Transcript How Species Interact with Each Otherx

Ch8, Section 2: How Species Interact with
Each Other
Standards: SEV3e, SEV5a, b
What is a species’ niche?

 Niche- role a species has
within an ecosystem.
 Includes:
 Species physical home
 Factors needed for survival
 Interactions with other
organisms
 Ex: Bison are grazers & help
control tree sapling
populations as well as fertilize
soil for grass
 Ex: Fungi & bacteria are
decomposers, recycling
nutrients to soil.
What is a species’ habitat?

 Place where a species
lives
 An organism performs
its niche in its habitat.
How do species interact with
each other?

1.
2.
3.
4.
5.
Competition
Predation
Parasitism
Mutualism
Commensalism
1. Competition

 Relationship where individuals
or populations share limited
resources
 Both species are harmed
 -/- interaction (“lose/lose”)
 Intraspecific competitionwithin the same species.
 Ex: caterpillars of the same
species eating the same leaf.
 Interspecific competitionbetween different species
 When members of different
species compete we say their
niches have overlapped.
 Ex: hyenas compete for kill
with lions
1. Competition

 Indirect competitioncompete even though
they do not come in
contact with each other.
 Ex: An insect that eats a
leaf during the day
competes indirectly with
an insect that eats the
same leaf at night.
 Ex: Plants compete for
pollinators; humans
compete with insects for
food crop.
1. Competition

 Adaptations to
competition When 2 species compete
for a resource, usually
only one will win.
 The other species must
move to find new
resources.
 This is called competitive
exclusion.
1. Competition

 Competitive exclusion can lead
to niche restriction.
 These species share the same
niche & habitat but use a smaller
portion of it.
 Ex: Two barnacle species
Chthamalus & Balanus
 share the same intertidal zone
of a rocky shore line
 Chthamalus lives at higher tide
line (realized niche)
 When Balanus is removed,
Chthamalus will move further
down into the original Balanus
habitat. (fundamental niche)
Realized niche- where the species
actually lives
Fundamental niche- where the species
could live if given a chance.
1. Competition

Copy this down!
Realized niche- where the species
actually lives
Fundamental niche- where the species
could live if given a chance.
2. Predation

 Predator feeds on prey
 Predator benefits, prey is
harmed
 +/- interaction (win/lose)
 Some predators are very
specific about what they eat
 Canadian lynx only eat
snowshoe hares
 Creates predator/prey
oscillations
 Most predators generally eat
any prey they can capture
 Not all predators are
carnivores
2. Predation

 Animals adapted to avoid
predation:
 Camouflage- hard to see;
blend in
 Ex: some caterpillars; lizards
 Warning coloration- alert
potential predator that they
are dangerous
 Ex: poison dart frogs
 Mimicry- look like something
more dangerous even if it isn’t
 Ex: some flies have same
coloration as bees
 Protective coverings- too hard
for predator to eat.
 Ex: porcupine, turtle, cactus
3. Parasitism

 Parasite lives and feeds on host
organism.
 Parasite benefits, host is harmed
 +/- interaction (win/lose)
 Parasites are different from
predators because they do not
usually kill their host (what else
would they eat if they killed
their host?)
 Parasite can weaken host &
make them more susceptible to
disease.
 Ex: ticks, leeches, mistletoe,
fleas
4. Mutualism

 Each species benefits
from the relationship
 +/+ interaction
(win/win!)
 Some species couldn’t
live without each other
 Ex: bacteria in your
intestine; acacia tree &
ants; insects & flowers
5. Commensalism

 One species is benefited
and the other is neither
harmed nor helped.
 +/0 interaction
 Ex: orchids in trees;
clownfish & anemones;
remoras and sharks
What is Symbiosis

 Relationship where two
species live in close
association
 Often one species
benefits.
 Which of the five
species interactions are
considered symbiosis?
What is Coevolution?

 When species have such
close relationships they
often coevolve.
 These two species would
be less likely to survive if
one were missing.
 Ex: bee orchids
 This bee orchid has a
dark region with yellow
spots that resemble the
abdomen of a female
bee. Male bees will try
to copulate with the
orchid and in the process
will pollinate the
orchids.