Symbiotic Relationships

Community Interactions O When organisms live together in ecological communities, they interact constantly. These interactions help shape the ecosystem in which they live.

Competition-organisms of same or different species use the same resources at the same place and time O Both organisms are harmed

Which two organisms compete for the same food?

Predation-interaction in which one organism catches and eats another organism O One organism benefits the other is dead

Symbiosis-Any relationship in which two species live closely together O Types of Symbiosis O Mutualism O Commensalism O Parasitism

Mutualism-both species benefit from the relationship

Commensalism-One species benefits the other is neither helped nor harmed

Parasitism-One organism benefits the other is harmed

Lets Test Your Knowledge

Scenario 1 O A wasp lays its eggs inside a tomato hornworm caterpillar. When the wasp larvae hatch they use the caterpillar tissue for food O Which relationship is it?

Scenario 2 O A squid emits light that can hide it from predators. The light is actually produced by bacteria living in part of the squid’s body called a light organ. The squid provides nourishment for the bacteria throughout its life. O What type of relationship is it?

Scenario 3 O Acacia tree ants live in acacia trees in South America. Ants guard their tree from other insects, and even cut away other plants that may compete with the acacia. The acacia tree provides food and shelter for the ants O What type of relationship is this?

Scenario 5 O After people eat coconuts, the coconut shells are discarded. Some of these discarded shells in Indonesia are picked up by a species of octopus. The octopi use the shells for shelter and protection. O What type of relationship is this?

Scenario 6 O Shark attacks a seal O What relationship is this

Writing Activity O How are the three types of symbiotic relationships different? Similar? O Mutualism O Commensalism O Parasitism