Learning Goals:
I can describe interactions that occur in a
community.
2. I can differentiate between the types of
symbiosis.
1.
 How
do species interact with one
another in a community?
Interactions within a Community:

Predation: occurs when one organism hunts
(predator) another organism (prey) to
consume
 Example: A leopard seal (predator) hunts and
eats an emperor penguin (prey) in Antarctica.
Interactions within a Community:

Competition: fighting over a resource such as
food, shelter, or a mate; can occur 2 ways:
1. Intraspecific: between the same species
 Ex. Hermit crabs compete for the biggest shell
2. Interspecific: between different species
 Ex. Sponges & coral compete for plankton
Interactions within a Community:

Keystone Species: a species that has vital
importance to its community; without the
keystone species, the community would be
drastically different
 Ex. Sea Otter – is a keystone species in a kelp forest. Sea otters
feed on sea urchins, which feed on kelp. Without the sea otter,
the sea urchins would over populate. If there are too many sea
urchins, there would eventually be no more kelp forest!
Interactions within a Community:
Symbiosis: “living together” occurs when 2
different species have a close relationship
within a community.
 3 types:

1. Mutualism
2. Commensalism
3. Parasitism
Types of Symbiosis:

Mutualism: occurs when both species in the
relationship benefit in some way
 Ex. Clownfish & sea anemone – fish gets a free home
& also lures food in for the anemone to eat
Types of Symbiosis:

Commensalism: occurs when 1 organism in the
relationship benefits without affecting the other
one
 Ex. The remora fish attaches himself to a shark to
gain a free ride & protection from predators.
Types of Symbiosis:

Parasitism: occurs when 1 organism in the
relationship benefits while harming the other
one
 Ex. A tapeworm lives inside a polar bears gut and
feeds off his internal organs.
Exit ticket
 Symbiosis
handout in one note.
 Complete and turn in.