Community Ecology: Interactions in Ecosystems
Presented by
Mr. Nitin A. Ghorpade
Department of Microbiology
Deogiri College, Aurangabad
1
Topic :-
Community
ecology
Community
Ecology
C
om
m
u
n
i
t
i
es
A community
is
a
group of
organisms
of
different
species
that
live in a
particular
area
Individualistic Hypothesis
vs.
Interactive
Hypothesis
Individualistic
Hypothesis:
A
community is
a
chance group of species
found in
the same
area because they have
similar
abiotic
requirements
Interactive
Hypothesis:
A
community is
a
group of closely linked
species locked together in mandatory biotic
interactions that cause
the
community
to
function as an integrated
unit
Interspecific
Interactions
I
n
t
e
r
s
p
e
c
i
f
i
c
i
n
t
e
r
a
c
t
i
o
n
s
a
r
e
i
n
t
e
r
a
c
t
i
o
n
s
t
h
a
t
o
c
c
u
r
b
e
t
w
e
e
n
p
o
p
u
l
a
t
i
o
n
s
o
f
d
i
f
f
e
r
e
n
t
s
p
e
c
i
e
s
l
i
v
i
n
g
t
o
g
e
t
h
e
r
i
n
a
c
o
m
m
u
n
i
t
y
There
are
4 major interspecific
interactions:
Predation (and
parasitism)
Competition
Commensalism
Mutualism
Predation
(and
Parasitism)
(+
-)
The
interaction is
beneficial
to
one
species and
detrimental
to
the
other
Predation:
When
a
predator
eats
its
prey
Example
in
picture:
Predation
(and
Parasitism)
Parasitism:
Predators that
live
on
or
in their
hosts, usually
feeding off their
body
tissues or
fluids
•
Usually do not
kill
their
hosts
Examples:
Plant Defenses Against
Herbivores
“Plants
Fight
Back!”
Plants have 2
major mechanisms
by which
they
defend themselves
against being
eaten
M
e
ch
an
i
c
a
l
Defenses
•
Thorns,
hooks,
etc.
Plant Defenses Against
Herbivores
Chemical
Defenses
Produce
chemicals that
are
distasteful or
harmful
to
an
herbivore
Morphine
(opium
poppy)
Nicotine
(tobacco)
Animal
Defenses Against
Predators
Animals defend
themselves against
predators
passively
(hiding)
or actively
(fleeing)
Cryptic coloration
(camouflage)
makes prey
difficult
to
spot
Animal
Defenses Against
Predation
M
i
m
i
c
r
y
When one species
“imitates”
or “mimics”
another
Batesian
mimicry
•
When
one edible or
harmless
species
mimics
an
bad-
tasting
(unpalatable)
or harmful
species
•
Example: hawkmoth mimics
a
snake
Animal
Defenses Against
Predation
Mimicry
Mullerian
mimicry
•
Two species, both
of
which are
unpalatable (taste
bad) or
harmful,
resemble each
other
•
Example: monarch
butterfly
(unpalatable) and
queen
butterfly
(unpalatable) resemble each
other
Paras
i
t
i
sm
One
organism
(the
parasite) gets
its
nourishment from
another
organism
(the
host), which
is
harmed
in
the
process
Endoparasites:
Live within host
tissues
(tapeworms)
Ectoparasites:
Feed
on
external
surfaces
(mosquitoes)
Interspecific Competition
Competition between organisms
of
different
species
The Competitive
Exclusion
Principle:
Two
species with similar
needs
for the
same limiting
resources cannot
coexist in the
same
place
Eco
l
og
i
cal
N
i
ches
A
n
o
r
g
a
n
i
s
m
’
s
n
i
c
h
e
i
s
t
h
e
s
p
e
c
i
f
i
c
r
o
l
e
i
t
p
l
a
y
s
i
n
i
t
s
e
n
v
i
r
o
n
m
e
n
t
All of its
uses of
biotic
and abiotic
resources in
its
environment
Example:
oak
tree
in a
deciduous
forest
•
Provides oxygen to
plants, animals,
etc.
•
Home for
squirrels
•
Nesting
ground for
blue
jays
•
Takes water out of
the
soil
•
Etc.,
etc.
Commensalism
(+0)
relationship
One partner benefits,
the other
is
not
affected
Examples:
Cattle
and
cattle
egret
(birds)
Sea anemone
and
clownfish
•
Clownfish gets
a
place
to
live,
sea
anemone
is
not
affected
M
u
t
ua
l
i
sm
(++)
relationship
Both partners benefit
from the
relationship
“You scratch my back,
I’ll
scratch
yours”
Examples:
Mycorrhizae
•
Plant gets increased
water/nutrition, fungi
gets food
Hummingbirds
&
flowers
•
Hummingbirds
get
food, flowers can
reproduce
Dominant &
Keystone
Species
Dominant
Species:
Species in
a
community that have
the
highest abundance
or
highest
biomass
Sugar
maple in eastern North
America
Keystone
Species:
Important
to
a
community because of their
ecological roles (niches),
not
by
numbers
Sea otters control sea urchin
population,
which controls kelp
population
Eco
l
og
i
cal
S
u
c
c
e
ss
i
on
Ecological succession
is
a change
in the
species that live in a given area over a
period of
time
One community replaces
another
Primary
succession
=
occurs
in
places
where soil is not yet
formed
Secondary succession
= occurs
in
places
where there is soil, but where
some
disturbance has eliminated
the
previous
community
Eco
l
og
i
cal
S
u
c
c
e
ss
i
on
Eco
l
og
i
cal
S
u
c
c
e
ss
i
on
T
h
e
f
i
r
s
t
o
r
g
a
n
i
s
m
s
t
o
i
n
h
a
b
i
t
a
n
a
r
e
a
u
n
d
e
r
g
o
i
n
g
s
u
c
c
e
s
s
i
o
n
a
r
e
k
n
o
w
n
a
s
p
i
o
n
e
e
r
o
r
g
a
n
i
s
m
s
These
are
usually small organisms (bacteria,
lichens,
algae,
etc.)
The ecosystem goes through a number
of
stages,
with
each
new stage usually
consisting
of
larger
organisms than
the
last
one
O
n
c
e
a
c
o
m
m
u
n
i
t
y
h
a
s
b
e
c
o
m
e
s
t
a
b
l
e
a
n
d
i
s
n
o
t
c
h
a
n
g
i
n
g
m
u
c
h
,
i
t
i
s
k
n
o
w
n
a
s
a
c
l
i
m
a
x
c
o
m
m
u
n
i
t
y
Causes
of Ecological
Succession
There are
3
major causes
of
ecological
succession:
1.
Human
Activities
- logging, mining, development,
etc.
3.
Natural
Disasters/Disturbances
- fires, volcanic eruptions,
etc.
3.
Natural
Competition Among
Species
-
Fictitious
example:
-
turtles
and frogs
both
eat
crickets
-
frogs
are
faster,
turtles
are
slower
-
frogs eat more crickets,
turtles
starve
-
turtle
population dies out,
frog
population
gets
bigger
Community ecology, as presented by Mr. Nitin A. Ghorpade, delves into the dynamics of species interactions within ecosystems. It covers concepts like communities, individualistic vs. interactive hypotheses, interspecific interactions, predation, parasitism, plant defenses against herbivores, and more. Understanding these relationships is vital for comprehending the functioning and stability of natural ecosystems.
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Presentation Transcript
Topic :- Community ecology Presented by Mr. Nitin A. Ghorpade Department of Microbiology Deogiri College, Aurangabad 1
Communities A community is a group of organisms of different species that live in a particular area
Individualistic Hypothesis vs. Interactive Hypothesis Individualistic Hypothesis: A community is a chance group of species found in the same area because they have similar abiotic requirements Interactive Hypothesis: A community is a group of closely linked species locked together in mandatory biotic interactions that cause the community to function as an integrated unit
Interspecific Interactions Interspecific interactions are interactions that occur between populations of different species living together in a community There are 4 major interspecific interactions: Predation (and parasitism) Competition Commensalism Mutualism
Predation (and Parasitism) (+ -) The interaction is beneficial to one species and detrimental to the other Predation: When a predator eats its prey Example in picture:
Predation (and Parasitism) Parasitism: Predators that live on or in their hosts, usually feeding off their body tissues or fluids Usually do not kill their hosts Examples:
Plant Defenses Against Herbivores Plants Fight Back! Plants have 2 major mechanisms by which they defend themselves against being eaten Mechanical Defenses Thorns, hooks, etc.
Plant Defenses Against Herbivores Chemical Defenses Produce chemicals that are distasteful or harmful to an herbivore Morphine (opium poppy) Nicotine (tobacco)
Animal Defenses Against Predators Animals defend themselves against predators passively (hiding) or actively (fleeing) Cryptic coloration (camouflage) makes prey difficult to spot
Animal Defenses Against Predation Mimicry When one species imitates or mimics another Batesian mimicry When one edible or harmless species mimics an bad- tasting (unpalatable) or harmful species Example: hawkmoth mimics a snake
Animal Defenses Against Predation Mimicry Mullerian mimicry Two species, both of which are unpalatable (taste bad) or harmful, resemble each other Example: monarch butterfly (unpalatable) and queen butterfly (unpalatable) resemble each other
Parasitism One organism (the parasite) gets its nourishment from another organism (the host), which is harmed in the process Endoparasites: Live within host tissues (tapeworms) Ectoparasites: Feed on external surfaces (mosquitoes)
Interspecific Competition Competition between organisms of different species The Competitive Exclusion Principle: Two species with similar needs for the same limiting resources cannot coexist in the same place
Ecological Niches An organism s niche is the specific role it plays in its environment All of its uses of biotic and abiotic resources in its environment Example: oak tree in a deciduous forest Provides oxygen to plants, animals, etc. Home for squirrels Nesting ground for blue jays Takes water out of the soil Etc., etc.
Commensalism (+0) relationship One partner benefits, the other is not affected Examples: Cattle and cattle egret (birds) Sea anemone and clownfish Clownfish gets a place to live, sea anemone is not affected
Mutualism (++) relationship Both partners benefit from the relationship You scratch my back, I ll scratch yours Examples: Mycorrhizae Plant gets increased water/nutrition, fungi gets food Hummingbirds & flowers Hummingbirds get food, flowers can reproduce
Dominant & Keystone Species Dominant Species: Species in a community that have the highest abundance or highest biomass Sugar maple in eastern North America Keystone Species: Important to a community because of their ecological roles (niches), not by numbers Sea otters control sea urchin population, which controls kelp population
Ecological Succession Ecological succession is a change in the species that live in a given area over a period of time One community replaces another Primary succession = occurs in places where soil is not yet formed Secondary succession = occurs in places where there is soil, but where some disturbance has eliminated the previous community
Ecological Succession The first organisms to inhabit an area undergoing succession are known as pioneer organisms These are usually small organisms (bacteria, lichens, algae, etc.) The ecosystem goes through a number of stages, with each new stage usually consisting of larger organisms than the last one Once a community has become stable and is not changing much, it is known as a climax community
Causes of Ecological Succession There are 3 major causes of ecological succession: 1. Human Activities - logging, mining, development, etc. 3. Natural Disasters/Disturbances - fires, volcanic eruptions, etc. 3. Natural Competition Among Species - Fictitious example: - turtles and frogs both eat crickets - frogs are faster, turtles are slower - frogs eat more crickets, turtles starve - turtle population dies out, frog population gets bigger
