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14.2 Community Interactions
OBJECTIVES
Students will learn that
competition and predation are
two important ways that
organisms interact AND that
symbiosis is a close
relationship between species.
14.2 Community Interactions
KEY CONCEPT
Organisms interact as individuals and as populations.
14.2 Community Interactions
Competition occurs when two organisms fight for the same
limited resource.
Intraspecific competition:
2 of the same species
compete for a resource
Ex: 2 tigers fighting for a
kill or a mate
14.2 Community Interactions
Interspecific competition: 2 different species fighting over the same
resources
Ex: A lion and a hyena fighting over a kill
14.2 Community Interactions
• Predation occurs when one organism captures and eats
another.
14.2 Community Interactions
• There are three major types of symbiotic relationships.
1) Mutualism: both organisms benefit
Bat and Saguaro cactus
Egyptian Plover and crocodile
14.2 Community Interactions
2) Commensalism: one organism benefits, the other is
unharmed
Ex: Cattle EgretThe cattle disturb
insects as they
graze, making it
easy for Egrets to
find their meals
14.2 Community Interactions
3) Parasitism: one organism benefits, the other is harmed
– ectoparasites (such as leeches) live on the outside
of the body
– endoparasites (such as hookworms) live inside the
body