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different types of interactions with example.
 Relationships between members of an ecological community can be classified within two broad categories, direct effects and indirect effects. The first of these, direct effects, as the name implies, deals with the direct impact of one individual on another when not mediated or transmitted through a third individual. If you have ever watched a cheetah capture a gazelle or a bee pollinate a flower, then you have observed a direct effect in action. There are eight main types of direct effects which are classified by the net effect of the relationship on each individual; positive, negative, or neutral .

Competition: Competition occurs when two organisms compete for the same resource (food, space, mates, etc.). Both individuals are negatively impacted by competition for the resource because either the resource is limited or, if the resource is not limited, they can physically interfere with competitors attempting to obtain the resource.

Predation: Predation takes place when one organism (the predator) consumes another (the prey). Typically, carnivores, such as the cheetah pursuing the gazelle mentioned above, are excellent examples of predation. In its broadest sense, the term predation includes all consumption of another organism for nutrients, including herbivory and parasitism. However, as the latter have some unique characteristics, they are often considered independently of predation.

Herbivory: When a plant is eaten by another organism, it is considered herbivory. Unlike predation, in which the whole organism is destroyed, plants often survive grazing by an herbivore. For this reason, herbivory is sometimes referred to as plant parasitism.

Parasitism: A parasite is physiologically dependent upon its host for nutrition. While the host is negatively affected by the loss of nutrients to the parasite, parasitism rarely leads directly to the host's death. Unfortunately, humans are hosts to any number of parasites, including liver flukes, tapeworms, lice, pinworms, giardia, and many others.

Mutualism: In a mutualism, both partners benefit from the relationship. Many coral reefs have "cleaning stations" where some species of fish remove parasites from other fish. The cleaner fish get nutrition from the consumed parasites while the cleaned fish enjoy freedom from their parasites.

Commensalism: Commensalism occurs when one organism is positively affected by the relationship while the other organism is not affected, either negatively or positively, by the interaction. Cattle egrets who feed on the insects stirred up by domesticated cattle are an example of commensalism. Some birds have even taken advantage of the invention of the lawn mower to extend this relationship to the suburban lawn.

Amensalis: Amensalism takes place when one individual is negatively affected by interaction with another individual who is not affected by the relationship. Many molds, including Penicillium, secrete chemicals that kill bacteria in their vicinity.

Neutralism: Interactions between the two individuals are neutral in regards to both species. Some bacteria may exhibit neutralism as it has been reported that some species of Lactobacillus and Streptococcus can coexist without affecting each other positively or negatively. However, it has been suggested that true neutralism is probably rare in nature.


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