Competition is a relationship between organisms that compete or strive for the same resources in the same place and at the same time. This kind of relationship can exist among organisms of the same species (Intraspecific Competition). It can also occur among organisms from different species (Interspecific Competition).

Competition among organisms could be for food, water, space, or mates at the same time and place. This can result in a conflict, forcing the weaker organism or the organism with less adaptation to suffer, leave, or become extinct.

One example of a competition relationship is the fight for sunlight and water in a location with a dense tree or plant population. Taller trees get more sunlight and starve low-level plants of sunlight. The result is that the lower level trees do not do as well as the dominant, taller trees.

Other examples of two organisms competing include male birds of the same species competing for a mate. Sometimes, this can end in a fight, and the winner wins the mate.