Interactions in Ecosystems

There are many ways to describe an organism's behavior and needs in an ecosystem. Here are some of the most basic terms that refer to how the organisms receive their nutrients:

Producer: organism that produces its own food through photosynthesis

Consumer: organism that somehow obtains and ingests its food from the environment

• Herbivores: plant/algae eaters
• Carnivores: animal eaters
• Omnivores: eats both plant and animal matter

Decomposer: organism that causes organic material in the environment to decay in order to absorb its nutrients, also known as a Saprophyte or Saprobe.

Each organism in a community occupies a niche, a term that refers to everything that organism contributes to the system. Examples of activities that make up an organism's niche include what it consumes, what consumes it, how it alters the habitat, and what wastes it produces. Organisms that live in the same community adapt to each other and rely on each other to fill these niches.

When a niche does not get filled due to migration or local extinction, then other organisms are threatened. The more diverse a community, the more the species will be able to withstand the loss of a species. Here are some examples of how organisms interact and thus rely on each other.

Competition

Within ecosystems of any kind, from forests to open plains to coral reefs, some of the resources that support survival and growth are finite (limited). Food is the most common category of limiting resource, followed by space. Space can be in the form of territories (which are often also about access to food), or just uncrowded physical living space.

Access to sunlight is important for plants, such as in forests with canopies that block out sunlight from reaching the ground. Within a species, there's also access to mates, for example, male African lions taking over prides from other males.

Competition occurs when many organisms within an ecosystem want to use the same resources and there isn't enough to go around. Variation among organisms allows some to be more successful than others. Those organisms survive and reproduce and pass their adaptations along to their offspring.