ECOLOGICAL RELATIONSHIPS: WHAT THEY CONSIST OF, TYPES AND EXAMPLES - BIOLOGY - 2024

The ecological relationships or biotic interactions are all those interactions that occur between living organisms with their environment and with members of the community to which they belong.

None of the living beings on the planet exist in a totally isolated way; These establish different types of relationships with the environment, with individuals of the same species (intraspecific relationships) and with individuals of different species (interspecific relationships).

Photograph of a bird feeding on the nectar of a flower and participating in its pollination (Image by homecare119 at www.pixabay.com)

Identifying and classifying the way in which living things in an ecosystem are related allows ecologists and other scientists to systematically study these interactions and those who participate in them.

The existence of ecological relationships means that researchers cannot refer to ecosystems and living beings as if they were a flat list with only the names of the different organisms, since species are never found as isolated entities.

In addition, species are "molded" according to the ecological relationships in which they are involved, so they can present "specializations" that allow them to interact in a synchronous and almost perfect way. In other words, these species adapt to the environment that surrounds them and to the other organisms with which they interact.

What are ecological relationships?

Ecological relationships serve to represent the life of species, since no organism, however independent it may seem, can be described in an ecosystem in a totally isolated way.

All species are part of a complex network, typical of each ecosystem. In this network, all individuals depend on each other for their survival, since each node of the network represents in some way an irreplaceable service for the other nodes of the network.

Each individual of a species has many different types of relationships, both with individuals of the same species, and with other species. In addition, the survival of the species depends on the permanence in time of these ecological relationships.

Take the example of a plant species that is pollinated exclusively by a bird species when it feeds on its nectar. If this species of bird disappears or for some reason is prevented from visiting the plant, the plant will most likely disappear.

Types

In the literature, ecological relationships are divided into two groups: intra-specific relationships, which occur between individuals of the same species, and inter-specific relationships, which occur between individuals of different species.

- Intraspecific ecological relationships

This type of interaction includes the direct and indirect relationships that occur between individuals of the same species. These interactions can occur circumstantially or permanently in the lives of individuals and are:

Colonial relations

In this relationship many of the individuals of the same species are held together in a bodily way, since the individuals are produced by budding from a first primitive or primal individual.

The components of the colony can all be the same or they can be specialized to perform specific functions such as feeding, excretion, etc. This type of interaction can also refer to intercolonial associations (between several colonies).

Researchers treat the entire colony as a single individual, since the physiological relationships between them are such that they lose their individuality, so the colony acts and behaves as a single individual.

Sexual association

Individuals of the same species only meet around a procreative purpose, the relationship can end just after the act of sexual reproduction. In some species, the interaction between individuals is maintained during the birth and rearing period of the offspring.

In others, these associations occur en masse. These can be so ephemeral that they are able to end just after the release of the sex cells to the environment or, in other cases, they can remain throughout the rearing period of the offspring.

Asexual associations

Asexual associations can have a number of goals other than procreation. These can be for food, protection, migration or hunting purposes. They are classified into two types:

Gregarious: multiple individuals of the same species are grouped and aligned for nutritional and defensive purposes, but without reaching a synchrony or a high level of organization in the general activity of the individuals.

State: they compose a type of relationship in which there is a complex degree of organization and distribution of the tasks necessary for the survival of the population. Different classes can appear within the population, separated by morphological and physiological characteristics.

Within these associations are the states, peoples and “eusocieties” observed in the different species of animals. Due to state relations, territoriality occurs between populations and individuals.

- Interspecific ecological relationships

Here all the interactions that occur between individuals of different species are classified, whether permanent, temporary, direct or indirect. Among the inter-specific relationships are:

Commensalism

In these relationships the diner lives on or within the host's body and feeds on the host's leftovers or offal. These are denoted by the symbols (0, +).

Predation

Individuals of one species feed on individuals of another, and the hunter can cause serious harm (or death) to the individual that serves as food or prey. It is represented by the symbols (-, +).

Amensalism

It is considered a type of asymmetric symbiosis in which one of the species is harmed and the other does not obtain any benefit. It is represented by the symbols (-, 0).

Competition

Both species compete for a resource available in the environment, therefore, the result is a difficulty in obtaining the resource. It is represented by the symbols (-, -)

Symbiosis

It constitutes the relationship of two organizations for mutual benefit. It can be represented by the symbols (+, +).

Parasitism

The relationship between two species where one of them feeds on the other. In this interaction, the parasite causes some damage to the species it parasitizes. It is represented by the symbols (+, -).

Examples

Intraspecific relationships

Corals are organisms that form very large colonies of different individuals. It is really difficult to identify where each individual who comprises the colony begins and ends.

Some species of fish and marine animals only meet with the female individuals of their species when it is the reproductive season. These gather for the time of fertilization and then separate until the next breeding season.

Photograph of a school of sardines (Image by pixaoppa at www.pixabay.com)

Gregarious relationships develop in sardine schools or herds of large herbivores, as they usually come together to defend themselves effectively from predators. Sometimes these groups follow, by a principle of subordination, the more experienced males.

Eusocial behavior of bees (Image by PollyDot at www.pixabay.com)

Eusocial insects such as bees, ants, and wasps have very complex state relationships. The hives and colonies are organized in different castes, with specialized morphologies for the function that each individual fulfills.

Interspecific relationships

A classic example of commensalism is the bacteria in the digestive tract of vertebrate animals, since they feed on the food consumed by the animal, but without affecting or harming its life.

The symbiosis that is created between green algae and some fungi originates lichens. The algae synthesizes organic matter that the fungus can assimilate for its subsistence, while the fungus provides the algae with hydration and salts necessary for its survival.

Lions feeding after the hunt (Image by MonikaP at www.pixabay.com)

Among the famous examples of predation is the lion's pursuit of gazelles in the African savannah. Lions hunt gazelles for their nutritional needs, trap them, kill them, and end up devouring them.

Parasitism can be observed among all plant species, since all plants interact with bacteria and fungi that help them transform certain nutrients from the substrates into assimilable forms for their metabolisms.

References

1. Appel, HM (1993). Phenolics in ecological interactions: the importance of oxidation. Journal of Chemical Ecology, 19 (7), 1521-1552.
2. Bronstein, JL (1994). Our current understanding of mutualism. The Quarterly Review of Biology, 69 (1), 31-51.
3. Bunwong, K. (2011). Numerical Simulation on Ecological Interactions in Time and Space. Numerical Analysis: Theory and Application, 121.
4. Glavič, P., & Lukman, R. (2007). Review of sustainability terms and their definitions. Journal of cleaner production, 15 (18), 1875-1885.
5. Vera-Licona, P., & Laubenbacher, R. (2008, October). Inference of ecological interaction networks. In Annales Zoologici Fennici (Vol. 45, No. 5, pp. 459-465). Finnish Zoological and Botanical Publishing Board.