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Biology LibreTexts

6. 14: Competition

Does there have to be a winner?

When animals compete? Yes. Animals, or other organisms, will compete when both want the same thing. One must "lose" so the winner can have the resource. But competition doesn't necessarily involve physical altercations.

Competition

Competition is a relationship between organisms that strive for the same resources in the same place. The resources might be food, water, or space. There are two different types of competition:

  1. Intraspecific competition occurs between members of the same species. For example, two male birds of the same species might compete for mates in the same area. This type of competition is a basic factor in natural selection. It leads to the evolution of better adaptations within a species.
  2. Interspecific competition occurs between members of different species. For example, predators of different species might compete for the same prey.

Interspecific Competition and Extinction

Interspecific competition often leads to extinction. The species that is less well adapted may get fewer of the resources that both species need. As a result, members of that species are less likely to survive, and the species may go extinct.

Interspecific Competition and Specialization

Instead of extinction, interspecific competition may lead to greater specialization. Specialization occurs when competing species evolve different adaptations. For example, they may evolve adaptations that allow them to use different food sources. Figure below describes an example.

Specialization lets ground anoles and tree anoles live together without competing

Specialization lets different species of anole lizards live in the same area without competing.

Watch the beginning of the following video to learn more about competition.

Summary

  • Competition is a relationship between organisms that strive for the same resources in the same place.
  • Intraspecific competition occurs between members of the same species. It improves the species’ adaptations.
  • Interspecific competition occurs between members of different species. It may lead to one species going extinct or both becoming more specialized.

Review

  1. What is competition?
  2. Describe the evolutionary effects of intraspecific and interspecific competition.