If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Main content

Competitive, predatory, and mutualistic interactions

Review your understanding of competitive, predatory, and mutualistic interactions in this free article aligned to NGSS standards.

Key points:

  • Across all ecosystems, organisms interact in specific ways.
    • Competitive interactions happen when organisms compete for the same set of resources.
    • Predatory interactions happen when one organism hunts and eats another organism. The organism doing the eating is a predator. The organism being eaten is the prey.
    • Mutualistic interactions happen when two organisms of different species benefit from interacting with each other. In some cases, organisms in a mutualistic relationship even require each other for survival.
Two carpenter ants are on a plant stem along with multiple scale insects.
Carpenter ants and scale insects can have a mutualistic relationship. The ants get food from a sugary liquid given off by the scale insects. The scale insects get protection from the ants. Image credit: “Guardians" by Bob Peterson, CC BY-SA 2.0.

Want to join the conversation?