UNIT 3: ECOLOGY
* Ecosystem Interactions
*
BIOTIC INTERACTIONS
(between living things)
Competition:
• Interaction between two or
more organisms competing for
the same resources in a given
habitat
Predation:
• One organism
eats another
to obtain food
Predation:
• Some animals use camouflage to avoid
predators
Predation:
• Some use bright colours to scare
predators
Predation:
• Some use mimicry (pretending to be
something else) to avoid predators
Symbiosis
• Close interaction between species
• Species either live in, or near
another species
• 3 types of Symbiosis
1) Mutualism
2) Commensalism
3) Parasitism
1) Mutualism
• both species benefit
• Ex: flowers and honey bees
an ant, a butterfly caterpillar, and an acacia plant!
caterpillars have nectar organs which the ants drink from, and the acacia tolerates the feeding caterpillars.
The ants appear to provide some protection for both plant and caterpillar
.
Red billed ox-picker and impala
Clown fish and sea anemone
anemones provide the fish with protection from predators (which cannot tolerate the stings of the anemone's tentacles) and
the fish defend the anemones against butterflyfiish which eat anemones.
2) Commensalism
• one species benefits from another
without affecting the other species
• Ex: Egret forages in fields among cattle and horses.
Feeds on insects stirred up by the grazing animals.
The egret benefits from this relationship, while the
livestock are typically unaffected by it.
3) Parasitism
• one species benefits at expense of
another
• parasites live IN or ON host species
• Ex: ticks and deer
SUMMARY
Type of
Species
relationship
harmed
Commensalism
Parasitism
Mutualism
= 1 species
Species
benefits
Species
neutral