Ecological Community: Networks of Interacting Species

An ecological community is defined as a group species that inhabit the same place and interact with each other in various combinations. In ecology, communities are the biotic components of an environment, including its Archaebacteria, Eubacteria, Fungi, Protista, Plantae and Animalia, these are the six known kingdoms of Earth’s biosphere. The organisms that share a close genetic heritage and/or can potentially interbreed to create offspring are generally considered to be of the same species.

Groups of species that inhabit the same area are referred to as populations; ecological communities consist of all the interconnections among species’ populations. Just like the abiotic factors in an environment – like weather or availability of water – species interactions contribute to natural selection pressures. Natural selection determines which organisms live long enough to reproduce and which do not. Interactions shape the environment and the evolution of species through time.

Community ecology as a discipline seeks to answer questions about how species interact and what drives their patterns of diversity and distribution. The ways in which species interact can range greatly. Species exchange nutrients, consume one another, compete for resources like sunlight and space, and help each other out in some cases. There are five main types of interactions between species: competition, predationmutualismcommensalism and parasitism. These labels are known as interspecific interactions, and they represent how species are affected by other species that they deal with.

Some interactions result in benefits for one species group, and disadvantage the other interacting species group. This interspecific interaction can fit into the parasitism category or the predation category. Interactions of this sort can be simplified as (+/-); the “+” represents the benefit for one species while “-” refers to the detriment to the other. Other interactions can produce mutual benefits for both species, (+,+). In cases like these, its not uncommon for there to be a sort of coevolution at work, where both species have evolved specific adaptations to facilitate the services that they provide while also benefiting themselves. We can apply + and – to further depict how species are affected or unaffected by their relationships to one another: competition (-/-), predation (+/-), mutualism, (+/+), parasitism (+/-), and commensalism (+/0). Commensalism is an example in which one species gains some benefit while the other species loses nothing but also gains nothing.

Competition

Competition (-,-) is an interaction in which organisms of two or more species use the same resource. Any given resource will be limited, and may have significant costs for either of the organisms involved.

Predation

Predation (+,-) is an interaction that involves one species eats (and in some cases also hunts) another (the latter species is often called prey). Some ecologist extend the term predation to include herbivorous consumption. This is because the general principle at play is one species is consuming another.

Commensalism

Commensalism (+/0) is an interaction in which organisms from one species are able to benefit at no cost to the other species that it is interacting with.

Parasatism

Parasitism (+,-) is characterized by the benefit of one species at some cost or harm to members of the a targeted species. Its common for parasitic organisms to live inside, or otherwise attach themselves to the targeted organisms (sometimes called hosts).

Mutualism

Mutualism (+,+) occurs when both of the involved species benefit from the interaction, which may motivate a long term association between them. We explore an example of this type of interspecific interaction below.

Ecological Community Interaction Example

The relationship between pollinators and plants is a classic example of a mutualistic relationship (+,+) that is rooted in a long and intimate coevolutionary relationship. Pollinators visit flow after flower to collect pollen and other nectars which the pollinator uses as food. Bees are a classic example pollinators. Bees, like other pollinators benefit by feeding on nectars and pollens for nutrients. Plants benefit by having their pollen efficiently distributed to other flowers of the same species, this is one way in which flowers pollinate, another way is by wind carrying pollens between male and female flowers. Pollination plays an essential role in plant reproduction. Once a female part of a flower (stigma) receives pollen from a male portion (anthers), fertilization can take place.

bee pollinating white flowers
bee pollinating white flowers

Don’t forget to check us out on Twitter!

Leave a Reply