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Ecological Interactions
Interactions Between Species
Ecological Interaction
Ecological (or Biological) Interactions
are the effects organisms in a
community have on one another. In
nature, no organism exists entirely in
isolation, and therefore every
organism must interact with the
environment and other organisms.
An organism's interactions with its
environment and other species are
essential to the survival of the
organism and the functioning of the
the ecosystem. They can affect
distribution and abundance of
organism, and can influence
evolution.
Key Definitions
Population: A population is a
group of individuals OF THE
SAME SPECIES living in the
same area, potentially
interacting.
Community: A community is a
group of populations OF
DIFFERENT SPECIES living in the
same area, potentially
interacting.
Neutralism
Effect of X: 0 Effect on Y: 0
Neutralism describes the
relationship between two species
that interact but do not affect
each other. It describes
interactions where the health of
one species has absolutely no
effect whatsoever on that of the
other. There are no examples of
this in nature, because the
complexity of ecosystems makes
it impossible to assert which
factors affect which organisms.
Amensalism
Effect of X: 0 Effect on Y: Amensalism describes the
relationship between two species
that interact where one species
has a negative impact on the
other without benefitting itself. A
clear case of amensalism is
where sheep or cattle trample
grass. Whilst the presence of the
grass causes negligible
detrimental effects to the animals
hoof, the grass suffers from being
crushed.
Commensalism
Effect of X: + Effect on Y: 0
Commensalism describes the
relationship between two species
that interact where one species
benefits from the interaction while
the other is unaffected. A good
example of commensalism is a
remora living with a shark. Remoras
eat leftover food from the shark, and
therefore benefits. The shark is not
affected in the process, as the
remoras only eat leftover food, and
therefore do not deplete the shark’s
resources.
Competition
Effect of X: - Effect on Y: Competition describes the
relationship between two species
that interact where both species or
organisms are negatively impacted by
the interaction. This occurs in
occasions such as when two species
share the same food source, and
therefore are competing for the best
food supply. Because both must eat
from the same source, both species
will have less food than if the
interaction did not take place.
Antagonism
Effect of X: + Effect on Y: Antagonism describes the
relationship between two species
that interact where one species
benefits from the interaction
while the other is negatively
impacted. A basic example is
carnivorism, since the predator
benefits from the interaction by
eating, and the prey dies, which
is obviously a detrimental effect
on the species.
Mutualism
Effect of X: + Effect on Y: +
Mutualism describes the relationship
between two species that interact
where both species benefit from the
interaction. Within a species this is
called co-operation. A well-known
example of mutualism is the
relationship between ungulates
ungulates (such cows) and bacteria
within their intestines. The ungulates
benefit from the cellulase produced
by the bacteria, which aids in
digestion. The bacteria benefit from
having a stable supple of nutrient in
the host environment.
Strange Interactions
Thanks For Watching!
By Jane Harding