Transcript Biotic Interaction

Big Idea
 The
organism’s niche determines its biotic
interaction with other organisms including
feeding relationships, competition, and
symbiosis
NICHE
the role of an organism in its ecosystem
NICHE
generalist: broad niche
•live in different habitats
•eat different things
•tolerate wide range of environment factors
specialist: narrow niches
•one type of habitat
•one type of food
•narrow range of environment factors
FUNDAMENTAL NICHE:
theoretical niche an organism
would ideally fill if other organisms
weren’t present
REALIZED NICHE:
niche that organisms actually fill
because of competitive
relationships with other organisms
No 2 species
share the
same niche
the reduction or loss
of a population due to
direct competition
with another species
N
U
M
B
E
R
TIME
N
U
M
B
E
R
TIME
N
U
M
B
E
R
TIME
Space Competition
 Sea
palm = kelp that takes
advantage of the waves
 adult kelp drops spores which
develop into young sporlings
 the young grow on the space
competitors (mussels, algae)
 young root themselves down
around competitors and pull them
off the rock with help of the waves
 leaves space for the adult
PREDATORS
•reduce the population of a prey
species
•create more available resources
•predators can create another
niche
KEYSTONE
PREDATOR
A predator that
controls the dynamic
of the entire ecosystem
Predation Can Influence the
Outcome of Competition
•prey on best competitor
•result in the persistence of a
species that would be excluded
•species determining outcome=
KEYSTONE PREDATOR
PREDATORS AND PREY
Their populations are closely linked.
•large prey population can
support more predators
•prey population grows or
shrinks, the # of predators it
can support changes as well
Classic Example: lynx and hare
Classic Example: lynx and hare
On average, how often does
the lynx population fluctuate?
On average, how often does
the hare population fluctuate?
On average, how do the peaks of predator
and prey populations compare?(do they
happen at the same time?)
SYMBIOSIS
A relationship where
2 species live closely
together.
SYMBIOSIS
3 TYPES:
•parasitism
•commensalism
•mutualism
SYMBIOSIS
PARASITISM
relationship where one
organism feeds on the tissues or
body fluids of another.
Parasitism harms one organism
and benefits the other.
SYMBIOSIS: PARASITSM
HOST
The organism on which a
parasite feeds.
SYMBIOSIS: PARASITISM: HOST
A parasite may even kill
its host.
Most do not .
SYMBIOSIS
COMMENSALISM
relationship where one
organism benefits and the other
is neither benefited nor harmed
SYMBIOSIS
MUTUALISM
relationship where both species
benefit