Transcript Community Ecology Ways organisms interact ______________________ COMPETITION Between SAME and DIFFERENT kinds of organisms Compete with each other for available resources PREDATION __________________________ Between DIFFERENT kinds of.

Community Ecology
Ways organisms interact
______________________
COMPETITION
Between SAME and DIFFERENT kinds of organisms
Compete with each other for available resources
PREDATION
__________________________
Between DIFFERENT kinds of organisms
Hunt and kill other organisms to supply their energy needs
COOPERATION
__________________________
Between SAME kind of organisms
Live together and help each other
SYMBIOSIS
__________________________
Between DIFFERENT kinds of organisms
live in close association with another kind of organism
WHAT IS A RESOURCE?
Anything
needed by an organism for life
____________________________________________
Examples:
Nutrients, water, light, space
________________________
COMPETITION
Organisms in an ecosystem have to
compete with each other for available
resources. FOOD
COMPETITION
Organisms in an ecosystem have to
compete with each other for available
resources: SHELTER
COMPETITION
Organisms in an ecosystem have to
compete with each other for available
resources MATES
COMPETITION
Organisms in an ecosystem have to
compete with each other for available
resources:
Space/territory
Prairie dogs - 5 to 35 per acre
Mountain lion- 1 male per 50-300 sq. mi
COMPETITION
Organisms in an ecosystem have to
compete with each other for available
resources:
LIGHT
Ways organisms interact
___________________
PREDATION
Between DIFFERENT kinds of organisms
Hunt and kill other organisms to supply
their energy needs
PREDATION
Organisms in an ecosystem that capture
and eat other organisms to supply their
energy needs
Predator/Prey Adaptations
There are three strategies for fooling
predators;
1. To mimic a species that is distasteful
or threatening to a predator.
2. To camouflage, blending into the
background.
3. To use deceptive behavior whenever a
predator is about to attack.
Batesian Mimicry
Batesian mimicry involves a palatable, unprotected
species (the mimic) that closely resembles an unpalatable
or protected species (the model). One example is this fly
which looks like a bee. Birds know not to attack a bee as
they will be stung.
Mullerian Mimicry
Monarch
Viceroy
In Mullerian mimicry, the model is not defined and several
unpalatable species share warning colors or patterns to evade
predation. Both models and mimics are toxic. Several species
from several different orders may comprise a mimicry complex.
The advantage is that the predators need only encounter one
form to shun the entire complex.
Wasmannian Mimicry
Wasmannian Mimicry is when the mimic resembles it's host (the model)
in order to live within the same nest or structure. For example, several
jumping spiders closely resemble ants. In order to get "lost in the
crowd" and thus avoid predators.
Peckhamian (Aggressive)
Mimicry
The predator mimics its prey to capture it. The most known example
is Bird-dropping Spider. This spider hunts definite species of moths.
The spider has specific glands on the abdomen which produce
analogous of moths’ pheromones. Moth males allured by the
pheromone fly towards the spider.
Camouflage
To look, act, smell or sound such that it blend in with
their surroundings.
Leaf Mantis
Dead Leaf Butterfly
Deceptive Behavior
To display unusually pattern, which is weir to the
predator, includes color, pattern, sound, chemical
(smell), to increase their chances of escape and
survival.
Reduced Niche Size
• Due to competition and predation:
– Fundamental niche - range of conditions
that an organism can potentially tolerate
and the range of resources that it can
potentially use
– Realized niche – part of the niche that
the species actually uses due to limits
set by competition and predation
Character Displacement
• Evolution of differences in a
character due to competition ~ way
of reducing niche overlap
Resource Partitioning
• When similar species coexist, each species
may avoid competition with others by using
a specific part of an available resource
– Example: Robert MacArthur (1930-1972)
discovered that when more than one species of
warbler is foraging within the
same tree, each species hunts for
insects only in a particular section
of the tree!
INTERDEPENDENCE
All living and non-living things in an
ecosystem are interconnected and changing
even one thing impacts the whole ecosystem.
When one tugs at a single thing in nature,
he finds it attached to the rest of the world.
~John Muir, naturalist, Sierra Club founder
SHORT SUPPLY
If a nutrient is in _____________
CYCLES SLOWLY
OR __________________
it will LIMIT the growth of the
population
LIMITING FACTOR
= _____________
Kinchega National Park was droughtstricken for most of 1982 and part of
1983. Extremely low pasture biomass led
to a high mortality of kangaroos. An
estimated 14500 ± 1450 kangaroos died,
of which 9400 were western grey
kangaroos and 5100 were red kangaroos!
REMEMBER: EVERYTHING IS CONNECTED !
BIOLOGY; MIller and Levine; Prentice Hall; 2006
A decrease in the prey population means some predators will starve.
Fewer predators mean prey population will increase.
Increase in prey means more food for predators.
Predator population will increase until there is not enough food . . .
and the cycle repeats itself.
LIMITING NUTRIENT
The short
supply of a
limiting
nutrient keeps
the population
in check.
http://www.greenfacts.org/images/glossary/algae-bloom.jpg
When an ecosystem receives a LARGE input
of limiting nutrient (ie.,fertilizer runoff) the
BLOOM
population increases dramatically = ALGAL
___________
Ways organisms interact
COOPERATION
__________________
Between SAME kind of organisms
Live together and help each other
http://www.mark-ju.net/wildlife/images/monkey03.jpg
COOPERATION
Same species live together in groups
e.g. herds, packs, colonies, families, etc
Share food &
childcare
responsibilities
Groom each other
Take care of sick
COOPERATION
Same species live together in groups
EX: herds, packs, colonies, families, etc
Hunt in packs
Provide protection
Ways organisms interact
SYMBIOSIS
__________________________
Between DIFFERENT kinds of organisms
Live in close association with another kind
of organism
3 KINDS of SYMBIOSIS
______________________
MUTUALISM
Both organisms benefit
COMMENSALISM
______________________
One organism benefits;
Other is neither harmed nor helped
_____________________
PARASITISM
One organism benefits;
Other is harmed in some way
(Endoparasites/Ectoparasites)
MUTUALISM
“Good for me - Good for you”
Birds eat parasites living
on the hides of giraffes and
rhinos while enjoying
protection from predators.
Groomed animals lose their
pests.
MUTUALISM
“Good for me - Good for you”
Insects transfer pollen
between plants as they
gather nectar for food.
MUTUALISM
“Good for me - Good for you”
Clown fish gets protection from enemies
by hiding out in poisonous sea anemones
Sea anemone gets
scraps of leftover
food dropped
by fish
COMMENSALISM
“Good for me - Doesn’t bother you”
Pilot fish receive scraps of food dropped by shark;
Shark is neither harmed nor helped
COMMENSALISM
“Good for me - Doesn’t bother you”
http://www.abyssal.com/meeks/images/hermit_crab.jpg
Hermit crabs make homes in shells abandoned by snails;
Snail is not harmed by crab
Commensalism
Cattle egrets and Cape buffaloes
in Tanzania – birds feed on small
animals, such as insects and
lizards that are forced out of
their hiding places when
buffaloes roam
PARASITISM
“Good for me - Hurts you”
Barnacles are crustaceans that attach to the surface of whales
and feed on their skin and fluids; Whale is harmed
PARASITISM
“Good for me - Hurts you”
•Ehrlichiosis*
•Babesiosis
•Lyme Disease
•Rocky Mountain
Spotted Fever (RMSF)
•(Also – mosquitoes
cause heartworm!)
Tick feeds on dog’s blood;
Dog has discomfort - can get diseases/infection from bite!
PARASITISM
“Good for me - Hurts you”
Tapeworms absorb
food by living inside
host intestine;
host is harmed
Rover licks himself and
swallows flea infested with
tapeworms! Tapeworm
segments end up in Rover’s
stool in about three weeks
time!
Parasitism
• Zebra mussels grow in thick mats on each other
and other shells. Colonies can suffocate
freshwater mussel beds; they are expected to
cause the elimination of 8-10 species of native
mussels. Some rocky areas in Lake Erie are
covered with a 10-inch deep layer of zebra mussel
shells (up to 90,000 per square yard).
Patterns in communities
• Species richness: number of species in the
community – simple count of species in
community (decreases as one moves away
from the equator)
– Species-area effect: larger areas usually
contain more species than smaller areas do
• Species evenness: relative account how
abundance of each species – takes into
common each species is in the community
Disturbances
Episodes that damage biological communities, at
least temporarily, by destroying organisms and
altering the availability of resources (storms,
fires, droughts, earthquakes, floods, human
activities, clear-cutting, paving, bulldozing, etc.)
Changes that
communities go
through is called
ecological
succession
PRIMARY SUCCESSION
Community establishes self in an area that has not
supported life previously, e.g., bare rock, sand
dune, island formed by volcanic eruption
1. Autotrophic
microorganisms
move in
2. Lichens and mosses
Soil accumulates from
organic matter
3. Grasses, shrubs,
and trees move in
4. Prevalent form of
vegetation establishes
self --May take hundreds to
thousands of years
PRIMARY SUCCESSION
SECONDARY SUCCESSION
Community establishes self where an existing
community has been cleared by a disturbance, but
soil has remained in tact, e.g., agriculture
Secondary succession is usually much quicker than
primary succession for the following reasons:
•There is already an existing seed bank of
suitable plants in the soil.
•Root systems undisturbed in the soil, stumps
and other plant parts from previously existing
plants can rapidly regenerate.
•The fertility and structure of the soil has also
already been substantially modified by previous
organisms to make it more suitable for growth
and colonization.
CLIMAX COMMUNITY
• Final stage in succession
• High nutrient content in soil
• Environment can support a wide array of
life forms
• Many complex organisms can survive
• Community composition remains relatively
stable, barring further disturbances
• Organisms exist in roughly equivalent
ratios