Transcript Conservation of Matter & Energy

Ecosystems
Introduction
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Species (be…specific!)
– Bear: not good
– American Black bear: great
– Ursus americanus: amazing
Population
Community
Ecosystem
Habitat
Niche
All ecosystems have two sets of
components.
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Biotic
– Living things
– How they interact
– Relationships
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Abiotic
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Light
Temperature
Soil
Turbidity
Wind speed
Dissolved oxygen
Slope
Salinity
Flow rate
Elevation
pH
Wave action
How do you measure biotic
components?
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Identify the species
– Use a dichotomous key
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Estimate the abundance of organisms
– Percent cover
– Percent frequency
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Estimating biomass
– The mass of living material
– It’s easiest for plants, but it’s destructive
How do you measure biotic
components?
We focused mostly on plants.
 Animals are harder to measure, why?
 There are some simple ways for smaller
organisms.
 For larger organisms, the Lincoln Index
is the easiest way.
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Lincoln Index
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Scientists capture a
sample of
individuals, mark
them, and release
them.
 Scientists then
return, capture
another sample, and
estimate the total
population
Calculating Lincoln Index
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25 birds caught,
tagged, released. 30
birds caught second
time, 18 were
marked.
Calculating Lincoln Index
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8 elephants caught,
tagged, released. 9
elephants caught
second time, 6 were
tagged.
Calculating Lincoln Index
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200 ants caught,
marked, released.
185 ants caught
second time, 57
were marked.
Calculating Lincoln Index
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20 blugill caught,
tagged, released. 30
bluegill caught
second time, 3 were
marked.
Lincoln Index Assumptions
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Population must be
closed, no immigration
or emigration
Time between samples
must be small
compared to the
lifespan
Marked organisms must
mix with the population
after marking
Lincoln Index Setbacks
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Capture can injure
animal
 Mark/tag may harm
animal
 Mark/tag may be
removed
 Mark/tag may
increase/decrease
predators
 Different individuals are
more/less “capturable”
 Individuals may become
trap-happy or trap-shy
But it’s not just about HOW
MANY living things are in an
area.
Diversity is very important as well and is
a measure of the health of an
ecosystem.
 The lower the diversity, the lower the
health.
 Why do you think this is?
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Simpson’s Diversity Index
Ecosystem 1
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15 rats
13 squirrels
8 moles
6 mice
5 chipmunks
Ecosystem 2
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0 rats
10 squirrels
3 moles
4 mice
25 chipmunks
Ecosystem 3
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16 rats
0 squirrels
7 moles
0 mice
32 chipmunks
Ecosystem 4
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3 rats
24 squirrels
2 moles
4 mice
5 chipmunks
Ecosystem 5
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10 rats
10 squirrels
7 moles
9 mice
0 chipmunks
Ecosystem 6
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85 rats
0 squirrels
0 moles
0 mice
0 chipmunks
Ecosystem 7
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3 rats
13 squirrels
0 moles
0 mice
5 chipmunks
Ecosystem 8
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0 rats
13 squirrels
0 moles
0 mice
22 chipmunks
Ecosystem 9
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15 rats
15 squirrels
15 moles
0 mice
9 chipmunks
Pyramid of Numbers
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Shows the number of
organisms at each
level.
Good for comparing
changes
Bad because numbers
can be too great to
represent and difficult
for organisms at
multiple trophic levels
Pyramid of Biomass
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Shows the amount of biomass at each level
 Difficult to measure biomass, biomass varies
over seasons
Pyramid of Productivity
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Shows the amount of energy flow through an
ecosystem (rule of 10 - each level is about 10% of
the previous level)
Good because ecosystems can be compared
Bad because the data is hard to get and species can
be at multiple trophic levels.
Gross Primary Productivity
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The amount of
energy produced or
amount of mass
produced by
producers
Net Primary Productivity
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The amount of
energy or mass that
is stored by
producers
 The amount of
energy available to
consumers
Gross Secondary Productivity
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The total amount of
energy consumed
by consumers
Net Secondary Productivity
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The total amount of
mass gained by
(primary) consumers
The data in the table below relate to the transfer of energy in a small
clearly defined habitat. The units in each case are in kJ.m-2.yr-1
Trophic Level
Gross
Production
Respiratory
Loss
Loss to
decomposers
Producers
60724
36120
477
Herbivores
21762
14700
3072
First Carnivores
714
576
42
Top Carnivores
7
4
1
Respiratory loss
by decomposers
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Calculate the Net Productivity for
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Producers
Primary Consumers (Herbivores)
Secondary Consumers (First Carnivores)
Tertiary Consumers (Top Carnivores)
3120
Calculations:
NPP of Producers:60724 - (36120+477)
NSP of Herbivores:21762
=24127 kJ.m-2.yr-1
-(14700+3072)
=3990 kJ.m-2.yr-1
NSP of Primary Consumers:714 -(576+42)
=96 kJ.m-2.yr-1
NSP of Secondary Consumers:7
=2 kJ.m-2.yr-1
-(4+1)
NSP of Decomposers:
(477+3072+42+1) -3120 =472 kJ.m-2.yr-1
ENERGY FLOW MODEL
R=36120
60724
Producers
R=576
R=14700
21762
Herbivores
714
3072
1st.
Carnivores
R=4
7
Top
Carnivores
42
477
1
Decomposers
R=3120
Trophic Level
Gross
Production
Respiratory
Loss
Loss to
decomposers
Oak Tree
61724
37120
497
Caterpillars
16700
2972
Robins
558
49
Hawks
3
1
Respiratory loss
by decomposers
3120
Trophic Level
Gross
Production
Respiratory
Loss
Loss to
decomposers
Phytoplankton
75126
41320
322
Krill
35221
17900
766
Fish
11900
4103
3247
Penguins
88
61
12
Respiratory loss
by decomposers
2792
Measuring abiotic components
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Marine Ecosystems:
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Salinity
pH
Temperature
Dissolved Oxygen
Wave Action
Measuring abiotic components
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Freshwater
ecosystems
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Turbidity
Flow Velocity
pH
Temperature
Dissolved Oxygen
Measuring abiotic components
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Terrestrial
ecosystems
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Temperature
Light intensity
Wind speed
Slope
Soil moisture
Mineral content
Measuring abiotic components
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Best method:
– Count the organisms
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Next best method:
– Capture-MarkRelease-Recapture
– (Lincoln Index)
Population Curves
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S Curve
– Reaches carrying capacity and stabilizes
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J Curve
– Unchecked population growth
Survivorship
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r- strategists
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Short generation time
Mature quickly
Small size
Many offspring
Little parental care
Adapted to unstable/
unpredictable
environments
Survivorship
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K- stragetists
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Long life/generation time
Mature slowly
Large size
Few offspring
Parental care
Predictable/stable
environments where
population stays near
carrying capacity
Population Regulation
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Density dependent
inhibition
– Population is
regulated by
negative feedback
– Crowding
– Competition
Population Regulation
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Density independent
inhibition
– Weather
– Disturbances
Succession
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A natural increase in
the complexity of the
structure and
species composition
over time
 A lifeless area
becomes an
ecosystem
Bare surface
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A lifeless abiotic
environment
becomes available
for pioneer species
 Usually r-selected
species
Seral Stage 1
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Simple soil starts
 Pioneer species
adapted to extreme
conditions colonize
Seral Stage 2
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Species diversity
increases
 Organic material
and nutrients in soil
increases
Seral Stage 3
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Larger plants
colonize
 K-selected species
become established
 r-selected species
unable to compete
get fazed out
Seral Stage 4
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Fewer new species
 Narrower niches
develop, K-selected
species become
specialists
Climax Community
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Stable and selfperpetuating
ecosystem
 Maximum
development under
temperature, light,
precipitation
conditions.
Secondary Succession
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Soils are already
established and
ready to accept
seeds blown in by
the wind
Zonation
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How an ecosystem
changes along an
environmental
gradient
 Ex:
– Mountain sides
– Sea shores
– Sea zones