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Community Interactions. Community Interactions. Community : Many different species interacting in the same environment. Three types of interactions: Competition Predation Symbiosis. Competition. Defined : Competing for resources Water, nutrients, light, food, space
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Community Interactions • Community: Many different species interacting in the same environment. • Three types of interactions: • Competition • Predation • Symbiosis
Competition • Defined: Competing for resources • Water, nutrients, light, food, space • Occurs due to a limited number of resources • Intraspecific competition: When organisms of the same species compete for resources. • Interspecific competition: When organisms of differing species compete for resources. • Competitive exclusion principle: No two species can occupy the same niche in the same habitat at the same time. • Example: What happens to the neighborhood coffee shop when a Starbucks is built next to it?
Predation • Defined: when an organism captures and feeds on another organism. • Predator = hunter • Prey = hunted
Symbiosis • Defined:arelationship between two or more species that live in direct contact with one another. • Three types • Mutualism • Commensalism • Parasitism
Mutualism Fungus obtains nutrients from the algae Fish receives protection and a home • Defined: both species benefit from a relationship. • Ex: Lichens (fungus and Algae) • Ex: Clown fish and anemones • Ex: Cleaner birds and crocodiles Algae lives amongst the fungal cells Anemone feeds on undigested food from the fish Bird receives food Crocodile has parasites removed
Commensalism • Defined: One member of a symbiotic relationship benefits and the other is neither helped nor harmed • Ex: Cattle and Birds • Birds eat insects stirred up by the cattle • Ex: Barnacles and whales • Barnacles grow on whale
Commensalism Human Our eyelashes are home to tiny mites that feast on oil secretions and dead skin. Without harming us, up to 20 mites may be living in one eyelash follicle. Ø Demodicids Eyelash mites find all they need to survive in the tiny follicles of eyelashes. Magnified here 225 times, these creatures measure 0.4 mm in length and can be seen only with a microscope. + Ø + Organism is not affected Organism benefits
Parasitism • Defined: One creature benefits and one creature (the host) is harmed • Endoparasitism: A parasite that inhabits the inside of an organism. • Ex: Tapeworm feeds within a human’s intestines absorbing his/her nutrients • Ectoparasitism: A parasite that inhabits the outside of an organism. • Ex: A leech feeds on the blood of an organism from a host’s skin.
Review • What is a community? • Name the 3 types if community interactions. • When do organisms usually compete? • How do predators and prey interact? • Name the 3 types of symbiosis. • What is the competitive exclusion principle? • How does mutualism, commensalism, and parasitism differ? • How is predation and parasitism differ?