11-3: SPECIES
INTERACTIONS
(SYMBIOSIS)
Symbiosis- close ecological
relationship between two or more
organisms of different species that
live in direct contact
1. MUTUALISM ( +/+)
• Both species benefit
• EX. Clown fish get shelter and
anemone gets free cleaning.
2. COMMENSALISM (+/0)
• One benefits and one is neither
helped nor harmed
EX. Barnacles get shelter on grey
whale and whale is not harmed
Eye Lash Mite
3. PARASITISM (+/-)….But not instantly killed
• Parasite: small organisms that lives
on or in the host organism
• Usually does not result in immediate
death
Example:
Tongue Louse
3. PARASITISM (+/-)….But not instantly killed
• Evolutionary adaptation keep the host
healthy enough to allow parasite
reproduction (coevolution)
EX. intestinal worms in humans
Mistletoe
Grows on
Trees
and
takes
nutrients
Cowbird Lays
egg in Robin’s
nest. Mother
raises all the
young
Mosquito
Lamprey: Steals
nutrition