Download Notes 8.2 How Species Interact

NOTES 8.2
AN ORGANISMS NICHE
NICHE-- a unique role of a species
within an ecosystem
 Niche includes the species’ physical
home, the environmental factors
necessary for life, and interactions with
other organisms
 HABITAT-- organisms location in an
ecosystem

AN ORGANISMS NICHE

Can also be thought of as the functional
role, or job of a species in an ecosystem
WAYS IN WHICH SPECIES
INTERACT

Competition, predation, parasitism,
mutualism, and commensalism
Butterfly and Flower—Mutualistic
Symbiosis
COMPETITION
Relationship in which different
individuals or populations attempt to use
the same limited resource
 Can occur within and between species
(known as OVERLAP)

COMPETITION

Indirect competition--Species can
compete even if they never come into
direct contact with one another
(example--eat same food but at different
times of day)
COMPETITION
ADAPTATIONS TO COMPETITION
 One way competition can be reduced
between species is by dividing up the niche
in time or space
 Niche restriction-- when each species uses
less of the niche than they are capable of
using
 Example: two different barnacles use
different depths of rock to cling to

PREDATION
PREDATORS feed on PREY
 Predator-prey adaptations: camouflage,
warning coloration and mimicry

Predation
PARASITISM
One organisms (the parasite) takes
nourishment from another (the host)
 May weaken host but rarely kills it
 Examples: ticks, leeches
 When a parasite causes a disease and
sometimes death of host = PATHOGEN

Sea Lamprey is a parasitic invasive
species

Parasitized caterpillar, covered with
wasp pupae. The spines on this
large, robust caterpillar were no
protection against the parasitic
wasp that laid her eggs on or in the
caterpillar’s body. The parasitic
wasp larvae ate most of their host,
avoiding the vital organs, so that
the caterpillar stayed alive. After
they developed, the wasp larvae
spun cocoons and pupated on the
outside of the caterpillar’s body; the
white structures seen among the
spines are the cocoons of the wasp
pupae. Although the caterpillar was
still moving when this image was
taken, there was no chance that it
would itself pupate and become an
adult moth.
MUTUALISM
Close relationship between two species
in which each species provides a benefit
to the other
 Example: bacteria in digestive tract

CLOWN FISH AND SEA ANEMONE
The territorial fish protects the anemone from
anemone-eating fish, and in turn the stinging
tentacles of the anemone protects the clown
fish from its predators.
COMMENSALISM
Relationship which helps one species
and the other is not harmed
 Birds nesting in trees
 Example: tropical tree and EPIPHYTES
(smaller plants such as mosses, orchids
and ferns that live attached to bark of
tree); Anchor down but do not obtain
water or nutrients directly from tree

The hooked tips of the Burdock catch onto the hair of passing
vertebrates (cows, deer, dogs, humans) and the burs are
carried elsewhere until they finally drop off or are pulled off by
the carriers.
COMMENSALISM!
SYMBIOSIS and COEVOLUTION
Two organisms living in close
association; at least one organism
benefits
 Bees and pollination of flowers
