Population and community are important concepts of Ecology that refer, respectively, to the set of individuals of the same species and to a set of populations.
In Ecology , we study the relationships of living beings with each other and with the environment in which they live. These studies correspond to different levels of organization. We can, for example, study only the interactions between individuals of the same species or, even, study their relationships with different organisms. For this, however, it is essential to understand the concepts of population and community.
A population, in Ecology, can be defined as a set of individuals of the same species that live in a given area in a given period of time . Individuals in one population are more likely to interbreed with each other than with organisms in another population of the same species.
Births and immigration (the arrival of new individuals) are factors that increase a population . On the other hand, population density decreases when deaths or emigration (the departure of individuals from that population) occur.
Populations can vary in size, but they do not show continuous and unlimited growth. If a population grows too large, it can affect all organisms in the group and thus limit resources, make reproduction difficult, and reduce the area where individuals live. We say that these factors are natural barriers necessary to prevent an exaggerated growth and, in this way, keep the population always in a limited number of individuals. The maximum size of a population in a natural environment is called the limiting capacity.
As an example of population, we can mention the groups of alligators found in the Pantanal . All alligators are of the same species, relate to each other and live in a certain area. Other examples of population are the lions in the African savannah or the people who live in a certain municipality.
The group of all living beings existing in an area, such as the Pantanal, is called a community.
A community is the group of different populations that live in the same place in a certain period of time. These populations of a community interact with each other through ecological relationships , which can be positive , that is, bring benefits to those involved, or negative , that is, cause harm to at least one of those involved.
Considering the Pantanal as an example, we can verify communities formed by caimans, capybaras, tuiuiús, other species of animals and some of plants. All these organisms are found in the same area and are related to each other and, therefore, form a complex community.