Symbiosis
Objective: To understand the relationships between
species that allows them to survive.
S
Symbiosis
S Means ‘living together’; a partnership
S Explains the close relationship between two species that
allows them to ‘live together’ in order to survive
S ‘Inter-specific’: means that it occurs between different
species
Why live together?
S Due to competition for food and territory
S Animals try to avoid direct competition and form a stable
relationship (other than the predator-prey relationship)
S Sharing of space and/or food supply
Animal kingdom
S
Nile crocodile & crocodile bird
S
Hermit crab & sea anemone
S
Buffalo & oxpecker
S
Shark & remora fish
Crocodile & bird
S Nile crocodile
S Usually eats animals
S Allows bird to walk around its mouth
S Crocodile bird
S Cleans parasites in croc’s teeth
S Removes and eats scraps of food
S Eats harmful leeches and parasites
Hermit crab & sea anemone
S Hermit crab
S protects the crab
S Sea anemone
S Gets leftover food
http://www.ms-starship.com/sciencenew/symbiosis.htm
Buffalo & oxpecker
S Buffalo
S Lets the bird eat
S Oxpecker
S Eats ticks and other
parasites off skin
S Warns buffalo of
danger
http://www.pbs.org/wnet/nature/enemiespartners.html/
Shark & remora fish
S Shark
S Lets the fish eat
S Remora Fish
S Eats parasites
S Gets the shark’s leftovers
3 categories of symbiotic
interrelationships:
Mutualism
• Both species benefit from the
association.
Commensalism
• When one species benefits from the
association and the other is
unharmed.
Parasitism
• An interaction where one species
lives in/on the host; the host is often
harmed.
Mutualism
S Both species benefit
S Neither can survive without the other
S Examples
S Tickbirds and rhinos
S Flowers and bees
Commensalism
S “eating together at the same table”
S Only one member benefits
S sharing space, defense, shelter, food
S Neither will die if relationship is ended
S E.g. Pearlfish & sea cucumber
http://www.ms-starship.com/sciencenew/symbiosis.htm
Parasitism
S Not symbiotic
S Causes harm to host
S E.g. Fleas living off a dog