Populations unit test
A test on this unit alone, marked as a percentage and a letter grade — for the test your class is actually sitting, rather than for May. Answer everything, then submit once: seeing the answer to question 3 before attempting question 4 makes the final percentage meaningless.
What doubling time is really telling you
Population pyramid shapes
Survivorship curves
Age structure diagram
Density-independent limiting factors
Density-dependent limiting factors
Biotic potential
Rule of 70
Logistic growth equation
IPAT equation
Carrying capacity
Net migration rate
Short answer 1. Define or explain: Dependency ratio
3 ptsShort answer 2. Define or explain: Population momentum
3 ptsShort answer 3. Define or explain: Female education and fertility
3 ptsShort answer 4. Define or explain: Natural decrease in Stage 5
3 ptsFree response
10 ptsThis course has no free-response prompt tagged to this unit, so one from elsewhere in the course is used. It is still worth writing — the skill transfers.
DESIGN AN INVESTIGATION. Climate change can affect both terrestrial and marine organisms. Researchers mapped the elevation zones at which five bird species (A–E) live in a tropical mountain range, and modeled where the birds would most likely live in the future under climate change predictions. BIRD SPECIES DISTRIBUTION DIAGRAM (four elevation zones; left column = current, right column = predicted future): High elevations — current: C, E future: C present, E EXTINCT Mid-high elevations — current: C future: B, C Mid-low elevations — current: B, C future: A, C, D Low elevations — current: A, B, C, D future: A only For parts F, G and H: corals cannot move in response to environmental change. Researchers conducted two experiments on the photosynthetic algae that live symbiotically in corals. • Experiment 1: algal colonies living in corals were placed in three saltwater tanks differing only in temperature — Tank 1 at 27°C (the average temperature at which most corals live), Tank 2 at 32°C, Tank 3 at 37°C — with no sediment and natural-current circulation. After 30 days researchers counted the number of bleached corals. • Experiment 2: temperature was held constant while the amount of sediment was varied — no sediment, moderate sediment, and high sediment.
A. Based on the information in the diagram, identify the elevation zone that has the highest species richness for the current distribution.
B. Describe a climate condition at high elevations that is different than it is at low elevations.
C. A predator at low elevations currently feeds on Species C and D. Based on the diagram, describe what could happen to the predator species in the future in response to the predicted changes in the prey community.
D. Species C is considered a generalist, while Species E is considered a specialist. Explain why Species C and E are predicted to respond differently to climate change.
E. Based on the diagram, explain why the bird community at low elevations in the future would be less likely to recover from natural disruptions than the current low-elevation bird community.
F. Identify the independent variable in Experiment 1.
G. Identify a likely scientific question for Experiment 1.
H. In Experiment 2 the temperature of the tanks was held constant, while the amount of sediment was varied. Explain how this modification could affect the results of this experiment.
I. One impact of climate change is the loss of ice and snow in polar regions. Describe a positive feedback loop that results from the loss of ice and snow in polar regions.
J. Describe one problem that Arctic species, such as polar bears or ringed seals, face because of warming in polar regions.