Download Lesson 6.2

*Refer to Chapter 16 in your Textbook
Learning Goals:
1. I can describe interactions that occur in a
community.
2. I can differentiate between the types of
symbiosis.
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.