In 1967, R. MacArthur and E. Wilson, analyzing the dynamics of population numbers, proposed r- and K-coefficients [MacArtur R.H., Wilson E.O., 1967]. We will not consider their mathematical meaning, but use these coefficients to designate two strategies for the evolutionary development of living beings.

The r-strategy assumes rapid reproduction and a short life expectancy of individuals, and the k-strategy implies a low reproduction rate and long life. In accordance with the r-strategy, the population develops at turning points in its history, when the external environment changes, which contributes to the emergence of new characteristics and the capture of new areas. The K-strategy is characteristic for the prosperity of a population in an already captured area and under relatively stable conditions. Obviously, the probability of innovation in a population will be higher, the faster it reproduces and the more often there is a change of generations, i.e. shorter lifespan of individuals. To solve the problem of transitional forms, the r-strategy is not enough; it is advisable to supplement it with one more property, namely increased viability, or better qualities in the struggle for existence, in the short (compared to the K-strategy) time period allotted by nature for the life of an individual. This is generally logical: you have to pay for increasing vitality, as well as for fertility, and this payment is a reduction in life expectancy. If the viability of individuals with the r-strategy is increased, this could compensate for the noted disadvantages of intermediate forms associated with the formation of a new function. As a result, they would survive the struggle for existence. Having accepted that the ability to switch r- and K-strategies is one of the mechanisms of biological evolution, we come to the question: how exactly does it work? In order to remain within the framework of the concept of evolution as the consolidation of randomly emerging new characteristics through natural selection, one must also accept that the switching of strategies occurs without any pattern, and those who choose the strategy that is more appropriate to the given environmental conditions survive. In the simplest case, there must be a single gene or a coordinated group of genes, the mode of operation of which determines the choice of strategy.

6. Anthropogenic influence on the cycles of basic nutrients in the biosphere.

7. The main stages of change in the relationship between man and nature in the course of its historical development.

8. The problem of global climate change on the planet: possible causes, consequences, solutions.

9. Desertification as a global environmental problem.

10.The problem of providing fresh water as a global environmental problem.

11.The problem of soil degradation: causes and consequences on a global scale.

12.Environmental assessment of the global demographic situation.

13.Global environmental problem of pollution of the World Ocean. What are the reasons and environmental dangers of this process?

14.The problem of reducing biological diversity: causes, environmental consequences, possible solutions to the problem.

15.Environmental factors: concept and classification. Basic mechanisms of action of environmental factors on living organisms.

16.Adaptation: the concept of adaptation, its ecological role.

17. Basic patterns of the action of environmental factors on living organisms.

18.Types of biotic relationships in nature, their ecological role.

19. Concepts – stenobiontity and eurybiontity.

20. The concept of population, its biological and ecological meaning.

21.Number, density, population growth. Regulation of numbers.

22. Fertility and mortality in a population: theoretical and ecological. Their determining factors.

23. Sex structure of the population and its determining factors.

24. Age structure of the population, main types of populations depending on the age ratio.

25.Spatial structure of the population and its determining factors.

26. Ethological (behavioural) structure of the population and its determining factors.

27.Ecological strategies of populations (r- and k-life strategies). Their ecological meaning.

28. Survival and survival curves of organisms in a population, the ecological meaning of survival curves.

29. Population growth curves, ecological significance of each stage of growth.

30. The concept of an ecosystem, its main components, types of ecosystems.

31. Pyramids of numbers, biomass, energy in ecosystems, their ecological meaning.

32.Energy flow in the ecosystem. 10% energy rule.

33.Flow of matter in an ecosystem. The fundamental difference between the flow of matter and energy.

34.Food chains. The effect of toxicant accumulation in food chains.

35. Productivity of ecological systems. The most productive ecosystems of the globe, their environmental problems.

36.Ecological succession, types of succession.

37.Producers, consumers and decomposers, their place in the food chain and ecological role in ecosystems.

38. The place and role of man in the ecological system.

39. Natural and artificial ecosystems, their environmental sustainability.

40. The concept of environmental pollution, natural and anthropogenic pollution.

41. The main types of anthropogenic impact on the environment: chemical, energy, biological pollution of the environment.

42.Ecological situation and human health. Human adaptation to extreme environmental factors.

43. Standardization of environmental quality: goals of regulation, types of standards.

44. The principles underlying the development of maximum permissible concentrations.

45.Habitat monitoring: concept, goals and types of monitoring.

46. ​​Environmental problems of the Far East.

27.Ecological strategies of populations (r- and k-life strategies). Their ecological meaning.

Adaptations of individuals in a population are ultimately aimed at increasing the likelihood of survival and leaving offspring. Among the adaptations, a complex called ecological strategy stands out. The ecological strategy of a population is its general characteristics of growth and reproduction. This includes the growth rate of its individuals, time to reach sexual maturity, fertility, frequency of reproduction, etc.

There are two survival strategies - the p strategy and the k survival strategy.

Ecological strategies of populations are highly diverse. Thus, when presenting the material on population growth and growth curves, the symbols r and K were used. Rapidly reproducing species have a high r value and are called r-species. These are, as a rule, pioneer (often called “opportunistic”) species of disturbed habitats. These habitats are called r-selective because they favor the growth of r-species.

Species with relatively low r values ​​are called K-species. Their reproduction rate is sensitive to population density and remains close to the equilibrium level determined by the value of K. These two types of species are said to use the r-strategy and the K-strategy, respectively.

These two strategies essentially represent two different solutions to the same problem - the long-term survival of the species. Species with a g-strategy quickly colonize disturbed habitats (exposed rock, forest clearings, burnt areas, etc.) than species with a K-strategy, because they spread more easily and reproduce faster. Species with a K-strategy are more competitive, and they usually displace r-species, which in the meantime move to other disturbed habitats. The high reproductive potential of g-species indicates that, if left in any habitat, they would quickly use up the available resources and exceed the supporting capacity of the environment, and then the population would die. Species with an r-strategy occupy a given habitat for one or at most several generations. Later they move to a new place. Individual populations may die out regularly, but the species moves and survives. In general, this strategy can be described as a “fight and flight” strategy.

It should be noted that different populations can use the same habitat in different ways, so species with r- and K-strategies can coexist in the same habitat. There are transitions between these extreme strategies. No species is subject to only r- or only K-selection. In general, r- and K-strategies explain the relationship between different qualitative characteristics of the population and environmental conditions.

28. Survival and survival curves of organisms in a population, the ecological meaning of survival curves.

Lifespan is the duration of an individual's existence. It depends on genotypic and phenotypic factors. There are physiological, maximum and average life expectancy. Physiological life expectancy (PLS) is the life expectancy that an individual of a given species could have had if it had not been influenced by limiting factors throughout its entire life. It depends only on the physiological (genetic) capabilities of the organism and is only possible theoretically. Maximum life span (MLS) is the life span to which only a small proportion of individuals can survive under real environmental conditions. It varies widely: from a few minutes in bacteria to several thousand years in woody plants (sequoia). Typically, the larger the plant or animal, the longer its lifespan, although there are exceptions (bats live up to 30 years, which is longer, for example, than the life of a bear). Average life expectancy (ALS) is the arithmetic average of the life expectancy of all individuals in a population. It fluctuates significantly depending on external conditions, therefore, to compare the life expectancy of different species, genetically determined LRM is more often used.

Survival rate is the absolute number of individuals (or percentage of the original number of individuals) surviving in a population over a certain period of time.

Z = n/n 100%,

where Z is survival rate, %; n – number of survivors; N – initial population size.

Survival depends on a number of reasons: the age and sex composition of the population, the action of certain environmental factors, etc. Survival can be expressed in the form of tables and survival curves. Survival tables (demographic tables) and survival curves show how the number of individuals of the same age in a population decreases as people age. Survival curves are constructed using data from survival tables.

There are three main types of survival curves. Type I curve is characteristic of organisms whose mortality rate is low throughout life, but increases sharply at the end of its life (for example, insects that die after laying eggs, people in developed countries, some large mammals). Type II curve is typical for species in which mortality remains approximately constant throughout life (for example, birds, reptiles). Type III curve reflects the mass death of individuals in the initial period of life (for example, many fish, invertebrates, plants and other organisms that do not care about their offspring and survive due to a huge number of eggs, larvae, seeds, etc.). There are curves that combine the features of the main types (for example, in people living in backward countries and some large mammals, curve I initially has a sharp drop due to high mortality immediately after birth).

The set of properties of a population aimed at increasing the probability of survival and leaving offspring is called an ecological survival strategy. This is a general characteristic of growth and reproduction. This includes the growth rate of individuals, time to reach maturity, fertility, frequency of reproduction, etc.

Thus, A.G. Ramensky (1938) distinguished the main types of survival strategies among plants: violents, patients and explerents. Violents (siloviki) - suppress all competitors, for example, trees forming indigenous forests. Patients are species that can survive in unfavorable conditions (“shade-loving”, “salt-loving”, etc.). Explerents (fillers) are species that can quickly appear where indigenous communities are disturbed - in clearings and burnt areas, on shallows, etc.

More detailed classifications also identify other intermediate types. In particular, it is possible to distinguish another group of pioneer species that quickly occupy newly emerging territories where there has not yet been any vegetation. Pioneer species partially have the properties of explorers - low competitive ability, but, like patients, they have high tolerance to the physical conditions of the environment.

Survival- the absolute number of individuals (or percentage of the original number of individuals) surviving in the population over a certain period of time:

Z = n/N * 100%, where Z is survival rate, %; n is the number of survivors; N is the initial population size.

Survival depends on a number of reasons: the age and sex composition of the population, the action of certain environmental factors, etc.

Survival can be expressed as survival curves, which reflect how the number of individuals of the same age in a population decreases as they age.

There are three main types of survival curves:

1. Type I curve characteristic of organisms whose mortality rate is low throughout life, but increases sharply at the end of it (for example, insects that die after laying eggs, people in developed countries, some large mammals);
2. type II curve characteristic of species in which mortality remains approximately constant throughout life (for example, birds, reptiles);
3. Type III curve reflects the mass death of individuals in the initial period of life (for example, many fish, invertebrates, plants and other organisms that do not care about their offspring and survive due to a huge number of eggs, larvae, seeds, etc.).

There are curves that combine the features of the main types (for example, in people living in backward countries and some large mammals, the type I curve initially has a sharp drop due to high mortality immediately after birth).

A set of properties of a population aimed at increasing the probability of survival and leaving offspring is called ecological survival strategy. There are two types of environmental strategies: r-strategy and K-strategy. The salient features are given below.

r-species (opportunistic species)	K-species (with a tendency towards equilibrium)
Reproduce quickly: high fertility, short generation time	Reproduce slowly: low fertility, long generation time
Reproduction rate does not depend on population density	Reproduction rate depends on population density, increasing rapidly if density falls
The species is not always stable in a given area	The species is stable in this area
Spread widely and in large quantities	Settling slowly
Small size of individuals	Large size of individuals
Short lifespan of an individual	Long lifespan of an individual
Weak competitors	Strong competitors
Better adapted to environmental changes (less specialized)	Less resistant to changes in environmental conditions (high specialization for life in stable habitats)
Examples: bacteria, aphids, annual plants	Examples: large tropical butterflies, condor, humans, trees

r-strategists (r-species, r-populations)- populations of rapidly reproducing, but less competitive individuals. They have a J-shaped growth curve that is independent of population density. Such populations spread quickly, but they are not stable. These include bacteria, aphids, annual plants, etc.

K-strategists (K-species, K-populations)- populations of slowly reproducing, but more competitive individuals. They have an S-shaped growth curve depending on population density. Such populations inhabit stable habitats. These include humans, condors, trees, etc.

“... two American scientists, Robert MacArthur and Edward Wilson, created the theory of R-K selection. The theory of two different strategies for the reproduction of living beings.

The theory of two strategies turned out to be so successful that it is used in a number of sciences, recognized by almost everyone, and included in textbooks and teaching aids.

The R-strategy is the birth of as many cubs as possible per unit time.

Each of them can be practically not taken care of, and each cub has not much chance of survival. A fly lays 5 million eggs - and is it really worried about the fate of these 5 million future little flies? Hundreds of thousands and millions of insects, crustaceans, and mollusks lay eggs. Fish that lay “only” tens of thousands of eggs, especially frogs that lay thousands of eggs, are simply ideal parents in comparison with simpler creatures. Of course, they also do not care about their offspring in any way, but these more complex animals are forced to spawn more complex, larger eggs - and thereby spawn fewer of these eggs. Some species of fish are already trying to protect their hatched fish: they build nests for them and attack emerging predators. Some species even keep the fry in their own mouth, and there the fry escape in case of danger.

These are already elements of the K-strategy: the birth of a small number of cubs, each of which is important and valuable. The more complex the species, the more valuable each individual life is for it, the fewer cubs die between birth and death. The simpler a living being is, the less it needs to be taught and prepared for life, the faster it becomes an adult.

A mouse can give birth to ten little mice three times a year. Giving birth to a mouse is very easy, and the babies become adults in three weeks. They can already take care of themselves, the mother kicks them out and is ready to give birth to new ones. If the little mice do not die, the world will soon be filled with hordes of adult mice. More complex animals - elephants, chimpanzees, moose, bison - have fewer cubs and die less often.

But even in large complex animals the physiological norm is mortality 60-70% newborns. A female chimpanzee and elephant gives birth 10-15 times in her life. 7, 10 or even 12 of these babies will die before they become adults. The same 2 or 3 cubs that are necessary for the reproduction of the species will grow up and give birth to a tribe.

After catastrophes due to volcanic explosions, after a tsunami, new islands and coasts are “captured” by living beings with an R-strategy. But soon larger, more complex animals with a K-strategy begin to dominate. Evolution is in many ways a struggle not for survival, but for dominance.”

Burovsky A.M., Brain phenomenon. Secrets of 100 billion neurons, M., “Yauza”; "Eksmo", 2010, p. 77-79.

Lifespan – the duration of an individual's existence. It depends on genotypic and phenotypic factors. There are physiological, maximum and average life expectancy. Physiological life expectancy (PLS) – This is the life expectancy that an individual of a given species could have had if it had not been influenced by limiting factors throughout its entire life. It depends only on the physiological (genetic) capabilities of the organism and is only possible theoretically. Maximum life expectancy (MLS) – This is the lifespan to which only a small proportion of individuals can survive under actual environmental conditions. It varies widely: from a few minutes in bacteria to several thousand years in woody plants (sequoia). Typically, the larger the plant or animal, the longer its lifespan, although there are exceptions (bats live up to 30 years, which is longer, for example, than the life of a bear). Average life expectancy (ALS) – This is the arithmetic average of the life expectancy of all individuals in the population. It fluctuates significantly depending on external conditions, therefore, to compare the life expectancy of different species, genetically determined LRM is more often used.

Survival– the absolute number of individuals (or percentage of the original number of individuals) surviving in the population over a certain period of time.

Z = n/n 100%,

Where Z– survival rate,%; p – number of survivors; N – initial population size.

Survival depends on a number of reasons: the age and sex composition of the population, the action of certain environmental factors, etc. Survival can be expressed in the form of tables and survival curves. Survival tables (demographic tables) And survival curves reflect how the number of individuals of the same age in a population decreases as they age. Survival curves are constructed using data from survival tables.

There are three main types of survival curves. Type I curve characteristic of organisms whose mortality rate is low throughout life, but increases sharply at the end of it (for example, insects that die after laying eggs, people in developed countries, some large mammals). Type II curve characteristic of species in which mortality remains approximately constant throughout life (for example, birds, reptiles). Type III curve reflects the mass death of individuals in the initial period of life (for example, many fish, invertebrates, plants and other organisms that do not care about their offspring and survive due to a huge number of eggs, larvae, seeds, etc.). There are curves that combine the features of the main types (for example, in people living in backward countries and some large mammals, curve I initially has a sharp drop due to high mortality immediately after birth).

A set of properties of a population aimed at increasing the probability of survival and leaving offspring is called ecological survival strategy. This is a general characteristic of growth and reproduction. This includes the growth rate of individuals, time to reach maturity, fertility, frequency of reproduction, etc.

Thus, A.G. Ramensky (1938) distinguished the main types of survival strategies among plants: violents, patients And explerents. Violents (siloviki) - suppress all competitors, for example, trees forming indigenous forests. Patients – species that can survive in unfavorable conditions (“shade-loving”, “salt-loving”, etc.). Explerents (filling) - species that can quickly appear where indigenous communities are disturbed - in clearings and burnt areas, on shallows, etc.

More detailed classifications also identify other intermediate types. In particular, it is possible to distinguish another group of pioneer species that quickly occupy newly emerging territories where there has not yet been any vegetation. Pioneer species partially have the properties of explorers - low competitive ability, but, like patients, they have high tolerance to the physical conditions of the environment.

Ecological strategies of populations are highly diverse. But at the same time, all their diversity lies between two types of evolutionary selection, which are denoted by the constants of the logistic equation: r- strategy and TO-strategy.

r-strategists (r-species, r-populations) – populations of rapidly reproducing but less competitive individuals. Have J-shaped curve of population growth, independent of population density. Such populations quickly spread, but they are not stable; they include bacteria, aphids, annual plants, etc.

K-strategists (K-species, K-populations)– populations of slowly reproducing, but more competitive individuals. Have S-shaped curve of population growth depending on population density. Such populations inhabit stable habitats. These include humans, trees, etc.