The population of our planet as of 2000 is 6055 million people. The world's population has grown at the fastest pace over the past two centuries. Such a sharp jump in population is called the "population explosion".
Nowadays, more than 9/10 of the increase falls on, first of all, and, and on the European continent during recent years there is a decrease in the absolute number of the population.
Life expectancy is different for men and women. In general, women in the world live 3 years longer than men. In many economically developed countries, the difference in life expectancy is 6-7 years in favor of women, reaching a maximum of 12 years in Russia (61 and 73 years). The main reason is the greater vitality of the female body, as well as the wider prevalence of harmful habits among men - alcoholism and smoking, more frequent accidents at work and in everyday life, murder and suicide. In most developing countries, the situation is much the same. Although among them there are those where the average life path for women is shorter (,). This is closely related to the early marriages of women, frequent childbirth, hard work.
Fertility, mortality, natural population growth
Fertility, mortality, natural population growth are basically biological processes. But nevertheless, the socio-economic conditions of life in society and in the family have a decisive influence on them. The mortality rate is primarily due to the level of human well-being and the degree of development of public health services. The birth rate also depends on the socio-economic structure of society, the living conditions of people. But this relationship is not straightforward. For example, while women are more actively involved in production and social life, the duration of the education of children and the costs of their upbringing increase, the birth rate decreases. This is one of the main reasons why relatively wealthy families often have no more children, and sometimes even fewer children, than less wealthy ones. However, income growth can also serve as a stimulus for an increase in the birth rate. It should also be borne in mind that the birth rate is determined by national and religious traditions, age of marriage, the strength of family foundations, the nature of settlement, climatic features (in hot conditions, sexual maturation of people occurs faster). Wars have a strong negative effect on population reproduction.
Population growth
Types and modes of population reproduction
In accordance with the change in the aggregate of demographic indicators, it is customary to distinguish three main historical types of population reproduction.
The first and earliest of them is the so-called archetype of population reproduction. He dominated in primitive society, which was at the stage of an appropriating economy, and is now very rare, for example, among some Indian tribes. The mortality rate among these peoples is so high that their numbers are declining.
The second type of reproduction, "traditional" or "patriarchal", dominates the agrarian or early stages of industrial society. The main distinctive features- very high birth and death rates, low average life expectancy. Large families are a tradition that contributes to the better functioning of the family in an agrarian society. High mortality is a consequence of the low standard of living of people, their hard work and poor nutrition, insufficient development of medicine.
The third - "modern" or "rational" type of population reproduction, is generated by the transition from an agrarian to an industrial economy. This type of reproduction is characterized by low fertility, close to the average mortality rate, low and high average life expectancy. It is typical for economically with more high level life and culture of residents. here it is closely related to the deliberate regulation of family size, and the mortality rate is primarily affected by the high percentage of elderly people.
Population dynamics is the process of changing its basic biological characteristics over time.
Population dynamics is one of the most significant biological and ecological phenomena. We can say that the life of a population is manifested in its dynamics, since a population cannot exist without constant changes, due to which it, as it were, adapts to constantly occurring changes in external conditions.
The main dynamic indicators of populations are fertility, mortality and population growth rate.
2.3.1. Fertility, mortality, migration of individuals.
The dynamics of the number and density of populations is closely related to fertility and mortality, as well as the ability of their constituent individuals to perform migration processes.
Fertility- This is an indicator characterizing the rate of increase in the population as a result of reproduction, that is, an indicator characterizing the rate of reproduction.
Distinguish absolute and specific fertility
Absolute or total fertility (P) is defined as the number of individuals (∆ N P ) born in the population for a certain period of time (∆ t ):
P =∆ N P / ∆ t
Specific fertility ( b ) Is the ratio of individuals (∆ N P ) born in a certain period of time (∆ t N ):
b = ∆ N P / ∆ t · N
This indicator is used to compare fertility among themselves in populations with different numbers.
For instance:
if there are 500 individuals in the population capable of breeding (N= 500) and within 10 days ( ∆ t ) 50 new individuals were born ( ∆ N P =50),
then the absolute or total fertility will be: P =∆ N P / ∆ t = 50/10 = 5,
and the specific fertility: b = ∆ N P / ∆ t · N = 50/10 500 = 0.01 or 1%
Distinguish maximum and actual fertility.
Maximum (physiological) fertility is the theoretical maximum of the birth rate of new individuals under ideal conditions in the absence of limiting environmental factors.
The maximum fertility is constant for a given population, and is determined only by the physiological characteristics of organisms (physiological fertility of females).
Living organisms have a huge potential for reproduction, therefore, with unlimited resources and ideal natural conditions, species realize the maximum fertility.
Each population is characterized by biotic (or reproductive) potential, i.e. the rate of increase in the number of individuals in the population in the absence of limiting environmental factors.
Biotic (or reproductive) potential is established theoretically as the rate at which, during continuous reproduction (possible only theoretically under ideal ecological conditions of existence), individuals of a certain species can cover Earth even layer.
For instance:
- for elephants, this speed is 0.3 m / s;
- for some microorganisms - hundreds of meters per second.
This means that in the absence of limiting environmental factors, such fast-breeding species as bacteria, insects, mice and some fish can increase their numbers to populate the entire surface of the Earth in a short period of time.
It is calculated that:
- bacteria divide every 20 minutes. At this rate, one cell in 36 hours produces offspring that can cover our entire planet with a continuous layer;
- one dandelion in less than 10 years is able to populate the globe with its descendants, if all the seeds germinate.
In reality, however, such a huge birth rate of organisms is never realized and the actual birth rate is much lower than the maximum.
Actual (or ecological) fertility characterizes the rate of reproduction of a population under actual conditions of life, i.e. in specific environmental conditions.
Mortality is the reciprocal of fertility.
Mortalityis an indicator that characterizes the rate of population decline as a result of the death of individuals.
Distinguish general and specific mortality.
Total mortality (C) is defined as the number of individuals killed in the population (∆ N m ) for a certain period of time (∆ t ):
C =∆ N m / ∆ t
Specific mortality ( d ) Is the ratio of individuals (∆ N m ) that died within a certain period of time (∆ t ), to the number of all individuals of the population ( N ):
d = ∆ N m / ∆ t · N
Distinguish minimum and actual mortality.
The minimum (physiological) mortality is the minimum possible mortality rate, which manifests itself even under ideal environmental conditions as a result of the physiological old age of individuals.
In this case, individuals implement the entire genetically determined cycle of the organism's life.
In specific environmental conditions actual (environmental) mortality , usually, above the minimum level, since under the influence of abiotic and biotic environmental factors, additional causes of the death of organisms are created.
Mortality affects the lifespan of organisms in a population and thus its age composition.
Depending on the age composition of populations, there are three types of mortality.
The first type of mortality is characterized by increased mortality of adults, mainly old individuals.
This type of mortality is observed:
- in insects whose larvae live in soil, water, wood or in other places with favorable conditions;
- in most large mammals that take care of their offspring for a long time;
- in people with proper nutrition and a healthy lifestyle.
The second type includes mortality, which is the same for all age groups.
Such mortality is very rare and only in populations that are constantly in extreme conditions:
- observed in some songbirds, reptiles and small mammals.
The third type of mortality is characterized by increased mortality of individuals in the early stages of their development.
This type of mortality is characteristic of most species of marine animals and plants:
- marine species of animals (oysters or other bivalve molluscs, as well as fish) give a huge offspring, but only some individuals survive to adulthood;
- plants that reproduce due to the dispersion of a large number of seeds, and in which the maximum death occurs at the stage of seed germination and shoots.
Usually mortality is presented graphically as "Survival curves" which express the dependence of the number of survivors out of 100 or 1000 individuals on their age.
According to the three types of mortality, three types of survival curves (fig. 1):
Fig. 1. Three types of survival curves
1 survival curve characterized by a slight decrease in mortality to the age of natural (“physiological”) mortality, followed by a sharp drop, reflecting the extinction of individuals that have reached this critical age;
2 survival curve - this is an ideal diagonal survival curve - it is presented in the form of a diagonally decreasing straight line and is characterized by an even distribution of mortality by age;
3 survival curve demonstrates a sharp drop in mortality in the area of younger ages, which is soon replaced by a gradual, relatively uniform decrease in the mortality of organisms that have survived the “critical” age.
There are also intraspecific differences in survival curves. The reasons can be different and are often gender related. For example, women live longer than men, so the survival curve for men is less convex compared to that for women.
In addition, the 2nd survival curve, built according to the inscriptions on the gravestones of people who lived in Ancient Rome in the 1st-1st centuries AD, is characteristic only for the ancient Romans, and for other nations - 1 survival curve.
Analysis of the curves of survival and mortality in different age groups opens up the possibility of calculating the life expectancy of individuals of a given age group, which is of great importance in applied ecological research.
The dynamics of the number and density of populations is greatly influenced by migration of individuals, which occur when individuals move from one habitat ( emigration) to another (immigration ).
Migrations- regular movements of living organisms between different habitats, spatially separated from each other. They occur for various reasons:
Changes in living conditions in habitats;
Changes in the requirements of living organisms to these conditions at different stages of development.
Basically, migrations take place during the growth of young animals and their resettlement.
The most intensive settlement occurs during unbalanced processes of fertility and mortality in the population. As a result of migration, an exchange of individuals of populations occurs, as a result of which the excess of individuals in one population is eliminated and compensated in another.
Migrations (daily, seasonal) allow organisms to use optimal environmental conditions in places where their permanent residence is impossible. They lead to the development of new biotopes, the expansion of the general range of the species, to the exchange of individuals between populations, increase the unity and general stability of the species, and contribute to the success in the struggle for existence.
In different populations, fertility, mortality and migration of individuals differ. They are specific for each species and depend on a variety of reasons that determine the characteristics of fertility, mortality and mobility of individuals.
Thus, the considered four variable factors - fertility, mortality, immigration and emigration determine the change in population size.
Individuals appear in the population due to birth and immigration, and disappear as a result of death and emigration:
change in population size = (fertility + immigration) - (mortality + emigration).
In the absence of migration, the change in population size depends on the ratio of fertility and mortality.
Fertility and mortality. Natural growth. Types of population reproduction. Demographic explosions and crises.
The population may increase as a result of natural or mechanical movement population. The natural movement of the population is characterized by indicators of fertility, mortality, marriage and divorce rates. Fertility and mortality rates are measured in ppm.
Fertility is the number of people born per year, per 1000 population. Mortality is the number of people who die per year, per 1000 population. The difference between fertility and mortality forms the natural increase or natural decline in the population of the country. Depopulation is a natural decline in the population. Marriage is the frequency of marriage. It is usually measured by the number of registered marriages per year per 1000 inhabitants or the number of those married per year per 1000 unmarried (unmarried) legal age groups. The result of marriage is the number of married people. Divorce is the frequency of divorce. Measured by the number of divorces per 1000 inhabitants per year or per 1000 existing married couples.
The natural movement of the population is an integral part of the process of population reproduction - the constant renewal of people. At its core, population reproduction is a biological process. But as far as historical development in human society, there has been a gradual change in the types of population reproduction. The theory that explains the change in the types of reproduction depending on the socio-economic development of the country is called the theory of demographic transition (demographic revolutions). The transition from one type of reproduction to another is called a demographic revolution. We need to know the historical types of reproduction and the patterns of demographic transition in order to understand the demographic processes taking place in Russia. Worldwide patterns of demographic development are manifested in each of the countries of the world.
Most ancient type reproduction archaic (archetype). The economic base of the ancient society was the appropriating economy (hunting and gathering). At the same time, man only used the food resources of the natural landscape. The population in a certain area was limited natural resources... The population could exist for a long time, provided that the population remained the same. The archetype is characterized by high fertility and high mortality (40-45 ppm). The natural increase was extremely insignificant. In fact, the number of people increased only as a result of the settlement of new territories.
The archaic type of reproduction was replaced by the traditional one. The transition was associated with the emergence and spread of manufacturing (agriculture) agriculture. Archaeologists have called it the Neolithic Revolution, the first economic upheaval in human history. The economic basis for the development of society has improved, there is a transition to a settled way of life, in addition, food and living conditions have improved (permanent settlements have appeared). As a result, the mortality rate dropped to 30-35 ppm, the birth rate remained at the same level of 40-45 ppm. There was a natural increase in the population, but it was also insignificant. Low life expectancy was promoted by low life expectancy (25-35 years) and high infant mortality (mortality of children under the age of 1 year - 200-300 ppm).
The traditional type of reproduction was replaced by the modern one. The transition began in the 17th century. v Western Europe in connection with the industrialization and urbanization of society. At the same time, nutrition and living conditions of people have sharply improved, the incidence of infectious diseases has decreased. As a result, life expectancy has increased and infant mortality has decreased. A rapid decline in mortality while maintaining high fertility rates leads to a sharp increase in natural growth at the initial stage of the demographic transition. This period, which is characterized by a sharp increase in the rate of population growth, is called the “population explosion”. After a while, following the decline in mortality, the birth rate also dropped. The following reasons for the decline in fertility can be distinguished:
reduction of child mortality (as a result of which there is no need to have "spare children");
s organization of social security (that is, the state takes care of the elderly, and children are no longer the only breadwinners in old age);
the collapse of the old patriarchal family (which was the cell of reproduction) and the emergence of small families, where the upbringing of a large number of children is difficult;
s emancipation of women and the emergence new system values, the main of which are now - "outside the home";
the growth of the level of education and the expansion of the range of interests of people;
the growth of costs for the upbringing and education of children (if in the agrarian economy children already from an early age "pay off" themselves by working on the land, now it is only necessary to "invest" money in them up to 20 years);
s urbanization is a kind of integral indicator of changes in conditions and lifestyles: in urbanized areas (and above all in large cities) all of the above factors are stronger.
Thus, the modern type of reproduction is characterized by low fertility and mortality (about 10 ppm) and, as a consequence, low natural increase or natural loss. Characteristic feature modern type of reproduction is the regulation of the number of children in the family.
At the beginning of the 20th century, Russia was close to the traditional type of population reproduction. The birth rate was about 45 ppm, the average life expectancy was about 35 years. Over the next decades, there was a demographic transition, which began in the northwestern and central provinces, the most industrialized and urbanized. The transition to the modern type of reproduction was complicated by several demographic crises - periods with negative natural growth.
The first demographic crisis was observed in 1914-1922. and was associated with the first world and Civil wars... The mortality rate in these years exceeded the birth rate, and the country's population fell sharply. The second crisis took place in 1933-34. and was associated with the famine that followed violent collectivization. Natural population decline was again observed. The third crisis happened in 1941-1945. and is associated with the Great Patriotic War. Over the years, the country's population has decreased by more than 10 million people.
Currently, Russia is undergoing the fourth demographic crisis in this century. The birth rate is approximately 9-10 ppm, and the mortality rate is 14-15 ppm. That is, about a million more people die in Russia every year than are born. This demographic crisis began back in 1992. Its causes are the socio-economic crisis in the country, the narrowed reproduction of the population (in each next generation of people less are born than in the previous one), the "demographic wave" of the crisis of 1941-1945, when very few people were born, and, accordingly, children ( 60s) and grandchildren (90s) they also have few.
It was accompanied by a modern demographic crisis and a decrease in life expectancy. If in the 70s and 80s. it was about 70 years, then by 1995 there was a decrease to 64 years (including 57 years for men and 71 years for women). Since 1996, there has been a slight increase in life expectancy. The period of the demographic explosion in Russia as a whole practically did not appear.
Within Russia, there are significant differences in the demographic situation associated with differences in national and gender-age composition in the regions of the country. There are 4 types of regions according to the demographic situation.
The first type is national autonomies in the south of the country. This type includes republics North Caucasus, Kalmykia, Tuva, Altai, Buryat Autonomous Okrugs. The indigenous population of these regions is at the final stage of the transition from the traditional type of reproduction to the modern one. Accordingly, here, with a low mortality rate (7-9 ppm), there is a fairly high birth rate (15-20 ppm) and a noticeable natural increase. The age structure of the population is "young", with the largest proportion of children in Russia.
The second type is the most urbanized regions of the country. These are Moscow, St. Petersburg, Moscow region and some other regions. Here the birth rate is minimal (6-8 ppm), the mortality rate is above average (15-17 ppm), the natural decline is more than average (9-10 ppm). The age structure of the population is similar to the average Russian, but the population has “advanced” to the greatest extent in the demographic transition, which explains the existing differences from others. In particular, it is in these regions that the minimum share of children in the population is observed.
The third type is Russian regions with a “young” age structure of the population, which was formed as a result of the influx of the population, mainly young people, over the past several decades. This type includes the regions of the European North, as well as most of the regions of the Asian part of Russia. In these regions, there is a low birth rate (7-10 ppm), but low mortality (9-11 ppm). As a result, there is a gain of about zero. Regions of this type are distinguished by the maximum share of the working-age population and the minimum share of the elderly.
The fourth type is Russian regions with an “old” age structure of the population, which was formed as a result of the migration outflow of the population over several decades. This type includes most regions of the European part of Russia (except for the regions included in other groups). Here the average birth rate (9-10 ppm), but the highest mortality (18-22 ppm). Regions of this type are distinguished by the maximum natural decline in population (10-13 ppm) and the maximum proportion of elderly people.
General demographic indicators of Russia
