AP Biology: Chapter 55: Ecosystems
Margaret Bahe
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
1.  This profile was measured in San Pablo Bay on February
6, 1996. The sunlight was being absorbed rapidly by
suspended particles and was completely absent at about
2.5 meters depth. This condition is typical of northern San
Francisco Bay, with high concentrations of suspended
solids. Only the shallow upper layers of the water column
have sufficient sunlight for photosynthesis.
2.  2. This light profile was measured in Central Bay on
February 6, 1996. In this case sunlight was present down
to 5 meters. Usually the Central Bay has relatively clear
water, with maximum light penetration reaching 8 meters.
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
View from above Lake 226 divider curtain in August 1973.
The bright green colour results from bluegreen algae
(Cyanobacteria), which are growing on phosphorus
added to the near site.
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
#61 Practice Problem from the practice exam. DISCUSS
(A)
This option is incorrect because the phosphate is limiting;
thus, additional nutrients would have no effect.
(B)
This option is incorrect because the addition of nitrogen, an
essential plant nutrient, would not decrease the algal growth.
(C)
This option is correct because the limiting nutrient is
phosphate, not nitrogen. (TEACHER SDISAGREE WHICH
IS THE CORRECT ANSWER!!)
(D)
This option is incorrect because adding nitrogen, an essential
plant nutrient, would not increase then decrease the algal
growth.
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
The correct answer could be any value from 1.4–1.7 months.
Note: The data are reflective of actual data. To calculate the
lag time in months between the change in the densities of the
prey and the predator populations, calculate the differences
between the prey and predator peaks or valleys. The first
peak of oscillation is the prey at 4.8 months; the predator hits
the first peak at approximately 6.5 months. The first valley of
oscillation is the prey at 8.5 with the second at 10. When
calculating the difference between lag time, subtract 8.5 from
10 to obtain 1.5 months.
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
The correct answer is 340–360. The graph depicts a logistic
growth curve for a population. The formula to calculate the
per capita rate increase between days 3 and 5 is !N/!T,
where !N=change in population size and !T=time interval. In
other words, !N/!T = 900 individuals-200 individuals/2
days=700 individuals/2 days. However, the mean rate of
population growth is for 1 day, or 350 individuals/day.
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
Do the sequence on the board
For what processes do plants and then animals use this
energy that they trap?
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
Pick several organisms and identify their trophic level
What level is the human?
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
Where does primary productivity fit into this picture?
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
The correct answer is 26 or 25. The problem is an application of the
first law of thermodynamics, not the “10 percent rule” of energy
transformation. To work this problem, all numbers should be
converted to the same KJ/m2. There are TWO possible ways to
arrive at the correct answer.
First, 14,100 KJ/m2 is 74.3 percent of the total accumulated biomass,
so the shrubs would possess 25.7 percent of the total biomass.
A more complex pathway to the same answer is as follows: Energy
accumulated as biomass is 1.9 x 104 KJ/m2 or 19,000 KJ/m2 and is
distributed among the tree layer, shrub layer, and herb layer. The
energy accumulated as biomass in the tree layer is 1.3 x 104 KJ/ m2 or
13,000 KJ/m2, and the energy accumulated as biomass in the herb
layer is 1.1 x 103 KJ/m2 or 1,100 KJ/m2. Together, the energy
accumulated as biomass in the tree and herb layers is 13,000 + 1,100
KJ/m2. Subtracting this amount from the total of 19,000 KJ/ m2
leaves 4,900 KJ/m2 energy accumulated as biomass (“tied up”) in the
shrub layer. This percentage of the total can be calculated as 4,900
KJ/m2 /19,000 KJ/m2 = .257 or 25.7 percent.
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
The correct answer is 60. The herbivores receive 125 g/m2
from the grass. 60 g/m2 is lost to decomposers, and 5 g/m2
is lost to predators. 125 – 60 – 5 = 60 g/m2 left for the
herbivores to use in metabolic activity.
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
#12 (A)
This option is incorrect. The quantitative data provided in the
scenario do not support this conclusion regarding changes in
biomass for coyotes and hawks.
(B)
This option is correct. It demonstrates an understanding
of the components of a food web and interactions
between all of the participants. Coyotes prey on deer and
rabbits, and if developers remove them, coyotes will lose
their primary source of nutrition/energy. With this loss of
nutrition/energy they will experience a decrease in
reproductive success and therefore a significant decline
in their population.
(C)
This option is incorrect. The data do not provide evidence to
support the conclusion that with the removal of deer and
rabbits the coyotes will switch to preying on voles and
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
Examples of Biomagnification: (Consequence of the food
chain, persistence in the envrionment, lipid solubility, novel
compound with no enzyme sto break it down)
DDT, Mercury, PCBs
PCBs are persistent organic pollutants and have entered the
environment through both use and disposal. The
environmental transport of PCBs is complex and nearly
global in scale. The public, legal, and scientific concerns
about PCBs arose from research indicating they were likely
carcinogens having the potential to adversely impact the
environment and therefore undesirable as commercial
products. Despite active research spanning five decades,
extensive regulatory actions, and an effective ban on their
production since the 1970s, PCBs still persist in the
environment and remain a focus of attention"
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
Farmers and Fertilizers
Legumes and Root Nodules
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
Farmers and Fertilizers
Legumes and Root Nodules
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
Results from the Hubbard Brook Experiment
6 different valleys; monitored runnoff from watershed; 60% of
water left through creeks (40% evapotranspirated)
Collected rain water and measured mineral content in it
Bed rock really close to surface, so water must runoff through
the creek
Constructed dam and weir to collect water; measure nutrient
content
Found: Interanl cycling in intact forest conserves nutrient
content
Experiment: clear cut one forest; spray with herbicide prevent
plant regrowth; measure runoff
Water runoff 30-40% increase
Mineral losses were huge: Calcium up 4 times, K+ up by 15
times, nitrate up 60 times!
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
Results from the Hubbard Brook Experiment
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
See Additional ppt and handout
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
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Chapter 55: Ecosystems
AP Biology:AP Biology:Margaret
Bahe
Chapter 52: Biome
Pictures
Margaret Bahe
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Chapter 55: Ecosystems
AP Biology:AP Biology:Margaret
Bahe
Chapter 52: Biome
Pictures
Margaret Bahe
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Chapter 55: Ecosystems
AP Biology:AP Biology:Margaret
Bahe
Chapter 52: Biome
Pictures
Margaret Bahe
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Chapter 55: Ecosystems
AP Biology:AP Biology:Margaret
Bahe
Chapter 52: Biome
Pictures
Margaret Bahe
http://www.californiachaparral.com/boldgrowthchaparral.html
Marriage of an old-growth legacy manzanita (Arctostaphylos
glauca) and an Engelmann oak that has lasted for more than
a century. No fire needed here!
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Chapter 55: Ecosystems
AP Biology:AP Biology:Margaret
Bahe
Chapter 52: Biome
Pictures
Margaret Bahe
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Chapter 55: Ecosystems
AP Biology:AP Biology:Margaret
Bahe
Chapter 52: Biome
Pictures
Margaret Bahe
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Chapter 55: Ecosystems
AP Biology:AP Biology:Margaret
Bahe
Chapter 52: Biome
Pictures
Margaret Bahe
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
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AP Biology: Chapter 55: Ecosystems
Margaret Bahe
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