We explain what populations are, how they are classified and their growth. Also, what are its characteristics and examples.
What is population?
The term is usually used to refer to set of individuals (usually humans, but not exclusively) that make up a community or that inhabit a specific area or geographic space. It is frequently used in disciplines such as demography, ecology and statistics.
The study of populations dates back to Antiquitywhen the considered father of demography, the Arab Ibn Aljún (Abenjaldun in Spanish), composed his works in which he studied the formation of the Arab peoples, using statistical data for the first time in history.
The word “population” It comes from the Latin population“crew”and this one from populuswhich meant “people” or “citizenship”. Today, populations are the subject of various studies and different analytical perspectives, which attempt to identify the trends in the formation, development and growth of communities of our species.
See also: Rural and urban population
Concept of population
The concept of population varies depending on the specific disciplineFor example, for demography, a population is a stable and constituted set of individuals, linked to each other by dynamics of reproduction and by a sense of identity in the territorial, cultural, religious, political, ethnic and/or legal aspects.
However, for biology, ecology or sociology, a population is nothing more than a set of individuals who share a specific geographythus being able to speak of human populations, populations of red foxes or microorganisms.
In the case of statistics the concept becomes even more abstract: a population will be a certain set of elements of which a portion will be subjected to scrutiny or study.
Types of population
In principle, one can distinguish between human populations and animal populations or plant populations, depending on the nature of the individuals to be studied. In this sense, there would be as many types of populations as there are categories of the same.
On the other hand, populations can be classified as follows, according to their biological considerations:
- Family populations. Those in which individuals are united by a bond of consanguinity or kinship.
- Gregarious populations. Those formed by groups of individuals not necessarily related, but who share some type of group movement, whether for migratory, defensive or predatory purposes: prides of lions, schools of fish, packs of dogs, etc.
- State populations. Those characterized by hierarchization, specialization and distribution of tasks among their individuals, which makes isolated life possible.
- Colonial populations. Those that form physically united individuals or that share very small spaces, in which they proliferate and in which they generally do not move, such as corals.
Growth and decline
Populations, whatever their type, usually grow (increase in the total number of individuals) or decrease (decrease in the total number of individuals), according to conditions that can be the object of study. They are between them:
- Availability of resources. Populations settled in a place where resources are more available (food, space, etc.) will have an important element in their favor to grow, while those that lack this will grow more slowly or, if the resources have suddenly disappeared, will begin to decrease.
- Survival. If the conditions of a population allow a long life expectancy for its individuals, it is much more likely that they will reproduce more than once and lead their own lives to a successful conclusion, whereas in much more ferocious conditions (wars, famines, etc. .) Populations tend to decrease, since their new individuals do not have time to reproduce.
- Mobility. Populations are not necessarily closed entities, and it is possible for individuals to change populations one or more times in their lives, causing one to grow and the other to decrease: a migrant causes the starting population to decrease, but increases the destination population.
Birth and mortality
Two central rates or tendencies that They establish the growth and decline of populations are the birth of new individuals and their death. These are processes that occur in all populations, as one generation replaces another, but not in the exact same proportion.
To understand this process is on the one hand the concept of Birth rate: the number of individuals born in a certain period. On the other hand, the mortality rate: the number of individuals who die in a given period.
Both figures are compared, and thus we can know what fate awaits the population, for example:
- If the birth rate is much higher than the death rate, the population will grow dramatically.
- If the birth rate is just above the death rate, the population will grow slowly.
- If the birth rate is equal to the death rate, the population will neither increase nor decrease.
- If the death rate is much higher than the birth rate, the population will decrease dramatically.
- If the death rate is just slightly higher than the birth rate, the population will decline slowly.
Population density
Population density (or relative population) is a calculation that averages the number of inhabitants and the available space for them to dwell. To do this, the total number of inhabitants is divided by the surface area of the territory (inhab/km2), which gives a figure that will indicate how densely populated a location is.
If the density is high, the inhabitants have little space for themselvessince there are many of them for the populated space; if on the other hand it is low, they will have a lot of space for themselves, since there are few of them for the populated space.
For example, The city of Buenos Aires has a population density of 14,458.8 inhabitants/km2while the Canadian capital, Ottawa, has a density of 278.6 inhabitants/km2.
Population pyramid
The number of individuals of each sex and age group of a population is commonly represented in a population pyramid, that is, a graph that places the sex groups and number of individuals on an X axis, and age on a Y axis.
So, a joint visualization of the population distribution is obtained Based on their sex (men on the right and women on the left) and age, and depending on the longevity of the population, we can have these types of pyramid:
- Expanding pyramid. A broad base and narrow top indicate a predominance of young people, decreasing in number as they age. This is typical of populations with high birth and death rates.
- Stationary pyramid. With a smaller base and less difference from the top, it indicates a predominant adult population, but with good survival, typical of mature populations with a higher quality of life.
- Regressive pyramid. With a narrow base and more extensive peaks, indicative of a majority old population, the result of low mortality and birth rates, as in populations with reduced growth.
Economic population
The analysis of the populations from an economic point of view shows two types of inhabitants:
- Economically active population. Those inhabitants who are inserted in the productive dynamics, that is, who are in physical and mental conditions to work, even if they are currently vacant. It is also called Working Age Population.
- Economically inactive population. Those inhabitants incapable of employment for various physical or mental reasons. They are also known as the dependent population, since they must be maintained by the active population.
Population censuses
The censuses They are the instrument par excellence to register and know a populationespecially human ones. It is carried out by enumerating the inhabitants and detailing their characteristics, from a social, economic, family, etc. perspective.
All this data is then processed and feed the production of statisticswhich allows drivers and analysts of society to better understand its population trends.
The world population
The total human population is, according to the 2009 census, about 7 billion inhabitants distributed throughout the earth’s surface, in the 194 recognized countries on the planet.
If we consider that in 1804 we were approximately one billion, and that in 1974 we already reached 4 billion, we will see that We are a growing total population, but at an increasingly slower paceIt is estimated that we will reach population equilibrium by 2093, when we will reach 11.5 billion inhabitants.
Examples of population
Examples of population in its various meanings can be the population of common cockroaches that exists in the kilometers of pipes in your city, or Total inhabitants of the neighborhood where do you live.
Population can also be used to refer to: individuals in the electoral register or registrationor those who voted according to one political tendency or another (numerically, since in a democracy the vote must be secret).