13-4 How do living things interact?
Aim: How do living things interact?
OBJECTIVE: Explain how interactions between living things help maintain balance in an ecosystem.
Key Terms
competition: struggle among organisms for resources in an ecosystem
predation: relationship in which an organism kills and eats another organism
predator: organism that kills and eats another organism
prey: organism that is killed and eaten by another organism
Lesson Summary
• Organisms in an environment interact and compete for resources.
• Animals may compete with members of the same species or with different species.
• Animals that are better adapted to conditions in the habitat are more likely to survive and reproduce.
• Plants also compete for resources such as sunlight and water.
• Predation is a relationship in which one organism kills and eats another organism. An animal that
kills and eats another organism is called a predator.
• An organism that is killed is called the prey.
OBJECTIVE: Explain how interactions between living things help maintain balance in an ecosystem.
Key Terms
competition: struggle among organisms for resources in an ecosystem
predation: relationship in which an organism kills and eats another organism
predator: organism that kills and eats another organism
prey: organism that is killed and eaten by another organism
Lesson Summary
• Organisms in an environment interact and compete for resources.
• Animals may compete with members of the same species or with different species.
• Animals that are better adapted to conditions in the habitat are more likely to survive and reproduce.
• Plants also compete for resources such as sunlight and water.
• Predation is a relationship in which one organism kills and eats another organism. An animal that
kills and eats another organism is called a predator.
• An organism that is killed is called the prey.