The Living World: Biodiversity 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.
Island biogeography
Founder effect
Umbrella and flagship species
Why the diversity measure changes the answer
Seed banks
Habitat fragmentation
Genetic bottleneck
Indicator species
Ecological succession
Ecosystem resilience vs resistance
Species-area curve
Adaptations to disturbance
Short answer 1. Define or explain: Shannon-Wiener index
3 ptsShort answer 2. Define or explain: Levels of biodiversity
3 ptsShort answer 3. Define or explain: Keystone species
3 ptsShort answer 4. Define or explain: Zone of physiological stress
3 ptsFree response
10 ptsDESIGN AN INVESTIGATION. A state park contains several ponds that have been colonized by an invasive aquatic plant. Park biologists have observed that ponds with dense mats of the invasive plant appear to contain fewer native submerged plant species than ponds without it. They want to determine whether the invasive plant is reducing native plant diversity, and if so, whether the mechanism is competition for light. The biologists have access to twelve ponds of similar size, depth and water chemistry — six with dense invasive mats and six without — as well as quadrat sampling frames, a light meter that measures irradiance underwater, and floating shade cloth of adjustable density.
A(i). Identify a testable hypothesis about the mechanism the biologists suspect. A(ii). Identify the independent variable in a controlled experiment designed to test that mechanism. A(iii). Identify the dependent variable.
B(i). Describe how the biologists could use the shade cloth to test the light-competition mechanism without introducing the invasive plant into uninvaded ponds. B(ii). Describe an appropriate control for that experiment.
C. Explain why the comparison of the six invaded ponds with the six uninvaded ponds, by itself, cannot establish that the invasive plant causes the loss of native species.
D. Describe how the biologists should use the quadrat frames to obtain an unbiased estimate of native plant cover in a pond.
E. Identify one characteristic that commonly makes a species successful as an invader, and explain why it confers an advantage.
F. Describe one method the park could use to control the invasive plant, and identify one drawback of that method.