Population in Biology (Meaning and Explanation)

We explain what population is in biology and examples. Individual and community, population density and population growth.

Shoal — The same species can have several populations, each in a certain area.

What is population in biology?

In biology, population or biological population is understood as the set of organisms of the same species (animal, plant, etc.) that coexist in space and time and that share biological properties. The latter implies that the group presents a high reproductive and ecological cohesion, that is, that individuals exchange genetic material (that is, reproduce with each other) and share interactions and requirements for survival.

It is also common to call population a group of organisms that only interbreed (reproduce) with each other due to environmental isolation conditions or similar, since they would be perfectly capable of reproducing with some other foreign member of their species. This use is specific to genetics and evolution.

The same species can have several populations each one in a specific area that serves as its habitat. These can exist completely autonomously and independently, or they can merge or divide according to their environment and the survival needs that arise. Thus, populations can grow, decrease, migrate or even spread among other local populations, which are called metapopulations.

The branch of biology that deals with researching and studying populations is precisely population biology. According to her, we can speak of various types of biological populations, which are:

Family populations Those in which the kinship bond is central and common among the individuals that constitute them, that is, they are all family.
Gregarious populations Those formed by the massive displacement of individuals, who do not need to be related, but rather come together for reasons of security and economy of resources.
State populations Those whose members present a high degree of diversification and specialization, dividing up tasks and not being able to live in an isolated and individual manner.
Colonial populations Those made up of individuals that come from a more primitive one, to which they are physically united, constituting a network or colony of very similar organisms.

Examples of populations

Lion pride - population — A family population is made up of the male, the female and numerous offspring.

Some simple examples of the four types of population above would be the following:

Family population A pride of lions, composed first of all of the male and the female who have numerous offspring, and which in many cases can be made up of several females and a dominant male. The human family could also be an example of this.
Gregarious population Schools of fish, to which individuals are added regardless of their affiliation or genetic origin, moving together, eating together and guaranteeing better chances of survival than being alone.
State population The ideal example of this is a hive of ants, within which numerous individuals coexist, each one endowed with very specific functions: workers, soldiers, fertilizing males and a queen who lays the eggs. None of them can live separately.
Colonial population A good example is the coral populations at the bottom of the sea, where they spread slowly and extend their colony on the seabed or on stones, sharing the same body mass between individuals.

Individual and community

Every living being, of any species, constitutes an individual. As such, it is unique in many aspects, it has a singular and unrepeatable existence, and a genetic code that reflects it. However, in most cases living beings prefer to live among peers, that is, as part of a specific population that, in turn, lives within an ecological community.

So, yes Biological populations are groups of individuals of the same species that share their habitat and usually reproduce among themselves, a community, on the other hand, is the set of populations of different species that share the same habitat. That is, the sum of the populations of the same habitat forms a specific community, in which intra- and extra-species interactions occur that determine a trophic chain.

Population density

The density of a biological population has to do with how concentrated the individuals that make it up are in the specific area of their habitat. That is, how tightly they live, to put it simply. This is usually measured in individuals per unit area, for example, individuals per square kilometer, and is an average, an approximation to understand how close individuals in a population are to each other.

Thus, when the population density is low, that is, few individuals per square kilometer, there will be a lot of surface area between one individual and another, making it more difficult to find them. Instead, When the population density is high, it will be easier to get an individual and they will be closer to each other, since there will be more in the same unit of space.

Population growth

Population growth is understood as increase or decrease in the total number of individuals in a population at a given time. Populations grow when the number of births (birth rate) exceeds the number of deaths (mortality rate), or when they receive migrations of individuals from other populations. And similarly, populations decrease when the number of deaths exceeds the number of births, or when a number of individuals migrate to some other population. In those cases in which the birth rate and the death rate are comparable, it will be said to have a growth equal to zero, that is, it neither increases nor decreases, it remains stable.

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