Ecosystem Interactions and Symbiosis

Study Notes

Students will use a science probe to assess prior knowledge on relationships between organisms.
The activity, "What's the relationship?" will help uncover student preconceptions through a formative assessment.
Students will investigate a cleaner shrimp and a moray eel relationship.

Symbiosis is a close, long-term relationship between species, often involving an exchange of food or energy.
Symbiotic relationships form when organisms live in direct contact.
Some species have extremely close relationships, always living together.
Barbel fish and hippos have a symbiotic relationship: the fish follow and groom the hippos to eat parasites and then are rewarded with food scraps in return.

Commensalism: One species benefits while the other is neither harmed nor helped. An example is epiphytic plants growing on trees, receiving sunlight, while the trees are unaffected.
Parasitism: One species benefits (the parasite) while the other is harmed (the host). An example is the hunting wasp larvae that lay eggs in a spider, eating it after hatching.
Mutualism: Both species benefit from the interaction. An example is clownfish and sea anemones living together: the clownfish receive protection from predators and the anemone receives nutrients from the clownfish's waste.

Cooperative Relationships: Organisms cooperate to help each other, like elephants raising their young and watching for predators, or squirrel monkeys cooperating in groups when hunting for food or watching for danger.
Predator-Prey Relationships: One organism (predator) eats another (prey). An example is an osprey catching a fish, which helps keep prey populations healthy and in check.
Competitive Relationships: Organisms compete for the same resources like sunlight (trees) or food (wolves and ravens).