IB Environmental Systems
Review for Semester 1 Final Exam
Topics to be covered:
Systems and Models
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system defined
open, closed, isolated system
first and second laws of thermodynamics
equilibrium
positive and negative feedback
transfer vs. transformation
flow vs. storage
simple modeling
Analysing Ecosystems
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measuring physical components
measuring biotic components
 dichotomous keys
 measuring population
 measuring biomass
 measuring diversity – species richness, Simpson’s Index
measuring productivity
measuring changes
The Ecosystem
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structure
 biotic vs. abiotic
 trophic level
 pyramids – numbers, biomass, productivity
 environmental communities
 biomes - climatograms
 population interactions
function
 producers, consumers, decomposers
 photosynthesis and respiration
 energy transfer
 gross productivity, net productivity, primary productivity, secondary productivity (NPP=GPP-R)
 feedback mechanisms
change
 limiting factors and carrying capacity
 "S" and "J" population growth
 density dependent and density independent factors
 K and r strategists
 succession – primary vs. secondary, characteristics of pioneer species, pond succession vs. forest succession
 zonation
 climax communities
 pyramids
 environmental communities
 biomes
Pollution
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Point Source vs. Non Point Source Pollution
Photochemical Smog
 Sources of NOx and VOCs
 Mechanisms of formation
 Solutions
Ozone Depletion
 CFCs – composition and sources
 Chemical pathways
 Montreal Protocol
Acid Precipitation
 Sources of acid anhydrides
 Wet vs. dry deposition
 International Agreement on Transboundary Pollutants
Human Populations
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implications of exponential growth
calculation of crude birth rate, crude death rate, doubling time, natural increase rate
when given age-sex pyramid determine the stage in the demographic transition model
LEDC vs. MEDC
Demographic transition model – how to effectively move an LEDC to MEDC status
Discuss strategies for controlling human population growth
UNFPA
Review Questions
1. Think of two different ecosystems of your choice. Describe them and their location. Then do the following:
Draw an energy pyramid
List abiotic factors that affect the ecosystem
List biotic factors that affect the ecosystem
What is the biome?
List some producers, consumers, carnivores, detritivores, herbivores
Describe a positive feedback mechanism that might occur
Describe a negative feedback mechanism that might occur
What might be some limiting factors
List some K strategists and some r strategists
Characterize how the ecosystems achieve a climax community beginning with primary succession
Characterize how the ecosystems achieve a climax community beginning with secondary succession
2. The data below shows the number of individuals for the species in a community.
Species
A
B
C
D
E
a.
b.
c.
d.
e.
Number
45
2
10,000
200
2600
Which species do you think comprises the first trophic level?
Which species do you think comprises the highest trophic level?
Construct a pyramid of numbers for these data.
Explain how the 2nd Law of Thermodynamics applies to these data.
Calculate the values for Simpson’s Biodiversity
3. The data below shows the change in population of a particular organism. The total biomass is for the organism only.
Time (hr)
total biomass (g)
1
0.10
2
0.11
3
0.12
4
0.12
5
0.13
6
0.20
7
0.40
8
1.0
9
2.4
10
4.0
11
10
12
50
a. Characterize this population in terms of S vs. J growth, and K vs. r reproductive strategy. Please offer explanations.
b. Speculate on the type of organism that would represent these data.
c. Based merely on the data above, determine the productivity of this population. Would your value be GPP or NPP?
Suppose that the organism is not autotrophic (i.e. does not photo- or chemosynthesize). During the twelve hours shown above,
the organism consumed 58g of food.
d. What is the respiration rate of the organism? What is the respiratory loss for the system?
e. In the equation NP=GP-R, define each of the terms.
f. With this info, determine the GSP, NSP and R.
g. You should note that the organism consumed more food than is manifest in the standing stock of biomass after 12
days – there was about 8 grams unaccounted for. Describe what happened to these 8 grams of food.
4. Consider the flank of a volcano that is forested. An eruption occurs and a lahar wipes out one of the forested flanks. Over
the course of the next couple of hundred years the forest re-colonizes the lahar. On the back of this page, please sketch graphs
of how each of the following will change over the course of two hundred years after the lahar.
a.
b.
c.
d.
e.
f.
g.
Species Richness (how many different types of species will be present)
Bioiversity
Standing Biomass
Respiratory Loss
Productivity
Nitrogen Levels in Soil
Moisture Levels in Soil
5. A self-sustaining aquatic ecosystem was set up in a sealed, 4L container. The source of primary productivity was
due to the presence of one species of cyanobacteria. Samples were periodically pulled and concentration of the
chlorophyll was determined using a spectrograph (this is a fancy name for a machine that will measure the amount
of green coloration in a solution). From these data the relative population of the cyanobacteria could be determined.
After the first 5 hours some organisms that consume the cyanobacteria were introduced into the system. Samples
of this were also periodically pulled and the concentration was determined.
Chlorophyll
Chloroconsumer
Time (hr) Concentration
Concentration
(mg/L)
(mg/L)
0
50
0
5
60
50
10
65
45
15
78
60
30
300
100
60
1200
300
90
1190
1000
A. Graph these data.
B. What type of population growth does the cholorphyll display?
C. What type of population growth does the chloroconsumer display?
D. Predict what will happen to the population of each organism
over the next 100 years.
E. What is the net primary productivity after 5 hours?
F. What is Net Secondary Productivity during the first 15 hours?
G. What is the total net productivity of the system after 15 hours?