ECOLOGICAL ECOLOGICAL
INTERACTIONSINTERACTIONS
By,By,
RAHUL M. PRATHAPRAHUL M. PRATHAP
11stst
SEM M.Sc BioinformaticsSEM M.Sc Bioinformatics

Let’s explore ....Let’s explore ....

No man is an island !!No man is an island !!
 This saying is also true for organisms in an ecosystem.
No organisms exist in isolation....
 This saying is also true for organisms in an ecosystem.
No organisms exist in isolation....

What are Ecological interactions ?What are Ecological interactions ?

Ecological interactions are the effects organisms in a
community have on one another.

Individual organisms live together in an
ecosystem and depend on one another.

In fact, they have many different types of
interactions with each other, and many of these
interactions are critical for their survival.

Ecological interactions are classified as,
1. Intraspecific interactions
2. Interspecific interactions
3. Harmonious interactions
4. Inharmonious interactions


Intraspecific interactions - Intraspecific ecological
interactions are those between individuals of the same
species.

Interspecific interactions - Interspecific ecological
interactions are ecological interactions between individuals
of different species.

Harmonious interactions - An harmonious, or positive,
ecological interaction is when none of the participating
organisms is harmed.

Inharmonious interactions - An inharmonious, or
negative, ecological interaction is when at least one of the
participating organisms is harmed.

Intraspecific interactions Interspecific interactions
Competition Protocooperation
Mutualism
Commensalism
Parasitism
Predation
Ammensalism

Types of interactions & its effects
Type of interaction Sign Effects
Mutualism +/+ Both species benefit from
interaction
Commensalism +/0 One species benefits, one
unaffected
Neutralism 0/0 Populations do not affect
one another
Ammensalism 0/- One species is unaffected,
one is disadvantaged
Predation,
Parasitism
+/- One species benefits, one
is disadvantaged
Competition -/- Each species affected
negatively

MutualismMutualism

Interspecific interaction between two organisms which
benefits both species.

Otherwise called Symbiosis

Here, this relationship is essential for the survival of at
least one member.

Mutualism types

Facultative mutualisms – Each species gains a benefit
from the presence of the other, but each can still survive
without the other.

Obligate mutualisms – Each species can only live in the
presence of the other.

Let’s see some examples....Let’s see some examples....

Mutualism
between
flowering plants
and their animal
pollinators. Plant
gets benefit from
the dispersal of
pollen, the
pollinator
obtaining a meal
of nectar
from the flower.

Mutualism between
certain ants
(Pseudomyrmex) and
a small tree, the
acacia. Acacia
provides shelter
(hollow thorns), nectar
(secreted near base of
leaves). The ants
provides several
protection like
attacking herbivorous
insects, removes
vines that might
overgrow the acacia,
and kills the growing
shoots of nearby
plants that might
become competitors.

Plover bird
cleaning the
mouth of
Crocodile.

Bacteria living in the intestines of humans and many other
animals. The human cannot digest all of the food that it heats.
The bacteria eat the food that the human cannot digest and
partially digest it, allowing the human to finish the job.

Lichens – Symbiotic association between algae & fungus. The
fungus provides a protective home for the algae to keep it moist,
and gathers mineral nutrients from rainwater and from dissolving
the rock underneath. The algae gathers energy from the sun and
prepare food that is utilized by the fungi.

Commensalism

Interspecific relationship between two organisms where
one species benefits while the other species remains
unaffected.

Barnacles have the benefit of moving through waters
attached to the whale

Titan triggerfish creates feeding opportunities for smaller fish
by moving large rocks too big for them to shift themselves

Neutralism

The most common type of interspecific interaction.

Neither population affects the other.

Examples of true neutralism are virtually impossible to
prove and most ecologists (as well as textbooks) would
agree that this concept does not exist.

Cacti and tarantulas living
in the desert

Rabbits, deer, frogs,
live together in a
grassland with no
interaction between
them.

Now it’s time to test your knowledge !!

Tell whether the relationship is Mutualism,
Commensalism or Neutralism ?
1,

Commensalism

Cattle egrets - These birds live near cattle because when
the cattle graze, their movements stir up insects. The birds
have their insects and the cattle are unaffected.

2

Mutualism

Humans and plants - It is a well known fact that plants and
humans could not exist without each other. Humans take
in oxygen from plants and gives out Carbon dioxide for
plants.

3

Neutralism

Wolves and Lion - Both hunt herbivores like deer and live
in the same forest.

4

Commensalism

Tree frog - The frog uses plants or trees for protection from
the rain.

5

Mutualism

Sea anemones and clownfish - Clownfish are often found
living amongst the tentacles of the sea anemone. While
those tentacles are able to sting nearly all other fish, the
clownfish, thanks to the mucus on its skin, is protected
from the stinging.

Clownfish have a special relationship with the anemone
and are very important to them. They are a large help to
the anemone as they clean the anemone by eating the
algae and other food leftovers on them.

THE END !!
Thank you....