BI 341-Ecology
Assessment 1 Sample
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LOCATION: |
|
|
|
|
Moisture |
Medium |
Trace |
Medium |
|
pH |
5.5 |
7 |
8 |
|
N level |
Medium |
Trace |
High |
|
Soil Depth |
0.5 M |
0.1 M |
3 M |
Assessment 2 Sample:
Life History
Data (would be provided in advance):

Figure 1. Survivorship curves for a population of Adelie Penguins at Cape Crozier 1967-1969.
In Class Questions (These would not be available to you in advance):
Does banding seem to affect survivorship for Adelie Penguins? If so, when does it affect them most?
What is the probability that a banded penguin of age 2 will survive to age 16?
What are the most dangerous ages for an Adelie penguin?
Data (would be provided in advance):
Introduction:
Two barnacle species are found on the rocks in this area. Experimenters removed all individuals of species 1 in some plots. In others, they used cages to exclude barnacle predators. Each plot started with 60 barnacles of species 2.
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|
No Predators |
Control (predators present) |
|
Barnacle 1 removed |
50 |
30 |
|
Control (Barnacle 1 present) |
40 |
45 |
The experiment is repeated above the high-tide line, an area that gets more sun and less water.
The same procedure is followed, but the results are different:
|
|
No Predators |
Control (predators present) |
|
Barnacle 1 removed |
50 |
45 |
|
Control (Barnacle 1 present) |
50 |
48 |
In Class Questions (These would not be available to you in advance):
Assessment 3 - Sample
1. Productivity and Biomass
DATA (provided in advance)
A pack of 15 wolves killed approximately 200 kg of prey per day. Their main prey, moose, only produce one or two young per year (mean = 1.2). Only 80% of the females breed per year. Assume the average moose killed by wolves weighs approximately 600 kg. The territory of this pack was 25,000 ha.
Questions: (not provided in advance)
a. How many moose would it take to provide a stable food supply for a wolf pack this size?
b. How densely would the moose have to be concentrated to support this population in this territory?
c. If the moose ate several species living in this habitat (moose, elk, deer, and caribou), would their territory size increase or decrease?
2. a. Describe the likely steps necessary to produce a highly toxic plant and an herbivore that specializes in eating that plant.
b. How does that process lead to diversity in types of toxins?
3. Why do oceans have such low diversity? Why do forests have such high diversity?
4. How does removal of the top predator in a food web affect diversity?
5. If temperature alone affects productivity, and precipitation alone affects productivity, why consider them together?
Information for Final Assessment
Review these data. You will be asked to evaluate the data and speculate on their meaning, just as you have done on the past two assessments.Alewives (Alosa pseudoharengus) are small, herring-like fish that eat zooplankton. They are native to the ocean, but have been introduced to freshwater lakes, including the Great Lakes. A classic paper examined some aspects of their affect on native fauna. The researchers measured the average frequency of Daphnia (large zooplankton) and Bosmina (small zooplankton) in lakes. An additional lake (Crystal Lake) was surveyed before and 20 years after the introduction of alewives.
Frequency of individuals found in water samples:
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Species |
Lakes without alewives (average of 4 lakes) |
Lakes with alewives (average of 4 lakes) |
Crystal Lake Before alewives |
Crystal Lake 20 years after alewives introduced |
|
Daphnia spp. |
20 |
0 |
14 |
0 |
|
Bosmina spp. |
3 |
27 |
0 |
34 |
Final Assessment
REREAD the questions AFTER you have answered them. Use only the space given.
You have two study sites. One is a lake high in the Rocky Mountains. It is surrounded by rocks and the occasional pine tree. The other is a lake in a Milwaukee Park. Describe some of the major differences you would expect to find between your two sites.
a. Describe some major trends that you see.
b. Using ecological concepts, make a hypothesis to explain these patterns.
c. How could you test your hypothesis?
Why do we see this pattern?
Note: Self assessments are provided with each assessment.
Last update: 8/31/04 by Rebecca Burton, Dept. of Biology, Alverno College