Transcript Community_Ecology - Svetz-wiki

Community Ecology
Ecological Niche
• Ecological Niche – The role a certain
species plays in an ecosystem
• How does it:
o
o
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Interact with other organisms
Interact with abiotic factors
What sort of things may these include?
Example: American Alligator
Alligator: Resources
• Resources that it uses:
Opportunistic Feeders: Fish, Turtles, Smaller
Gators, Small Mammals, Birds
o So what?
o Gators eating these animals keeps populations
of dozens of other species in check
o
Alligator: Interactions
• Alligators are not aggressive unless
threatened
• Opportunistic feeders and will attack if
hungry, and within striking range
• Known to attack pets, livestock, and
humans
Alligator: Cycling of Matter
• Contribute to food chain as top predator
• Human hunting has
jeopardized alligator
populations
• Gators hunted for
meat, skin, and for
sport
• Killing alligators
effects the ecosystem
• How?
Competitive Exclusion Principle
• AKA – Gause’s Principle
• When 2 species compete for the same
resources, one is more likely to be more
successful
• The result will be in the second species
being eliminated
• Basically: 2 animals cannot occupy the
same niche
Resource Partitioning
• Some animals appear to compete for the
same resources, however when examined
closely, they occupy slightly different
niches
• Examples:
o
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Anole Lizards in the rain forest
Warblers in the same tree
Character Displacement
• AKA – Niche Shift
• Due to resource partitioning, organisms
may adapt differently to their ‘microniches’
• This would result in less competition, and
eventually divergent evolution
Realized vs. Fundamental Niche
• Fundamental Niche – The niche an
organism occupies when no competition is
present
• Realized Niche – The niche an organism
occupies when competition is present (NO
niche overlap)
Energy Flow
• All living things need energy in order to
survive
• Energy flows throughout the biosphere to
all living things
• Energy needs to be put into a living
system, otherwise it cannot function
• (DNW) What energy is constantly put into
the biosphere?
Producers
• Autotrophs – Organisms that produce
their own food
o
Because they make their own food, they
are also called producers
Producers
• Producers are the base of all ecosystems
on earth
• Producers directly and indirectly produce
all the food that goes into an ecosystem
Producers
• The most well known autotrophs used
solar energy and use Photosynthesis
• When sunlight is not present, autotrophs
use chemicals to produce food in a
process called chemosynthesis
Consumers
• Heterotrophs – Organisms that must
consume other organisms to obtain
energy
o
o
These are also known as consumers
(DNW) There are many different categories of
heterotrophs
Herbivores
• Herbivores – Organisms that obtain
energy by eating only plants
Carnivores
• Carnivores – Organisms that obtain
energy by consuming animals
Omnivores
• Omnivores – Organisms that obtain
energy by consuming both plants and
animals
Scavengers/Detritivores
• Scavengers/Detritivores – Organisms
that feed on the tissue of dead organisms
Decomposers
• Decomposers – Organisms that break
down organic matter into simple nutrients
or fertilizers
Trophic levels
• Energy moves from one organism to
another when it is eaten
• Each step in this transfer of energy Is
known as a trophic level
• Main trophic levels
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o
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Producers
Consumers
Decomposers
Energy Flow
• It is impossible to obtain all the energy in
an organism
When a rabbit eats grass, it does not obtain all
of the energy in the grass
o When a hawk eats the rabbit, it does not
obtain all the energy in the rabbit
o
• About 10% of energy is transferred from
one trophic level to the next
• This is known as the 10% law
Food Chain
• Energy flow from 1 trophic level to the
next is called a food chain
• A food chain is simplified
• Only one organism at each level are
shown
Food Chains
• Typical food chain order:
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Producers (Autotrophs)
Primary consumers (Eat autotrophs)
Secondary consumers (Eat primary consumers)
Tertiary consumers (Eat secondary consumers)
Decomposers (Break down anything dead)
Food Chain - Example
Food Web
• Animals typically eat more than just one
organism
• Food webs show a greater variety in the
diets of organisms
Arrows
• The arrows point in the direction that the
energy is transferred
• Basically, the arrows point from the prey,
to the predator
Ecological Pyramid
• Shows the relationship between
consumers and producers at different
trophic levels in an ecosystem
• Shows the relative amounts of energy at
each trophic level
• Shows what levels have the most energy
and highest # of organisms
Ecological Pyramid
Symbiosis
• Symbiosis – a close and permanent
association between different organisms
• There are three main categories of
symbiosis:
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o
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Commensalism
Mutualism
Parasitism
Commensalism
• Commensalism – When
one organism benefits,
and the other is
unaffected
Mutualism
• Mutualism – When both organisms
benefit
Parasitism
• Parasitism – When one organism
benefits, and the other is harmed
Coevolution
• Animals interacting with one another over
long periods of time have led to
coevolution
• Examples:
o
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Secondary Compounds
Camouflage
Aposematic (Warning) Coloration
Mimicry
Secondary Compounds
• Secondary Compounds – Toxic
chemicals produced in plants that are
harmful/distasteful to herbivores
• Examples:
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Nicotine
Poison Oak/Ivy
Mustard oil=Toxic to insects
Hotness of Peppers
Camouflage
• Camouflage – Any color, pattern, or
shape that enables an organism to blend
in with its surroundings
Aposomatic Coloration
• A conspicuous pattern of coloration that
warns other animals that they should not
be eaten
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o
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Poisonous
Stinging
Bad Tasting
Mimicry
• Mimicry – When two or more species
resemble one another
• 2 types:
Mullerian Mimicry – Animals with similar
defenses have similar coloration
o Batesian Mimicry – When animals with no
defenses resemble organisms that do have a
defense mechanism
o
Mullerian Batesian