Species Interactions

Miller 8-3

Five basic types of interactions

• Interspecific competition

• Predation• Parasitism• Mutualism• Commensalism

Competition

• Between members of the same species for resources such as food, water and shelter.

• Often solved by establishing territories

Grey Wolf – large territory

House Wren – small territory

Interspecific competition

• Competition between different species for one or more resources

• Often these species are very much alike – they occupy similar niches

• Competitive Exclusion Principle – niches can not overlap completely or for very long

House Wren

Bewick’s Wren

Predator – Prey Interactions

• Members of one species (predator) feed directly on members of another species (prey)

• Often beneficial to the prey species.

How do predators increase their chances of getting prey?

• Pursuit – adaptations that allow the running down of prey. Fast, good eyesight, hunting cooperatively

• Ambush – hide and ambush. Camouflage

How do prey defend themselves?

• Move fast• See or smell well• Protective shells• Thick bark• Spines• Camouflage• Chemical warfare

Coral snake (poisonous) and milk snake

Snake caterpillar

Canyon tree frog

Clown Fish is not bothered by stinging cells of Anemone. It gets it’s food as leftovers from the Anemone. The clown fish protects the anemone from predators

Symbiosis

• Long term relationship of two species living together

• Three types– Parasitism– Mutualism– Commensalism

Mutualism

• Both species benefit from the interaction

Lichen – Fungus provides attachment to the rock or tree and algae does photosynthesis to make food for both

Commensalism

• Benefits one species, but does not benefit or harm the other species

Orchids are epiphytes

Parasitism

• When one species (parasite) feeds on part of another species (host)

• One benefits and one is harmed