Interactions Within Interactions Within EcosystemsEcosystems

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Competition

• Competition is the struggle between organisms to survive in a habitat with limited resources.

• One species may die off if it cannot get the resources it needs

• Organisms that survive have adaptations that enable them to reduce competition – eating different food, living in a different place etc.

Predation

• Predation is an interaction in which one organism hunts and kills another for food.

• The predator is the organism that does the killing

• The prey is the victim; the organism that gets caught

Predator Adaptations

• Some species have adaptations that can help them catch and kill their prey – cheetah can run fast, jellyfish’s tentacles can paralyze tiny animals

Prey Adaptations

• An organism’s physical characteristics can help protect it from getting eaten

Symbiosis

• Symbiosis is a close relationship between two species that benefits at least one of the species

• There are three types of symbiotic relationships:– Mutualism– Commensalism– Parasitism

Mutualism

• Mutualism is a relationship in which both species benefit

• Saguaro and long-eared bats

Commensalism

• Commensalism is a relationship in which one species benefits and the other is neither helped nor harmed

• Red-tailed hawks and saguaro

Parasitism

• Parasitism involves one organism living on or inside another organism and harming it

• The organism that benefits is called a parasite

• The organism that lives on or in is called a host

• Tapeworms living in a dog