Population- a set of individuals of the same species, occupying a certain area, freely interbreeding with each other, giving fertile offspring and in some way isolated from other populations. A population is a structural unit of a species and a unit of evolution.
Range - area of distribution of the population.
Depending on the size of the area and the nature of the distribution, cosmopolitans, ubiquists, and endemics are distinguished.
Cosmopolitans - species of plants and animals, representatives of which are found on a large part of the inhabited areas of the Earth (fly, rat).
Ubiquists - species of plants and animals with a wide ecological valence, are able to exist in a variety of environmental conditions, have extensive ranges (common reed, wolf).
Endemics- species of plants and animals that have small limited ranges. They are found on islands of oceanic origin, in mountainous regions, etc.
Population indicators are static and dynamic. The static includes the number and density, and the dynamic - fertility, mortality, and the rate of population growth.
The complex of properties of a population aimed at increasing the probability of survival and leaving offspring is called an ecological strategy of survival. There are r-strategists (r-species, r-populations) and K-strategists (K-species, K-populations).
Populations are permanent (permanent) and temporal (temporary).
Permanent- populations that are relatively stable in space and time, capable of indefinitely long self-reproduction.
Temporal - populations that are unstable in space and time, incapable of long-term self-reproduction, over time either transforms into permanent ones, or disappear.
According to the method of reproduction, populations are divided into panmictic, clonal and clonal-panmictic. Panmitic populations are made up of individuals that reproduce sexually and are characterized by cross fertilization. Clonal half-lives consist of individuals for which only asexual reproduction is characteristic. Clonal-panmictic populations are formed by individuals with alternating sexual and asexual reproduction.
Control questions
1. What is a population?
2. What population indicators do you know?
3. What is an ecological survival strategy?
4. What groups of the population do you know depending on their distribution pattern?
5. Name characteristics r- and K- types.
6. What populations do you know by self-reproduction and by the way of reproduction?
7. What is population size and density?
Topic 1.4 Ecology of communities and ecosystems
Biocenosis(community) - a set of populations different types living in a certain area. The concept of "biocenosis" was introduced by Moebius (1877). The plant component of the biocenosis is called phytocenosis, the animal component is called the zoocenosis, and the microbial component is called the microbocenosis. The leading component in the biocenosis is the phytocenosis, which determines what the zoocenosis and microbocenosis will be like. Distinguish between species, spatial and ecological structure of the biocenosis. Species structure- the number of species forming the biocenosis and the ratio of their number or mass.
Spatial structure- the distribution of organisms of different species in space (vertically and horizontally).
Ecological structure- the ratio of organisms of different ecological groups.
Biotope- a certain territory with its characteristic abiotic factors of the environment (climate, soil).
Biogeocenosis- a set of biocenosis and biotope. The term "biogeocenosis" was proposed by the Russian scientist VN Sukachev. Ecosystem - a system of living organisms and the surrounding inorganic bodies, interconnected by the flow of energy and the circulation of substances. The term "ecosystem" was proposed by the English scientist A. Tensley (1935).
"Ecosystem" and "biogeocenosis"- concepts are close, but not synonyms. A biogeocenosis is an ecosystem within the boundaries of a phytocenosis. Each biogeocenosis is an ecosystem, but not every ecosystem is a biogeocenosis. Ecosystem is a more general concept. The single ecosystem of our planet is called the biosphere.
The types of connections between organisms are trophic, topical, phoric, and factory.
Trophic connections arise between species when one species feeds on another.
Topical- are manifested in the change by one type of habitat conditions of another species.
Foric- one species participates in the spread of another species.
Factory- one species uses waste products, dead remains, or even living individuals of another species for its structures.
There are the following functional groups of organisms in the ecosystem: producers, consumers, reducers, detritus feeders.
Food chains are of two types: grazing and detrital.
Food chains can be represented as ecological pyramids: pyramid of numbers (Elton's pyramid), pyramid of biomass, pyramid of energy (production).
Biological production (productivity) is the increase in biomass in an ecosystem created per unit of time.
Biological productivity is primary and secondary. Primary is divided into gross and net. The mass of organisms in a particular group or community as a whole is called biomass.
Control questions
1. Give the definitions of the concepts of biocenosis, biotope, biogeocenosis, ecosystem.
2. What is the difference between the concepts of biogeocenosis, ecosystem?
3. What structures of biocenosis do you know? Describe them?
4. What are the types of connections between organisms?
5. What are the differences between the relationships between organisms?
6. What are the types of food chains?
7. What types of ecological pyramids are distinguished?
A population is a collection of individuals of one species, capable of self-reproduction, more or less isolated in space and time from other populations of the same species. Populations consist of single-species organisms that jointly inhabit certain areas and are interconnected by various relationships that provide them with a stable existence in a given natural environment.
Populations are the main elements of ecological systems, representing a set of co-living organisms of different species and conditions of their existence. The organisms that make up the population are related to each other in various relationships: they jointly participate in reproduction, can compete with each other for certain types of resources, can eat each other, or together defend against a predator.
Population Is a collection of individuals of the same species, capable of self-reproduction, more or less isolated in space and time from other similar assemblies of the same species.
A population has biological properties inherent in its constituent organisms, and group properties inherent only in the population as a whole. Like an individual organism, a population grows, differentiates and maintains itself. But such properties as fertility, mortality, age structure are characteristic only for the population as a whole.
When describing populations, two groups of quantitative indicators are used: static, characterizing the state of the population at a certain point in time, and dynamic, characterizing the processes occurring in the population over a certain period of time. Total number the population is expressed by a certain number of individuals. Various methods are used to assess it. When it comes to large and well-visible organisms, aerial photography is used. In other cases, the tagging method is used. Animals are caught, tagged and released back into nature. After a while, a new capture is made and the population size is determined by the proportion of labeled animals.
In biotic communities, each population plays its assigned role, constituting, together with populations of other species, a kind of natural unity that develops and operates according to its own laws. It is thanks to the functioning of populations that conditions are created that contribute to the maintenance of life on our planet. Occupying this or that space, building shelters, moving, using certain types of food, the populations of each species in a certain way affect surrounding nature... The circulation of substances, energy exchange between living and inanimate nature depends on populations. Cooperative activity populations determines many important properties of biotic communities and ecological systems.
MUNICIPAL BUDGETARY EDUCATIONAL INSTITUTION
"SECONDARY EDUCATIONAL SCHOOL No. 1"
CREDIT ON TOPIC
"BIOSPHERE"
(theoretical part)
tests in the form of exam
GENERAL BIOLOGY
9 - 11 CLASS
prepared
biology teacher
Andreeva Elvira Yurievna
Norilsk - 2010
Test option number 1
(theme "Biosphere")
The test consists of 3 parts.
ecosystem 3) biosphere
noosphere 4) species
changes their habitat
hydrosphere 3) lithosphere
atmosphere 4) life on Earth
more simple
biogeocenosis 3) biosphere
animals 3) mushrooms
bacteria 4) plants
anthropogenic 4) biotic
animal type 3) kingdom
plant department 4) biogeocenosis
gas 3) concentration
oxygen 3) climate
A. plants D. bacteria
What is the biomass of land, soil and oceans?
Test option number 2
(theme "Biosphere")
The test consists of 3 parts.
The first part contains questions under the letter A. In them you only need to choose one correct answer.
The second part contains questions under the letter B. These tasks can be:
or to choose several correct answers;
assignments to establish correspondences of positions between processes and objects, as well as a description of their properties and characteristics;
tasks to determine the sequence of biological phenomena or processes
The third part (under the letter "C") includes a detailed answer to the question posed.
creation of reserves
biogeocenoses 3) biorhythms
biosphere 3) biosphere
biogeocenosis 4) a nature reserve
declining biodiversity
To Linnaeus 3) V.I. Vernadsky
space energy
energy of the sun
C1. Give a detailed answer to the next question.
C2. Give a detailed answer to the next question.
The doctrine of the biosphere.
Test option number 3
(theme "Biosphere")
The test consists of 3 parts.
The first part contains questions under the letter A. In them you only need to choose one correct answer.
The second part contains questions under the letter B. These tasks can be:
or to choose several correct answers;
assignments to establish correspondences of positions between processes and objects, as well as a description of their properties and characteristics;
tasks to determine the sequence of biological phenomena or processes
The third part (under the letter "C") includes a detailed answer to the question posed.
enhance photosynthesis
gas 4) concentration
zakaznik 3) community
agroecosystem 4) forest park
gas 3) storage
chemical 4) biological
reserves 3) reserves
biogeocenoses 4) natural parks
IN 1. Choose a few correct statements. The gas function of living matter includes the following processes:
D. breathing process
C1. Give a detailed answer to the next question.
C2. Give a detailed answer to the next question.
Test option number 4
(theme "Biosphere")
The test consists of 3 parts.
The first part contains questions under the letter A. In them you only need to choose one correct answer.
The second part contains questions under the letter B. These tasks can be:
or to choose several correct answers;
assignments to establish correspondences of positions between processes and objects, as well as a description of their properties and characteristics;
tasks to determine the sequence of biological phenomena or processes
The third part (under the letter "C") includes a detailed answer to the question posed.
A1. The set of populations of different species, related to each other by food and energy ties as well as factors inanimate nature, the circulation of substances that have been living in a certain territory for a long time is called:
ecosystem 3) biosphere
noosphere 4) species
A2. In the circulation of substances, the greatest role is played by:
abiotic factors 3) living organisms
anthropogenic factors 4) biological rhythms
A3. The main reason for the decline in the number of species on Earth in the twentieth century is the anthropogenic factor, since it:
weakens competition between species
changes their habitat
contributes to the lengthening of food chains
influences seasonal changes in nature
A4. The youngest of all spheres of the Earth is the biosphere, since it arose only with the emergence of:
hydrosphere 3) lithosphere
atmosphere 4) life on Earth
A5. The reason for the decrease in soil fertility under the influence of man is:
application of fertilizers 3) erosion, salinization
creation of forest belts in the steppe 4) alternation of cultivated plants
A6. Biotechnological methods of food production are more effective because they:
more simple
allow you to get environmentally friendly products
does not require special conditions
does not require skilled labor
A7. The ecosystem created by man for the cultivation of cultivated plants is called:
biogeocenosis 3) biosphere
agrocenosis 4) experimental station
A8. In most ecosystems, the primary source of organic matter and energy is:
animals 3) mushrooms
bacteria 4) plants
A9. The source of energy for photosynthesis in plants is light, which is attributed to the factors:
non-periodic 3) abiotic
anthropogenic 4) biotic
A10. Living organisms during the existence of the biosphere have repeatedly used the same chemical elements thanks to:
synthesis of substances by organisms 3) circulation of substances
the breakdown of substances by organisms 4) the constant supply of substances from Space
A11. The structural and functional unit of the biosphere is
animal type 3) kingdom
plant department 4) biogeocenosis
A12. The reason for the negative human impact on the biosphere, manifested in the violation of the oxygen cycle, is:
creation of artificial reservoirs 3) reduction of forest area
irrigation of lands 4) drainage of swamps
A13. What function of living matter underlies its ability to accumulate chemical elements from the environment?
gas 3) concentration
redox 4) biogeochemical
A14. The most actively involved in the circulation of substances and the transformation of energy in the biosphere are:
oxygen 3) climate
living matter 4) the warmth of the earth's interior
IN 1. Choose a few correct statements. The biosphere includes:
A. plants D. bacteria
B. bio-inert substance D. biogenic substance
B. living matter E. inert matter
C1. Give a detailed answer to the next question.
What are the reasons for the stability of the biosphere?
C2. Give a detailed answer to the next question.
What are the main functions of the living matter of the biosphere?
Test option number 5
(theme "Biosphere")
The test consists of 3 parts.
The first part contains questions under the letter A. In them you only need to choose one correct answer.
The second part contains questions under the letter B. These tasks can be:
or to choose several correct answers;
assignments to establish correspondences of positions between processes and objects, as well as a description of their properties and characteristics;
tasks to determine the sequence of biological phenomena or processes
The third part (under the letter "C") includes a detailed answer to the question posed.
A1. Preserving the diversity of plant and animal species in the biosphere great importance It has:
creation of reserves
expansion of the area of agrocenoses
increasing the productivity of agrocenoses
pest control of agricultural plants
A2. A closed, balanced cycle of substances in an ecosystem causes:
self-regulation 3) ecosystem changes
fluctuations in population size 4) ecosystem stability
A3. Russian scientist V.I. Vernadsky created the doctrine about:
biogeocenoses 3) biorhythms
the leading role of living matter in the biosphere 4) photoperiodism
A4. The introduction of low-waste technologies into industrial production allows:
protect the biosphere from pollution
increase the productivity of agrocenoses
accelerate the circulation of substances in the biosphere
slow down the circulation of substances in the biosphere
A5. The coniferous forest is inhabited by many species associated with each other and with factors of inanimate nature, therefore it is called:
biosphere 3) biosphere
biogeocenosis 4) a nature reserve
A6. The greatest role in the circulation of substances is played by (em)
abiotic factors 3) anthropogenic factors
limiting factors 4) living matter
A7. Removal by a person of a significant amount of biomass from the ecosystem makes the cycle of substances unbalanced, which causes:
unstable ecosystem 3) self-regulation in the ecosystem
stable ecosystem 4) increase in population size
A8. The mass of living matter in the biosphere is very small, but it plays a huge role in ...
creation of the lithosphere 3) the creation of the World Ocean
transformation of matter and energy 4) the formation of continents
A9. The negative consequences of human impact on the biosphere are manifested in:
changes in atmospheric pressure
regulation of the population of game animals
declining biodiversity
creation of new varieties of plants and animal breeds
A10. The change by organisms in the process of life of the habitat in the ecosystem is the reason:
circulation of substances 3) the emergence of adaptations in organisms
changes in ecosystems 4) the emergence of new species
A11. Industrial waste - salts of heavy metals: lead, cadmium - cause poisoning in people, the birth of freaks, getting into their body:
in the process of reproduction 3) with inhaled air
on power circuits 4) with waste water
A12. For the first time the name "Biosphere" was given to:
To Linnaeus 3) V.I. Vernadsky
J. B. Lamarck 4) V.N. Sukachev
A13. The biosphere exists mainly due to:
space energy and intraplanetary thermal energy
intraplanetary thermal energy
space energy
energy of the sun
A14. The upper boundary of the biosphere is limited:
bird flight altitude 3) ozone layer
spore detection height 4) has no upper bound
IN 1. Choose a few correct statements. The functions of living matter in the biosphere include:
A. accumulative G. concentration
B. redox D. gas
B. conductive E. oxidative
C1. Give a detailed answer to the next question.
What is the significance of the cycle of substances in nature for the existence of the biosphere? Give examples.
C2. Give a detailed answer to the next question.
The doctrine of the biosphere.
Test option number 6
(theme "Biosphere")
The test consists of 3 parts.
The first part contains questions under the letter A. In them you only need to choose one correct answer.
The second part contains questions under the letter B. These tasks can be:
or to choose several correct answers;
assignments to establish correspondences of positions between processes and objects, as well as a description of their properties and characteristics;
tasks to determine the sequence of biological phenomena or processes
The third part (under the letter "C") includes a detailed answer to the question posed.
A1. The process of periodic population decline under the influence environmental factors up to a certain limit and its subsequent increase is called:
biological rhythm 3) self-regulation
circulation of substances 4) migration of atoms
A2. Destruction process by decomposers organic matter to inorganic and their return to the environment - an important link in:
metabolism 3) circulation of substances
self-regulation 4) seasonal changes in the life of organisms
A3. Mass cutting of dominant, habitat-forming tree species in the forest can lead to:
increasing the circulation of substances 3) lengthening food chains
the emergence of food chains 4) ecosystem changes
A4. Acid rain, which forms as a result of atmospheric pollution with nitrogen and sulfur oxides, lead to:
improving the mineral nutrition of plants
destruction of forests in several regions of the world
improving water exchange in plants
enhance photosynthesis
A5. Photosynthesis and respiration are related to the function of living matter:
redox 3) biogeochemical
gas 4) concentration
A6. In many countries of the world, parties of the "green" have been created, whose actions are aimed at:
protection of the biosphere 3) protection of human rights to clean air
refusal to use any technique 4) suspension of the development of the biosphere
A7. Ecosystems where shooting is prohibited rare species animals collecting plants are called:
zakaznik 3) community
agroecosystem 4) forest park
A8. A large species diversity, self-regulation, balanced circulation of substances are the signs of:
agroecosystems 3) unstable ecosystem
sustainable ecosystem 4) ecosystem development
A9. The ability of organisms to convert some substances into others and the formation of salts, oxides is the function of living matter:
gas 3) storage
concentration 4) redox
A10. The biosphere as a global ecosystem consists of:
biotic and chemical components
biotic and dead components
living and chemical components
biotic and abiotic components
A11. The living matter of the biosphere is formed by a set of individuals of all types:
animals, including humans 3) plants and humans
plants and animals 4) living organisms inhabiting the planet and humans
A12. Biogenic migration of atoms is called ... circulation:
biochemical 3) biogeochemical
chemical 4) biological
A13. All types of plants and animals and their natural environment are protected in:
reserves 3) reserves
2) biogeocenoses 4) natural parks
A14. Despite the constant use by plants of inorganic substances absorbed from the soil, their supply in the soil does not dry out, as it happens:
metabolism 3) circulation of substances
change of biogeocenoses 4) self-regulation
IN 1. Choose a few correct statements. The gas functions of living matter include the following processes:
A. the return of molecular nitrogen to the atmosphere by bacteria
B. assimilation of molecular nitrogen of the atmosphere by nodule bacteria
C. the ability to accumulate a certain substance in the cells of horsetails and sedges
D. breathing process
E. accumulation of iodine in cells seaweed kelp
E. accumulation chemical substances in the cells of organisms
C1. Give a detailed answer to the next question.
Name the components and boundaries of the biosphere.
C2. Give a detailed answer to the next question.
What are the reasons for the stability of the biosphere?
The key to answering biosphere tests.
option | |||
In nature, each existing species is a complex complex or even a system of intraspecific groups that encompass individuals with specific features of structure, physiology, and behavior. Such an intraspecific association of individuals is population.
The word "population" comes from the Latin "populus" - people, population. Hence, population- a set of individuals of the same species living in a certain territory, i.e. those that interbreed only with each other. The term "population" is currently used in the narrow sense of the word when talking about a specific intraspecific group inhabiting a certain biogeocenosis, and a wide, general sense- to designate isolated groups of a species, regardless of what territory it occupies and what genetic information it carries.
Members of one population exert on each other no less influence than physical factors of the environment or other species of organisms living together. In populations, to one degree or another, all forms of relationships characteristic of interspecific relations are manifested, but the most pronounced mutualistic(mutually beneficial) and competitive. Populations can be monolithic or consist of subpopulation level groupings - families, clans, herds, flocks etc. Combining organisms of the same species into a population creates qualitatively new properties. Compared to the lifetime of an individual organism, a population can exist for a very long time.
At the same time, the population resembles an organism as a biosystem, since it has a definite structure, integrity, a genetic program of self-reproduction, and the ability to autoregulate and adapt. The interaction of people with species of organisms in the environment, in the natural environment or under human economic control is usually mediated through populations. It is important that many of the laws of population ecology apply to human populations.
Population is a genetic unit of a species, changes of which are carried out by the evolution of the species. As a group of co-living individuals of the same species, the population acts as the first supraorganism biological macrosystem. The population's adaptive capabilities are significantly higher than that of its constituent individuals. The population as a biological unit has certain structure and functions.
Population structure characterized by its constituent individuals and their distribution in space.
Population functions are similar to the functions of other biological systems. They are characterized by growth, development, the ability to maintain existence in constantly changing conditions, i.e. populations have specific genetic and ecological characteristics.
Populations have laws that thus allow the use of limited environmental resources in order to ensure the abandonment of offspring. Populations of many species have properties that allow them to regulate their numbers. Maintaining the optimal number under the given conditions is called homeostasis of the population.
Thus, populations, as group associations, have a number of specific properties that are not inherent in each individual individual. The main characteristics of populations: size, density, fertility, mortality, growth rate.
The population is characterized by a certain organization. The distribution of individuals over the territory, the ratio of groups by sex, age, morphological, physiological, behavioral and genetic characteristics reflect population structure. It is formed, on the one hand, on the basis of the general biological properties of the species, and on the other, under the influence of abiotic factors of the environment and populations of other species. The structure of populations is therefore adaptive.
The adaptive capabilities of the species as a whole as a system of populations are much wider than the adaptive characteristics of each individual individual.
Population structure of the species
The space or area occupied by a population can be different both for different species and within the same species. The size of the population range is determined to a large extent by the mobility of individuals or the radius of individual activity. If the radius of individual activity is small, the size of the population area is usually also small. Depending on the size of the occupied territory, one can distinguish three types of populations: elementary, ecological and geographic (Fig. 1).
Rice. 1. Spatial subdivision of populations: 1 - species area; 2-4 - respectively geographic, ecological and elementary populations
Distinguish between sex, age, genetic, spatial and ecological structure of populations.
Sex structure of the population represents the ratio of individuals of different sex in it.
Age structure of the population- the ratio in the composition of the population of individuals of different ages representing one or different offspring of one or more generations.
Genetic structure of the population is determined by the variability and diversity of genotypes, the frequencies of variations of individual genes - alleles, as well as the division of the population into groups of genetically close individuals, between which, during crossing, there is a constant exchange of alleles.
Spatial structure of the population - the nature of the placement and distribution of individual members of the population and their groupings in the area. The spatial structure of populations differs markedly in sedentary and nomadic or migratory animals.
Ecological structure of the population is the division of any population into groups of individuals that interact in different ways with environmental factors.
Each species, occupying a certain territory ( area), represented on it by a system of populations. The more complexly the territory occupied by the species is dissected, the more opportunities are there for the isolation of individual populations. However, the population structure of a species is no less determined by its biological characteristics, such as the mobility of its constituent individuals, the degree of their attachment to the territory, and the ability to overcome natural barriers.
Isolation of populations
If members of a species are constantly mixing and mixing over vast areas, such a species is characterized by a small number of large populations. When weak developed abilities to move within the species, many small populations are formed, reflecting the mosaic nature of the landscape. In plants and sedentary animals, the number of populations is in direct proportion to the degree of heterogeneity of the environment.
The degree of isolation of neighboring populations of the species is different. In some cases, they are sharply separated by a territory unsuitable for habitation, and are clearly localized in space, for example, the populations of perch and tench in lakes isolated from each other.
The opposite option is the continuous settlement of vast territories by the view. Within the same species, there can be populations with both well distinguishable and blurred boundaries, and within a species, populations can be represented by groups of different sizes.
Links between populations support the species as a whole. Too long and complete isolation of populations can lead to the formation of new species.
Differences between individual populations are expressed to varying degrees. They can affect more than just them group characteristics, but also the qualitative features of the physiology, morphology and behavior of individual individuals. These differences are created mainly by the influence natural selection, adapting each population to the specific conditions of its existence.
Classification and structure of populations
An obligatory feature of a population is its ability to independently exist in a given territory for an indefinitely long time due to reproduction, and not an influx of individuals from the outside. Temporary settlements of various sizes do not belong to the category of populations, but are considered intrapopulation subdivisions. From this point of view, the species is represented not by a hierarchical subordination, but by a spatial system of neighboring populations of different scales and with different degrees of connections and isolation between them.
Populations can be classified according to their spatial and age structure, density, kinetics, constancy or change of habitats, and other ecological criteria.
The territorial boundaries of populations of different species do not coincide. The variety of natural populations is also expressed in the variety of types of their internal structure.
The main indicators of the structure of populations are the number, the distribution of organisms in space and the ratio of individuals of different quality.
The individual traits of each organism depend on the characteristics of its hereditary program (genotype) and on how this program is implemented in the course of ontogenesis. Each individual has a certain size, gender, distinctive features morphology, behavioral features, their limits of endurance and adaptability to environmental changes. The distribution of these traits in a population also characterizes its structure.
The population structure is not stable. The growth and development of organisms, the birth of new ones, death from various causes, changes in environmental conditions, an increase or decrease in the number of enemies - all this leads to a change in various ratios within the population. Because of what the structure of the population in a given period of time, the direction of its further changes largely depends.
Sex structure of populations
The genetic mechanism of sex determination provides a split of the offspring by sex in a ratio of 1: 1, the so-called sex ratio. But it does not follow from this that the same ratio is typical for the population as a whole. Sex-linked traits often define significant differences in physiology, ecology, and behavior between females and males. Due to the different viability of the male and female organisms, this primary ratio often differs from the secondary and especially from the tertiary, which is characteristic of adults. So, in humans, the secondary sex ratio is 100 girls to 106 boys, by the age of 16-18 this ratio is leveled out due to the increased male mortality and by the age of 50 it is 85 men per 100 women, and by the age of 80 - 50 men per 100 women.
The sex ratio in a population is established not only according to genetic laws, but also, to a certain extent, under the influence of the environment.
Age structure of populations
Fertility and mortality, population dynamics are directly related to the age structure of the population. The population consists of individuals of different age and sex. Each species, and sometimes each population within a species, is characterized by its own ratio of age groups. In relation to the population, they usually distinguish three ecological ages: pre-reproductive, reproductive and post-reproductive.
With age, the requirements of an individual to the environment and resistance to its individual factors naturally and very significantly change. At different stages of ontogenesis, a change in habitat, a change in the type of nutrition, the nature of movement, and the general activity of organisms can occur.
Age differences in a population significantly increase its ecological heterogeneity and, consequently, resistance to the environment. The likelihood increases that at strong deviations of conditions from the norm, at least a part of viable individuals will remain in the population, and it will be able to continue its existence.
The age structure of populations is adaptive. It is formed on the basis of the biological properties of the species, but it also always reflects the strength of the impact of environmental factors.
Age structure of plant populations
In plants, the age structure of the cenopopulation, i.e. the population of a particular phytocenosis is determined by the ratio of age groups. The absolute, or calendar, age of a plant and its age state are not identical concepts. Plants of the same age can be in different age states. The age, or ontogenetic state of an individual is the stage of its ontogenesis, at which it is characterized by certain relationships with the environment.
The age structure of the cenopopulation is largely determined by the biological characteristics of the species: the frequency of fruiting, the number of seeds and vegetative primordia produced, the ability of vegetative primordia to rejuvenate, the rate of transition of individuals from one age state to another, the ability to form clones, etc. biological features, in turn, depends on the conditions external environment... The course of ontogenesis also changes, which can occur in one species in many variants.
Different plant sizes reflect different vitality individuals within each age group. The vitality of an individual is manifested in the power of its vegetative and generative organs, which corresponds to the amount of accumulated energy, and in resistance to adverse influences, which is determined by the ability to regenerate. The vitality of each individual changes in ontogeny along a one-peaked curve, increasing in the ascending branch of ontogeny and decreasing in the descending one.
Many meadow, forest, steppe species when grown in nurseries or crops, i.e. on the best agrotechnical background, reduce their ontogeny.
The ability to change the path of ontogenesis ensures adaptation to changing environmental conditions and expands ecological niche species.
Age structure of animal populations
Depending on the characteristics of reproduction, members of the population may belong to the same generation or to different ones. In the first case, all individuals are close in age and approximately simultaneously go through the next stages of the life cycle. The timing of reproduction and passage of individual age stages is usually confined to a specific season of the year. The number of such populations, as a rule, is unstable: strong deviations of conditions from the optimum at any stage of the life cycle affect the entire population at once, causing significant mortality.
In species with a single reproduction and short life cycles, several generations are replaced during the year.
When humans exploit natural animal populations, taking into account their age structure is of paramount importance. In species with a large annual recruitment, a larger part of the population can be removed without the threat of undermining its numbers. For example, in pink salmon, ripening in the second year of life, it is possible to catch up to 50-60% of spawning individuals without the threat of a further decrease in the population size. For chum salmon, maturing later and having a more complex age structure, the rates of removal from a mature herd should be lower.
The analysis of the age structure helps to predict the size of the population over the course of the life of a number of the next generations.
The space occupied by the population provides it with a livelihood. Each territory can feed only a certain number of individuals. Naturally, the completeness of the use of available resources depends not only on the total population size, but also on the distribution of individuals in space. This is clearly manifested in plants whose feeding area cannot be less than a certain limiting value.
In nature, an almost uniform, ordered distribution of individuals in the occupied territory is rarely found. However, most often members of the population are distributed unevenly in space.
In each specific case, the type of distribution in the occupied space turns out to be adaptive, i.e. allows you to make optimal use of available resources. Plants in the cenopopulation are most often extremely unevenly distributed. Often the denser center of the cluster is surrounded by individuals that are less densely located.
The spatial heterogeneity of the cenopopulation is associated with the nature of the development of clusters in time.
In animals, due to their mobility, the methods of ordering territorial relations are more diverse than in plants.
In higher animals, the intrapopulation distribution is regulated by the instinct system. They are characterized by a special territorial behavior - a reaction to the location of other members of the population. However, a sedentary lifestyle is fraught with the threat of rapid depletion of resources if the population density is too high. The total area occupied by the population is divided into separate individual or group areas, thereby achieving an orderly use of food reserves, natural shelters, breeding grounds, etc.
Despite the territorial isolation of the members of the population, communication is maintained between them using a system of various signals and direct contacts at the borders of possessions.
"Securing the site" is achieved in different ways: 1) guarding the boundaries of the occupied space and direct aggression towards a stranger; 2) special ritual behavior that demonstrates a threat; 3) a system of special signals and labels indicating the occupation of the territory.
A common response to territorial marks — avoidance — is inherited in animals. The biological benefit of this type of behavior is clear. If the conquest of the territory was decided only by the outcome of a physical struggle, the appearance of each stronger alien would threaten the owner with the loss of the site and elimination from reproduction.
Partial overlapping of individual territories serves as a way to maintain contact between members of the population. Neighboring individuals often maintain a stable mutually beneficial system of ties: mutual warning of danger, joint protection from enemies. The normal behavior of animals includes an active search for contacts with representatives of their own species, which often intensifies during a period of decline in numbers.
Some species form broadly roaming groups that are not tied to a specific territory. This is the behavior of many fish species during feeding migrations.
There are no absolute distinctions between the different uses of the territory. The spatial structure of the population is very dynamic. It is subject to seasonal and other adaptive changes in accordance with the place and time.
The laws of animal behavior are the subject of a special science - ethology. The system of relationships between members of one population is therefore called the ethological, or behavioral structure of the population.
The behavior of animals in relation to other members of the population depends, first of all, because a single or group way of life is inherent in the species.
A solitary lifestyle, in which individuals of a population are independent and isolated from each other, is characteristic of many species, but only at certain stages of the life cycle. A completely solitary existence of organisms in nature does not occur, since it would be impossible to carry out their main vital function - reproduction.
The family lifestyle also strengthens the bonds between parents and their offspring. The simplest type of such connection is the care of one of the parents about the laid eggs: clutch protection, incubation, additional aeration, etc. In the family lifestyle, the territorial behavior of animals is most pronounced: various signals, markings, ritual forms of threat and direct aggression ensure the ownership of a plot sufficient for feeding offspring.
Larger animal associations - flocks, herds and colonies. Their formation is based on the further complication of behavioral relationships in populations.
Life in a group through the nervous and hormonal systems is reflected in the course of many physiological processes in the animal's body. In isolated individuals, the metabolic rate changes noticeably, reserve substances are spent more quickly, a number of instincts are not manifested and overall vitality worsens.
Positive group effect manifests itself only up to some optimal level of population density. If there are too many animals, it threatens everyone with a lack of environmental resources. Then other mechanisms come into play, leading to a decrease in the number of individuals in the group by dividing it, dispersing or falling fertility.
Properties of living organisms
1. Metabolism and energy with environment(the main sign of the living).
2. Irritability(ability to respond to influences).
3. Reproduction(self-reproducing).
Organizational levels of living matter
1. Molecular- this is the level of complex organic substances - proteins and nucleic acids. At this level, chemical reactions metabolism(glycolysis, crossing over, etc.), but the molecules themselves cannot yet be considered alive.
2. Cellular... At this level arises life, because a cell is a minimal unit that possesses all the properties of living things.
3. Organ-tissue- typical only for multicellular organisms.
4. Organizational- due to neuro-humoral regulation and metabolism at this level, homeostasis, i.e. maintaining the constancy of the internal environment of the body.
5. Population-specific... At this level, there is evolution, i.e. changes in organisms associated with their adaptation to their environment under the influence of natural selection. The smallest unit of evolution is the population.
6. Biogeocenotic(a set of populations of different species connected with each other and the surrounding inanimate nature). At this level, there is
- circulation of substances and transformation of energy, and
- self-regulation, due to which the sustainability of ecosystems and biogeocenoses is maintained.
7. Biosphere... At this level, there is
- global circulation substances and energy conversion, and
- interaction of living and nonliving matter planets.
Choose two correct answers out of five and write down the numbers under which they are indicated. At what levels of the organization of living things study the importance of photosynthesis in nature?
1) biosphere
2) cellular
3) biogeocenotic
4) molecular
5) tissue-organ
Answer
Choose the one that is most correct. What is the level of organization of living nature is a set of populations of different species connected with each other and the surrounding inanimate nature?
1) organismic
2) population-specific
3) biogeocenotic
4) biosphere
Answer
Choose the one that is most correct. Gene mutations occur at the level of organization of the living
1) organismic
2) cellular
3) species
4) molecular
Answer
Choose the one that is most correct. The elementary structure at the level of which the action of natural selection is manifested in nature
1) organism
2) biocenosis
3) view
4) population
Answer
Choose two correct answers out of five and write down the numbers under which they are indicated. What signs are similar for living and inanimate objects of nature?
1) cellular structure
2) change in body temperature
3) heredity
4) irritability
5) movement in space
Answer
Choose two correct answers out of five and write down the numbers under which they are indicated. At what levels of organization of living things are the features of the reactions of photosynthesis in higher plants studied?
1) biosphere
2) cellular
3) population-specific
4) molecular
5) ecosystem
Answer
Below is a list of concepts. All of them, except two, are the levels of organization of the living. Find two concepts that "fall out" of the general series, and write down the numbers under which they are indicated.
1) biosphere
2) gene
3) population-specific
4) biogeocenotic
5) biogenic
Answer
1. Establish the sequence in which the levels of organization of the living are located. Write down the corresponding sequence of numbers.
1) population
2) cellular
3) species
4) biogeocenotic
5) molecular genetic
6) organismic
Answer
2. Establish a sequence of increasing complexity of the levels of organization of the living. Write down the corresponding sequence of numbers.
1) biosphere
2) cellular
3) biogeocenotic
4) organismic
5) population-specific
Answer
1. Choose two correct answers out of five and write down the numbers under which they are indicated. The cellular level of organization coincides with the organismal level of
1) bacteriophages
2) amoeba dysentery
3) polio virus
4) wild rabbit
5) euglena green
Answer
2. Choose two correct answers out of five and write down the numbers under which they are indicated in the table. Cellular and organismic levels of life organization are simultaneously matched.
1) freshwater hydra
2) spirogyra
3) ulotrix
4) dysentery amoeba
5) cyanobacteria
Answer
3. Choose two correct answers. What organisms have the same cellular and organismic life levels?
1) sulfur bacteria
2) penicillus
3) chlamydomonas
4) wheat
5) hydra
Answer
Choose two correct answers out of five and write down the numbers under which they are indicated. One common amoeba is simultaneously found on:
1) Molecular level of organization of life
2) Population-specific level of organization of life
3) The cellular level of life organization
4) Tissue level of life organization
5) Organizational level of organization of life
Answer
1. Choose two correct answers out of five and write down the numbers under which they are indicated. Living is different from non-living
1) the ability to change the properties of an object under the influence of the environment
2) the ability to participate in the circulation of substances
3) the ability to reproduce their own kind
4) change the size of the object under the influence of the environment
5) the ability to change the properties of other objects
Answer
2. Choose two correct answers out of five and write down the numbers under which they are indicated. What signs are inherent only in living matter?
1) growth
2) movement
3) self-reproduction
4) rhythm
5) heredity
Answer
3. Choose two correct answers out of five and write down the numbers under which they are indicated. All living organisms are characterized by
1) the formation of organic substances from inorganic
2) absorption of mineral substances dissolved in water from the soil
3) active movement in space
4) breathing, nutrition, reproduction
5) irritability
Answer
4. Choose two correct answers out of five and write down the numbers under which they are indicated. What signs are characteristic only for living systems?
1) the ability to move
2) metabolism and energy
3) dependence on temperature fluctuations
4) growth, development and the ability to self-replicate
5) stability and relatively weak variability
Answer
5. Choose two correct answers out of five and write down the numbers under which they are indicated. Organisms, in contrast to objects of inanimate nature, are characterized by
1) change
2) movement
3) homeostasis
4) evolution
5) chemical composition
Answer
Establish a correspondence between the levels of organization of living things and their characteristics and phenomena: 1) biocenotic, 2) biosphere. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) processes cover the entire planet
B) symbiosis
C) the interspecies struggle for existence
D) transfer of energy from producers to consumers
D) evaporation of water
E) succession (change of natural communities)
Answer
Choose two correct answers out of five and write down the numbers under which they are indicated. Ontogenesis, metabolism, homeostasis, reproduction occur at ... levels of organization.
1) cellular
2) molecular
3) organismic
4) organ
5) tissue
Answer
Choose two correct answers out of five and write down the numbers under which they are indicated in the table. At the population-specific level of organization of life, there are
1) fish of Lake Baikal
2) birds of the Arctic
3) Amur tigers Primorsky Territory of Russia
4) city sparrows of the Park of Culture and Rest
5) European tits
Answer
Choose two correct answers out of five and write down the numbers under which they are indicated in the table. Which of the levels of life organization are supraspecific?
1) population-specific
2) organoid-cellular
3) biogeocenotic
4) biosphere
5) molecular genetic
Answer
Choose two correct answers out of five and write down the numbers under which they are indicated. Cellular level organization of life corresponds
1) chlamydomonas
2) sulfur bacteria
3) bacteriophage
4) kelp
5) lichen
Answer
Choose two options. Energy metabolism in an ordinary amoeba occurs at the level of organization of a living
1) cellular
2) biosphere
3) organismic
4) biogeocenotic
5) population-specific
Answer
Choose two correct answers out of five and write down the numbers under which they are indicated. At what level of organization do processes such as irritability and metabolism take place?
1) population-specific
2) organismic
3) molecular genetic
4) biogeocenotic
5) cellular
Answer
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