational material of the course by students " General biology at the end of the first half of the year.

The test is compiled on the topic: "Basic teachings about evolution" to the textbook A.A. Kamensky, E.K. Kriksunov, V.V. Pasechnik.

The estimated time to complete the administrative test is 40 minutes.

Topic"Fundamentals of the doctrine of evolution" is studied in the 11th grade in the course "General Biology" and is an extensive and rather complex topic.

During the study of this section, students get acquainted with the history of evolutionary ideas, with the works of C. Linnaeus, the teachings of J. B. Lamarck, the evolutionary theory of Ch. Darwin, the role of evolutionary theory in the formation of the modern natural-science picture of the world is studied. Students are introduced to the synthetic theory of evolution. They study the population as a structural unit of a species, a unit of evolution; driving forces of evolution, their influence on the gene pool of the population.

To reliably determine the level of assimilation theoretical material It is advisable for each student to use test control. The test includes the ability not only to reproduce knowledge, but also to apply it to formulate worldview conclusions and generalizations. In addition, testing is a qualitative and objective way of assessing the knowledge of students, it puts all children on an equal footing, excluding the subjectivity of the teacher.

Testing tasks: to check the knowledge of the history of evolutionary ideas, the scientific merits of C. Linnaeus and J. B. Lamarck, C. Darwin; to systematize knowledge about the species, population, driving forces evolution and its results; check students' understanding of macroevolution and speciation, the main directions of evolution of the organic world.

Download:

Preview:

Option 1

Part 1

one is correct.

A1. Which of the scientists considered the striving for perfection to be the driving force of evolution and claimed the inheritance of acquired traits?

Karl Liney
Jean-Baptiste Lamarck
Charles Darwin
A.N. Chetverikov

A2. A set of freely interbreeding individuals of the same species, which exists for a long time in a certain part of the range relatively apart from other sets of the same species, is called:

population
Variety
The colony

A3. What criterion of species include the features of external and internal structure field mouse?

Morphological
genetic
Ecological
Geographic

A4. What criterion of species refers to the totality of environmental factors to which the polar bear is adapted?

Morphological
genetic
Ecological
Geographic

A5. Population statistics include:

Mortality
population
fertility
growth rate

A6. What is a random non-directional change in the frequencies of alleles and genotypes in populations called?

Mutational variability
population waves
Gene drift
Insulation

A7. What are periodic and non-periodic fluctuations in the population size in the direction of increasing or decreasing the number of individuals called?

Waves of life
Gene drift
Insulation
Natural selection

A8. An example of an intraspecific struggle for existence is the relationship:

Black cockroaches among themselves
Black and red cockroaches
Black cockroaches with pesticides
Black cockroaches and black rats

A9. What form of struggle for existence is the most intense?

A10. What form of natural selection operates under gradually changing environmental conditions?

Driving natural selection

A11. Biological isolation is due to:

A small number of species
Impossibility of mating and fertilization
Geographic barriers
combinative variability

A12. Which group of evidence for the evolution of the organic world includes the similarity of the embryos of reptiles and birds?

Comparative anatomical
Embryological
Paleontological
biogeographic

A13. Specify the correct scheme for classifying animals:

A14. What organs arise as a result of convergence?

Homologous
Similar
atavistic
Rudimentary

A15. Which of the following devices not is an aromorphosis?

The origin of the spine in chordates
Elephant's trunk
Formation of a 3-chambered heart in amphibians

Part 2

three correct answers out of six.

IN 1. What evolutionary changes can be attributed to aromorphoses?

The appearance of a flower
Formation of organs and tissues in plants
The emergence of thermophilic bacteria
Atrophy of roots and leaves in dodder
Specialization of some plants for certain pollinators
Constant body temperature

IN 2. Evolutionary factors include:

Divergence
hereditary variability
Convergence
Struggle for existence
Parallelism
Natural selection

Administrative test in biology for the 1st half of the 11th grade

On the topic "Basic teachings about evolution"

to the textbook A.A. Kamensky, E.K. Kriksunov, V.V. Pasechnik

Option 2

Part 1

For each task A1-A15, 4 answer options are given, of which only one is correct.

Karl Liney
Jean-Baptiste Lamarck
Charles Darwin
A.N. Chetverikov

A2. The structural unit of a species is...

Individual
population
The colony
flock

A3. To what criterion of species is the set of chromosomes characteristic of Homo sapiens referred: their number, size, shape?

Morphological
genetic
Ecological
Geographic

A4. To what criterion of species is the growth of Grouse large-flowered in forests on rocky places?

Geographic
Morphological
Ecological
ethological

A5. Population dynamics include:

Mortality
population
Density
Structure

A6. Cause of population waves is not:

Seasonal temperature fluctuations
Natural disasters
Aggressiveness of predators
Mutational variability

A7. What prevents the exchange of genetic information between populations?

Mutational variability
population waves
Gene drift
Insulation

A8. What is the name of the complex of various relationships between organisms and factors of inanimate and living nature:

Natural selection
Struggle for existence
Fitness
Variability

A9. What form of struggle for existence is the perch eating its fry?

Interspecific
Intraspecific
With adverse environmental conditions
Intraspecific Mutual Assistance

A10. What form of natural selection tends to preserve mutations that lead to less variation in the average value of a trait?

Driving natural selection
Tearing natural selection
Stabilizing natural selection
Disruptive natural selection

A11. What evolutionary factor contributes to the emergence of barriers to free interbreeding of individuals?

Waves of life
Natural selection
Modifications
Insulation

A12. To which group of evidence for the evolution of the organic world do phylogenetic series belong?

Comparative anatomical
Embryological
Paleontological
biogeographic

A13. Indicate the correct scheme for classifying plants:

Species genus family order class type
species genus family order class type
species genus family order class department
Species genus order family class type

A14. What organs arise as a result of divergence?

Homologous
Similar
atavistic
Rudimentary

A15. Which of the following adaptations is classified as an idioadaptation?

The emergence of the chord
The emergence of a creeping stem in strawberries
Formation of 2 circles of blood circulation
Loss of circulatory organs in bull tapeworm

Part 2.

When completing tasks B1-B2, selectthree correct answers out of six.

When completing tasks B3-B4, establish a correspondence between the contents of the first and second columns. Enter the numbers of the selected answers in the table.

IN 1. What are the characteristics of biological progress?

Species decline
Expansion of the range of the species
The emergence of new populations, species
Narrowing of the range of the species
Simplify organization and transition to a sedentary lifestyle
Increasing the number of species

IN 2. What features illustrate the stabilizing form of natural selection?

Operates in changing environmental conditions
Operates under constant environmental conditions
Maintains the reaction rate of the trait
Changes the average value of a feature either in the direction of decreasing its value, or in the direction of increasing
Controls functioning organs
Leads to a change in the rate of reaction

IN 3. Establish a correspondence between the death of plants and the form of the struggle for existence.

AT 4. Establish a correspondence between the sign of an animal and the direction of evolution to which it corresponds

C1. What type of natural selection is shown in the figure? Under what environmental conditions does it occur? What mutations does it retain?

INSTRUCTIONS FOR CARRYING OUT

Administrative testIN BIOLOGY IN 11 CLASS

(I half of 2013-2014 academic year)

Purpose of the event:to identify the level of mastering the educational material of the course "General Biology" by students based on the results of the 1st half of the year.

The test is compiled on the topic: "Basic teachings about evolution" totextbook A.A. Kamensky, E.K. Kriksunov, V.V. Pasechnik.

The estimated time to complete the administrative test is 40 minutes.

Topic "Fundamentals of the doctrine of evolution" is studied in the 11th grade in the course "General Biology" and is an extensive and rather complex topic.

In this section, students will become familiar with andthe history of evolutionary ideas, with the works of K. Linnaeus, the teachings of J. B. Lamarck, the evolutionary theory of Ch. Darwin, the role of evolutionary theory in the formation of the modern natural-science picture of the world is being studied. Students are introduced to the synthetic theory of evolution. They study the population as a structural unit of a species, a unit of evolution; driving forces of evolution, their influence on the gene pool of the population.

To reliably determine the level of assimilation of theoretical material by each student, it is advisable to use test control. The test includes the ability not only to reproduce knowledge, but also to apply it to formulate worldview conclusions and generalizations. In addition, testing is a qualitative and objective way of assessing the knowledge of students, it puts all children on an equal footing, excluding the subjectivity of the teacher.

Testing tasks: to check the knowledge of the history of evolutionary ideas, the scientific merits of C. Linnaeus and J. B. Lamarck, C. Darwin; to systematize knowledge about the species, population, driving forces of evolution and its results; check students' understanding of macroevolution and speciation, the main directions of evolution of the organic world.

Test evaluation criteria.

All tasks are divided by difficulty levels.

Basic level tasks correspond to a minimum of content biological education and requirements for the level of training of graduates. They are compiled in accordance with the standard of secondary biological education. Each question has multiple answers, of which only one is correct. For the correct performance of each such task, 1 point.

Tasks of an increased level are aimed at testing the development of more complex content by students. They contain tasks with a choice of several answers from the given ones, to establish correspondence, to determine the sequence of biological phenomena, to indicate the truth or falsity of statements. For the correct performance of each such task, 2 points each.

The part C task includes a free answer task. For the correct performance of the task is set 3 points.

Work structure:

1) According to the content, the work includes the following blocks:

Type and its criteria
Populations

2) According to the levels of tasks, the work allows you to identify the assimilation of the material at the basic, advanced and high levels.

3) By forms test items the work consists of tests with the choice of one correct answer, open type with a short answer, open type with a full detailed answer.

Distribution of work tasks by content:

Blocks	Test item numbers	Number of jobs	Percentage of tasks for this block
Development of the evolutionary teachings of Charles Darwin			6,7%
Type e its criteria	A2, A3, A4
Populations			6,7%
Genetic composition and changes in the gene pool of populations	A6, A7		13,3%
The struggle for the existence of her form	A8, A9		13,3%
Natural selection and its forms	A10		6,7%
isolation mechanisms. Speciation	A11		6,7%
Macroevolution and its evidence	A12		6,7%
The system of plants and animals - a display of evolution	A13		6,7%
The main directions of evolution of the organic world	A14, A15		13,3%
TOTAL-10			100%

Distribution of work tasks in parts.

Parts of work	Number of jobs	Maximum primary score	Job type
Part 1 (A)			Choice of answer
Part 2 (B)			With a short answer
Part 3 (C)			With extended answer
Total

Distribution of work tasks by level of complexity:

Task difficulty level	Test item numbers	Number of jobs	Percentage of tasks for a given level of difficulty
Base	A1-A15		57,7%
elevated	B1-B4		15,5%
Tall			3,8%

Answers to the tasks of the administrative test:

Option 1

Option 2

A1 - 2

A2 - 2

A3 - 1

A4 - 3

A5 - 2

A6 - 3

A7 - 1

A8 - 1

A9 - 1

A10 - 2

A11 - 2

A12 -2

A13 - 1

A14 - 2

A15 - 2

A1 - 2

A2 - 2

A3 - 2

A4 - 3

A5 - 1

A6 - 4

A7 - 4

A8 - 2

A9 - 2

A10 - 3

A11 - 4

A12 - 3

A13 - 3

A14 - 1

A15 - 2

B1 - 1, 2, 6

B2 - 2, 4, 6

IN 3 -

AT 4 -

B1 - 2, 3, 6

B2 - 2, 3, 5

IN 3 -

AT 4 -

C1:

Stabilizing selection
Observed under relatively constant environmental conditions
Retains mutations leading to less variability in the mean value of the trait

C1:

1) Driving selection

2) Observed in unidirectional change in environmental conditions

3) Keeps mutations leading to other extreme manifestations of the magnitude of the trait (either in the direction of strengthening or in the direction of weakening)

total:0
In contact with 0
Google+ 0
OK 0
Facebook 0