2. Organisms depend on each other in so many ways.
This interdependence results in different kinds of
interactions among organisms.
Interaction – a relationship between organisms that can affect their
growth, survival, and reproduction. It may be expected of organisms
that belong to the same species but is also demonstrated by
organisms of different species.
Ecologists – scientist who study the relationship of organism with
their environments, classify these relationships in terms of how they
benefit or harm the species of organisms involved in the interactions.
General classifications: competition, symbiosis, and mutualism.
3. Positive Interactions in an ecosystem
1. Mutualism
- defined as an interaction
between individuals of different
species that results in positive
(beneficial) effects on per
capita reproduction and/or
survival of the interacting
populations. – both organisms or
species benefit from each other.
- A. Dispersal – plants can’t
disperse its seeds on their own.
- Butterfly sucking the nectar
of the flower which helps in
pollination.
4. SYMBIOSIS
- two organisms of different species interact, with
at least one of the species benefiting from the
interaction while harming the other organism or
not affecting at all.
- This relationship can lead to:
- Commensalism
- Parasitism
- mutualism
5. - one organism benefits
from the interaction
without harming the
other organism.
- Involves host (organism
that provides help), and
commensal (organism
that benefits).
- Ex:
- Orchids in a tree
- Egret perch on top of
cattle or horses
6. COMPETITION
- species contends with members of
its own species for resources.
- Ex: In crowd areas, plants of the
same species compete with one
another for space, nutrients, and
materials needed for photosynthesis
such as water and sunlight. Plants
that lose out grow short and weal
and eventually die.
- Ex: animals compete to obtain food
such as chickens the faster and
sronger will be able to pick up more
grains, while the slower ones will
get lesser grains or none at all.
7. - one organism called
parasite benefits from
the interaction while
harming the other
organism called host.
- Ex:
- Aphids (tiny insects)
on the leaves of plants
- Tapeworms and
hookworms inside the
body of animal or
human
8. PREDATION
- interaction where the
predator, the bigger or
stronger organism, kills
the prey, the smaller or
weaker animal, for food.
- Ex:
- Hawk and snake
- Zebra and lion
