Download 09 Pop Fluc-Struct rubric

ICA 09 Population Dynamics/Structure
Group _____________________
Names ___________________ _______________________ ____________________
1. Population Cycles
A. What are three possible density-dependent factors affecting population cycles?
1. food availability
2. disease
3. predation
B. Develop a hypothesis with infections by a parasitic roundworm as the factor
causing cycles in grouse.
If…infections by roundworms cause populations cycles in grouse,
C. Roundworms can be treated by a drug. Develop a prediction to test your hypothesis.
then…subpopulation of grouse treated with drugs will stop cycling and have a
stable population size, while the subpopulation of grouse untreated will continue
to have cycles.
What is your independent variable? drug treatment
What is your dependent variable? cycling of population size
D. Graph your prediction. Label axes and treatments.
Put time on X axis. See graph on PPT for this lecture.
E. What is the conclusion?
Roundworm infections appear to cause the cycling of grouse.
Is the hypothesis proven? No Explain. Hypotheses are never proven; they are
supported. All possible causes of cycles have not been examined.
2. Distribution of Mimulus
Individuals from 2 species were transplanted to a range of elevations within and outside of
their native range. Individual fitness components (survival, growth, and flowers) were
measured.
A. Summarize in one concise sentence the main results for:
Lowland species: The fitness measures of the lowland species are highest in the lowest
elevation and decline with increasing elevation.
Highland species: The fitness measures of the highland species are highest in the
second highest elevation and decline with both increasing and decreasing elevation.
B. What is the main conclusion of the experiment?
Individual fitness components are highest when the individual is growing in their
native habitat.
3. Range of species
A. Summarize in one concise sentence the major pattern in:
Graph 1: Most species have very small ranges.
Graph 2: Range size increases with increasing latitude.
B. Propose a hypothesis to explain the range size at high latitudes.
1. Few species exert low competition and allow range expansion to large sizes in high
latitudes.
2. Species adapted to high latitudes encounter wide temperature fluctuations and
therefore can tolerate a broad range of temperatures spread over a large range size.
3. After glaciation, (some) species moved north again; species with high dispersal were
the ones successful in moving north and they could disperse over a large range.
4. Spatial Distribution
A. Describe in one concise sentence the owl’s spatial pattern.
The owls are concentrated in areas of old growth forest.
B. Summarize in one concise sentence the pattern for:
1. adults (top 2 graphs): Owl density and pair density increase as % old growth forest
increases.
2. offspring (bottom 2 graphs): Number of owls fledged and number offspring per pair
increase as % old growth forest increases.
C. Taking into account B, what is the explanation for the owl distribution in A?
(1 sentence) Owls are found in the highest density in the habitat in which they have
high reproductive success, viz. in old growth forest.
5. Dispersion
What type of dispersion is shown for:
A. eagle: even
Provide a hypothesis to explain its dispersion:
If…territoriality explains eagle dispersion
B. tree: clumped
Provide a hypothesis to explain its dispersion:
If…dispersal limitation explains seed dispersion around parent trees,