Transcript Ecology of Communities - Sonoma Valley High School

Ecology of
Communities
Types of Species
Interactions
Species Interactions
• Close interaction
between species.
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Tuesday 9/5/06
Pages 397-402
Section 21-1
Predation
Parasitism
Competition
Mutualism
Commensalism
Which community is most diverse?
Why?
Predation
• Predators
capture, kill, and
consume prey.
Tuesday 9/05/06
Pages 397-402
Section 21-1
– Predators are
adapted to role.
– Prey are adapted
to survive
predator
Which species determines the number
of the other?
Predation
Tuesday 9/05/06
Pages 397-402
Section 21-1
• Mimicry
– Prey evolve
defenses
through natural
selection.
– Coloration
mimics poisonous
organism.
– Warning
coloration
Why is the western King Snake not
colored like the Arizona King Snake?
• Mimicry
– Batesian mimicry
• One poisonous, one not
– Mullerian mimicry
• Both poisonous
Predation
Tuesday 9/05/06
Pages 397-402
Section 21-1
• Plant - Herbivore
• Plants are defending
against herbivory.
– Thorns, spines, sticky
hairs.
– Secondary chemicals
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Nicotine
Strychnine
Digitalis
Poison oak
What animal group is the plant trying
to discourage?
Parasitism
Tuesday 9/05/06
Pages 397-402
Section 21-1
• Parasite is helped.
• Host is harmed.
– Ectoparsites
– Endoparasites
Why does a parasite usually not kill
its host?
Mutualism
Modern Biology
Pages 397-402
Section 21-1
• Both species benefit.
• Lichens
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2 layers of fungi
Algae cells inside.
Algae is kept moist
Fungi get food.
Are mutualism relationships species
specific?
Commensalism
• One species benefits.
• One species is not
effected.
– Lichens growing on a
tree limb.
– Cattle egrets and live
stock.
Modern Biology
Pages 397-402
Section 21-1
Competition
Modern Biology
Pages 397-402
Section 21-1
• Results from
fundamental niche
overlap.
– Competitive exclusion.
– When two species
directly compete, one
will go extinct.
What, most likely, is being competed
for in this study?
Competition
Modern Biology
Pages 397-402
Section 21-1
• Results from
fundamental niche
overlap.
– Character displacement
– Competitors evolve to
different niches.
How does the Barn Owl and Red Tail Hawk
demonstrate character displacement?
Competition
Modern Biology
Pages 397-402
Section 21-1
• Results from
fundamental niche
overlap.
– Resource partitioning.
– Each competing species
uses a portion of the
resource.
– Results in less
competition between
species.
How does the Cape may Warbler differ
from the rest of the warbler species?
Review
Pages 397-402
Section 21-1
Review
Pages 397-402
Section 21-1
How is a fundamental
niche different from a
realized niche?
Modern Biology
Pages 363-365
• Fundamental
niche
– Full range of
interactions in
ecosystem.
– All potential
resources
– Theoretical niche
as if no other
organisms present
Why is the realized niche shown above
smaller than the fundamental niche?
Key Words:
Fundamental niche
Realized niche
Ecology of
Organisms
• Modern Biology
• Pages 371-372
• Realized niche
– All resources
actually used.
– Competition with
other organisms
limits fundamental
niche.
– Something less than
the fundamental
niche.
Which species out competes the other species
regarding niche?
Properties of
Communities
• Species richness.
– The total number of
species in an
ecosystem.
Modern Biology
Pages 397-402
Section 21-1
Properties of
Communities
• Species diversity.
– The total number of
species in an
ecosystem.
– Also accounts for the
number of each
species.
Modern Biology
Pages 397-402
Section 21-1
Patterns of
Species Richness
• Closer to the equator,
the greater the
richness.
• Reasons why:
– Older communities in
tropics.
– Stable climate
– More available energy
Modern Biology
Pages 397-402
Section 21-1
Succession
• Gradual regrowth of
species after a disruption.
• Two types of succession:
– Primary (starts with pioneer
species)
– Secondary (occurs after
disruption)
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Fire
Flood
Storm
Human activity
Farming
Modern Biology
Pages 397-402
Section 21-1
Primary
Succession
• Starts slow due to lack
of minerals.
– Pioneer species first
appear.
– Eventually soil is
produced.
– Grasses appear.
– Shrubs appear.
– Finally trees appear.
Modern Biology
Pages 397-402
Section 21-1
Secondary
Succession
• Disturbance leaves just
soil intact.
• Secondary succession
starts with grasses.
• A stable climax community
results.
• Some communities never
reach stable climax
community.
Modern Biology
Pages 397-402
Section 21-1
Energy Transfers
in
Communities
Producers
• Producers use energy to
produce organic molecules.
• Autotrophs
– Use energy to produce
carbohydrates.
– Most are
photosynthetic.
– Few are
chemosynthetic.
Monday 3/23/03
Pages 415-419
Section 22-1
Measuring
Productivity
• Gross Primary
productivity:
– The rate at which
producers capture
energy.
– Equal to all of the
carbohydrates
produced using
photosynthesis.
Monday 3/23/03
Pages 415-419
Section 22-1
Measuring
Productivity
Monday 3/23/03
Pages 415-419
Section 22-1
• Net Primary Productivity.
– All organic material in an ecosystem is
referred to as biomass.
– All stored energy in the ecosystem.
– Rate at which biomass accumulates is NPP.
– GPP - carbohydrates used for living.
Consumers
• Consumers are
heterotrophs.
• Obtain energy by
consuming organic
molecules.
• Herbivores
• Carnivore
• Omnivore
• Detritivore
• Decomposers
Monday 3/23/03
Pages 415-419
Section 22-1
Energy Flow
• Energy is transferred from
organism to organism.
• Trophic level refers to
feeding position in
community
• Trophic levels:
– 1st level = producers
– 2nd level = herbivores
– 3rd level = carnivore
– 4th level = second
carnivore
Monday 3/23/03
Pages 415-419
Section 22-1
Food Chains
• A single pathway of
energy through the
ecosystem.
• Approximately 10% of
energy is preserved in
each transfer.
• 5% of sun’s energy is
preserved in the
producers.
Monday 3/23/03
Pages 415-419
Section 22-1
Food Webs
• Several food
chains
interlinked.
• Better shows
energy flow in
an ecosystem.
Monday 3/23/03
Pages 415-419
Section 22-1
Food Webs
• Several food
chains
interlinked.
• Better shows
energy flow in
an ecosystem.
Monday 3/23/03
Pages 415-419
Section 22-1
Biogeochemical
Cycle
• Energy flows
through an
ecosystem.
• Water and
minerals recycle in
the ecosystem.
– Water
– Minerals
– Carbon
Nitrogen
Calcium
Phosphorus
Wednesday 3/25/03
Pages 420-423
Section 22-2
Water Cycle
• Availability of water
determines
productivity.
– Evaporation
– Transpiration
– Precipitation
• 90% of water that
evaporates in
ecosystem passes
through plants.
Wednesday 3/25/03
Pages 420-423
Section 22-2
Carbon Cycle
• Carbon cycle is
composed of two
processes:
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– Photosynthesis
– Respiration
Autotrophs do ____.
Heterotrophs do ____.
Detritivores do ____.
Decomposers do ____.
Wednesday 3/25/03
Pages 420-423
Section 22-2
Nitrogen Cycle
• All living organisms need
nitrogen (N2)
• 78% of the atmosphere is
composed of N2.
– Only usable to a few
organisms.
– Nitrogen fixation
– Nitrogen fixation bacteria.
• Breakdown of organic
material results in ammonia.
• Nitrogen is returned to the
atmosphere.
Wednesday 3/25/03
Pages 420-423
Section 22-2
Species-Area
effect
• Larger areas support
higher degree of
richness.
• Example: islands
Modern Biology
Pages 397-402
Section 21-1
Community
Stability
• How well a community
with stands change.
• Species richness
improves stability.
• Experiment
– Grass plots
Modern Biology
Pages 397-402
Section 21-1