Transcript CH07_SU04

CHAPTER 7: COMMUNITY ECOLOGY
STRUCTURE
SPECIES INTERACTION
SUCCESSION
SUSTAINABILITY
Slide 1
TOPICS AND CONCEPTS
CHAPTER 7
COMMUNITIES AND STRUCTURE
ISLAND BIOGEOGRAPHY
SPECIES TYPES IN COMMUNITIES
SPECIES INTERACTIONS
PLANT SUCCESSION
STABILITY AND DISTURBANCE
Slide 2
COMMUNITY STRUCTURE
Structure can be thought of as:
Physical – for example the diameter of trees, canopy cover and layers of
vegetation or tree partitioning by various animal species such as finches.
Spatial patterns – populations dispersed randomly, clumped or uniformly.
Biodiversity
Abundance - the number of individuals of a species in an area
Richness - the number of different species in an area which is a
useful measure of the variety of ecological niches or genetic variation in a
community. It decreases as we go from the equator towards the poles
Genetic – gene frequency; number of alleles, etc.
Habitat changes – frequency of habitat changes through a fixed distance
Trophic level complexity – number of food chains (webs) in a system
Number and types of services provided by natural capital – for example
water purification
Productivity (discussed in chapter 4, pp. 79-81)
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100
COMPARISON OF PHYSICAL STRUCTURE
OF THE WORLD'S TERRESTRIAL BIOMES
30
20
50
10
ft
m
Tropical
rain forest
Coniferous
forest
Deciduous
forest
Thorn
forest
Thorn
scrub
Tall-grass
prairie
Short-grass
prairie
Desert
scrub
Figure 7-2
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Slide 4
Species by latitude animation.
Click to view
animation.
Animation
Slide 5
WHAT AFFECTS BIODIVERSITY? LATITUDE?
1,000
Species Diversity
Species Diversity
200
100
0
90ºN
100
10
60
30
0
Latitude
30ºS
60
80ºN
60
40
20
0
Latitude
Figure 7-3
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Number of diatom species
HOW DOES POLLUTION AFFECT DIVERSITY?
Unpolluted
stream
Polluted
stream
Figure 7-4
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Number of individuals per diatom species
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Species diversity
0
100
Percentage disturbance
Figure 7-13
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• THEORY OF ISLAND BIOGEOGRAPHY –
diversity of isolated area is a function of:
– Factors that influence diversity on islands are:
• Size
• Degree of isolation (distance from mainland)
• Age of island
– Species reach equilibrium where immigration rate equals
extirpation rate (not extinction!!!)
– Galapagos are a classic example of this. San Juans follow
this model. What about the Hawaiian Island chain?
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© 2004 Brooks/Cole – Thomson Learning
Rate of immigration
or extinction
High
Low
Equilibrium number
Number of species on island
Figure 7-5 (1)
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(a) Immigration and extinction rates
Slide 10
© 2004 Brooks/Cole – Thomson Learning
Rate of immigration
or extinction
High
Low
Small island
Large island
Number of species on island
Figure 7-5 (2)
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(b) Effect of island size
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© 2004 Brooks/Cole – Thomson Learning
Rate of immigration
or extinction
High
Low
Far island
Near island
Number of species on island
Figure 7-5 (3)
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(c) Effect of distance from mainland
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Area and distance effects interaction.
Click to view
animation.
Animation
Slide 13
• SPECIES TYPES IN COMMUNITIES
–
–
–
–
Keystone (flying fox)
Indicator (amphibians)
Exotic or invasive (Himalayan blackberry)
Top predator (killer whales, lions, wolves)
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Adult frog
(3 years)
Young frog
sperm
Tadpole
develops
Into frog
Sexual
reproduction
Tadpole
Eggs
Fertilized egg
development
Egg hatches
Organ formation
AMPHIBIANS ARE GOOD INDICATOR SPECIES
Figure 7-6
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• SPECIES INTERACTIONS
– Commensalism
– Mutualism
– Competition
– Predation
– Parasitism – role in macroevolution with
the development of eukaryotic cell
(predate, exploit to coexistence)
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Slide 17
Number of individuals
© 2004 Brooks/Cole – Thomson Learning
COMPETITION LEADS TO RESOURCE PARTITIONING
Species 1
Species 2
Region
of
niche overlap
Number of individuals
Resource use
Species 1
Species 2
Figure 7-7
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Resource use
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HERE THE RESOURCE
PARTITIONED IS
LOCATIONS
ON THE TREE
Figure 7-8
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DIFFERENT TYPES OF MIMICRY TO AVOID PREDATORS
Span worm
Wandering leaf insect
Poison dart frog
Viceroy butterfly mimics
monarch butterfly
Bombardier beetle
Hind wings of io moth
resemble eyes of a
much larger animal
Foul-tasting monarch
butterfly
When touched, the
snake caterpillar
changes shape to look
like the head of a snake
MIMICRY IS LOOKING OR ACTING LIKE OTHER SPECIES
TO AVOID BEING EATEN. 2 TYPES ARE
MULLERIAN AND BATESIAN
Figure 7-9
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Oxpeckers and black rhinoceros
Clown fish and sea anemone
EXAMPLES
OF
MUTUALISM
Figure 7-10
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Mycorrhizae fungi on juniper
seedlings in normal soil
Lack of mycorrhizae fungi on
juniper seedlings in sterilized soil
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COMMUNITY DYNAMICS
• PLANT SUCCESSION MODELS
– The book gives primary and secondary models (a spectrum in reality). Primary
succession is like cooking from scratch, secondary is when the structure is
changed, but the ecosystem is able to rebuild from what is left. Plant invasion of
cooling lava is a good example of primary; regeneration after fires is a good
example of secondary.
Three basic models more realistic (especially when stochastics are considered) are
– Facilitation or relay floristics (Clemens vs. Gleason)
– Inhibition
– Competition
• STABILITY
– Persistence – resistance to being disturbed or altered
– Constancy – ability to keep population numbers within limits imposed by
available resources
– Resilence – ability of community to recover after disturbance
– Restoration (back to original form and function) vs. rehabilitation (fix it up and
restore partial function.
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PRIMARY ECOLOGICAL SUCCESSION
FACILITATION (RELAY FLORISTICS) MODEL
DEVELOPED BY CLEMENS
Exposed
Lichens
rocks and mosses
Small herbs
and shrubs
Heath mat
Jack pine,
black spruce,
and aspen
Balsam fir,
paper birch, and
white spruce
climax community
Time
Figure 7-11
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SECONDARY ECOLOGICAL
SUCCESSION
Mature oak-hickory forest
Young pine forest
Annual
weeds
Perennial
weeds and
grasses
Shrubs
Time
Figure 7-12
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Slide 24
THIS IS THE END OF CHAPTER 7
THE TEST WILL COME FROM THESE LECTURE
SLIDES!!!!!!
USE THE TEXT TO CLEAR UP POINTS
OR TOPICS THAT ARE NOT CLEAR
TO YOU. THANKS FOR STUDYING
ENVIRNOMENTAL SCIENCE
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