1 of 9

Interactions �Between Organisms

Lesson 2

2 of 9

Interactions Between Organisms

COMPETITION

PREDATION

MUTUALISM

PARASITISM

organisms interact in a variety of ways

MRSTAV

3 of 9

1) COMPETITION : Interactions Among Living Things

  • competition occurs when more than one organism tries to obtain the same basic resources in the same habitat
    • example: plants in the same meadow are competing for:
      • the same nutrients in the soil
      • the same water
      • the same sunlight
  • if some of the plants die, the remaining ones have better access to the resources

​

MRSTAV

"the plant hunger games”

- Younge 2021

MRSTAV

4 of 9

2) PREDATION : Interactions Among Living Things

  • predators are animals that hunt other animals for food
  • prey are the animals that are being hunted�

MRSTAV

5 of 9

2) PREDATION : Interactions Among Living Things

  • the populations of the predators and prey are closely connected and create a cycle

POPULATION

    • when the population of prey becomes high, there is more food available for the predators to eat
    • this causes the population of the predators to increase
    • when there are more predators to hunt, the population of the prey falls
    • fewer prey mean that there is not enough to eat and the population of the predators falls

MRSTAV

6 of 9

2) PREDATION : Interactions Among Living Things

Figure 1: The predator-prey cycle of the snowshoe rabbit and the lynx.

(PREY)

(PREDATOR)

MRSTAV

7 of 9

3) MUTUALISM : Interactions Among Living Things

  • mutualism is an interaction between individuals of different species in which both benefit
    • EXAMPLE: When a bee visits a flower, the bee gets to eat the nectar and the flower’s pollen attaches to the hairy back of the bee. When the bee visits a different flower, the pollen transfers and the new flower is fertilized.

MRSTAV

8 of 9

4) PARASITISM : Interactions Among Living Things

  • parasitism is an interaction between individuals of different species in which one benefits and the other is harmed
    • EXAMPLE: When a tapeworm lives in the intestine of an animal, the tapeworm steals the nutrients that the animal eats.
      • The tapeworm benefits because it gets food
      • but the animal is harmed because it has less to eat.

​

MRSTAV

9 of 9

Interactions Between Organisms

COMPETITION

PREDATION

MUTUALISM

PARASITISM

organisms interact in a variety of ways

MRSTAV