The term ecology was originally used by Ernst Haeckel (1834-1919), in 1866, in the work Generelle morphologie. The word ecology is derived from two Greek words: oikós and logos , which mean, respectively, “house” and “study”. We can conclude, therefore, that ecology would be the study of the place where living beings live, however, this part of biology is much more complex. A better way to define ecology would be:
Ecology has two subdivisions: autoecology and synecology. In autoecology, the object of study is the individual or a given species, in which case, for example, studying how the environment can influence the behavior, physiology and morphology of a given species. Synecology , in turn, studies communities, observing not just one species, but different organisms and how they associate.
Levels of organization
When we study biology, the division into hierarchical levels is important to facilitate the study. This division usually has 12 levels: atom , molecule, organelle , cell , tissue , organ , system, organism, population, community , ecosystem and biosphere .
In ecology, an organism will not be analyzed at all of these levels, some of which are unique to other areas of biology. In ecology, the levels of organization addressed are: organism, populations, communities, ecosystems and biosphere.
- Organism: is an individual of a particular species.
- Population: is a term used to refer to individuals of the same species, who live in a certain place and at a certain time. In a population, genetic material is exchanged between individuals.
- Community: is a term used to refer to the set of populations that live in a certain area and at a certain time. In a community, individuals of different species interact with each other.
- Ecosystem: refers to the set formed by the abiotic (lifeless) and biotic (living beings) components of a region. These two components interact with each other and ensure that energy flows and matter is recycled.
- Biosphere: set of all ecosystems on the planet, that is, all regions of the Earth where there are living beings.
Basic concepts of ecology
To study ecology, it is important to have knowledge of some basic concepts. In addition to those already studied when we talk about levels of organization, the following are important concepts:
- Habitat : where a particular species lives. The zebra lives in the African savannah, which is therefore its habitat.
- Ecological niche : is the way of life of a given organism.
- Ecological pyramid : is the graphic representation that reproduces the different trophic levels of an ecosystem. Ecological pyramids can be of three types: number, biomass and energy.
- Ecological relationships : are the interactions established between living beings. Ecological relationships can be intraspecific, when they involve individuals of the same species, and interspecific, when they occur between individuals of different species. Ecological relationships can also be classified into harmonious and disharmonious, considering the benefits and harms arising from the interaction.
- Food chain : linear sequence by which matter and energy are transferred from one trophic level to another. The food chain shows a sequence of living beings that serve as food for others, starting with the producing organisms.
- Food Web : A collection of interconnected food chains. In food webs, the same organism can be at different trophic levels.
- Trophic level : set of organisms in an ecosystem that have the same type of nutrition. All organisms that carry out photosynthesis , for example, occupy the same trophic level: the producers. There are three main trophic levels: producers, consumers and decomposers.
- Producers: these are autotrophic organisms , that is, those capable of synthesizing their own food. Plants and algae are producer organisms.
- Consumers: are those heterotrophic organisms, unable to synthesize their own food, and therefore need to ingest other living beings. Primary consumers feed on producers, secondary consumers feed on primary consumers, tertiary consumers feed on secondary consumers, and so on.
- Decomposers: are organisms that carry out decomposition , a process through which they obtain the nutrients they need from dead matter, and promote the return of some chemical compounds to the environment.
Branches of Ecology Studies
Ecology is a very broad area of biology, therefore, it has many branches of specific studies that are difficult to be fully delimited.
Although divided into animal ecology and plant ecology, plant ecologists need to know a little about animal ecology and vice versa.
Among the most popular categories we have:
- Autoecology : is the classic study of ecology, which experimentally analyzes the relationships between an organism and its environment;
- Synecology : study of communities. It is more philosophical and descriptive and can be divided into terrestrial and aquatic, which can be subdivided. For example: aquatic ecology encompasses limnology (ecology of watercourses) and marine ecology (study of estuaries and open ocean);
- Demoecology : studies the dynamics of populations, that is, it analyzes how species richness varies and why this happens;
- Human Ecology : studies the relationships between individuals and different human groups. It analyzes situations such as diseases, epidemics, public health and environmental quality problems.