Exam IV Ecology

According to the figure, at 1,000 mgC/m 2 of autotrophic biomass, lakes would be predicted to have a(n) _______ biomass pyramid, coastal oceans to have a(n) _______ biomass pyramid, and open oceans to have a(n) _______ biomass pyramid.

A. regular; regular; regular

B. regular; regular; inverted

C. inverted; inverted; regular

D. inverted; regular; regular

B

Based on the figure, at 100 mgC/m 2 of autotrophic biomass, about how much of the total biomass in lake ecosystems would be expected to be in autotrophs?

A. 90%

B. 1%

C. 50%

D. 10%

C

Milkweed beetles are so named because they feed on the milkweed plant. They are an example of a(n) _______ and are part of the _______ trophic level.

A. detritivore; first

B. herbivore; first

C. herbivore; second

D. carnivore; first

C

Which trophic level generates the most dead organic material in most ecosystems?

A. Fourth

B. First

C. Third

D. Second

B

The diagram below is an example of an inverted _______ pyramid, which is most likely to be found in a(n) _______ ecosystem.

A. biomass; terrestrial

B. biomass; aquatic

C. energy; terrestrial

D. energy; aquatic

B

If herbivores eat 320 kg of plants, and the total plant biomass is 1,600 kg, the _______ efficiency is ________%.

A. assimilation; 32

B. consumption; 32

C. consumption; 20

D. assimilation; 20

C

All other things being equal, herbivores generally must consume _______ food than carnivores in order to meet their nutritional needs. The reason is that plant material, per gram of carbon, contains _______ nitrogen than animal material does.

A. more; less

B. less; less

C. more; more

D. less; more

A

The availability of nutrient cations such as Ca 2+, K +, and Mg 2+ to plants may be insufficient in some soils that have low amounts of _______ particles. These particles have _______ that allow them to hold onto cations and exchange them with the soil solution.

A. clay; weak negative charges

B. clay; irregular structures

C. sand; strong positive charges

D. sand; semicrystalline structures

A

Which of the following is one example of the ways in which Arctic plant communities have avoided competition through resource partitioning?

A. Arctic species lack chemicals that inhibit growth of other species.

B. Different Arctic plant species grow at different rates.

C. All Arctic species are able to use both inorganic and organic nitrogen.

D. Different Arctic plant species take up nitrogen at different depths of the soil.

D

When leaves change color during senescence,

A. chlorophyll is broken down and the plant resorbs up to 60‒70% of the nitrogen of the leaves.

B. chlorophyll is broken down and the plant resorbs 5‒10% of the nitrogen of the leaves.

C. carbohydrates and starches are broken down and moved into stems and roots.

D. Both a and c

D

The largest pool of carbon can be found in

A. sediments and rocks.

B. land surface, including soils and vegetation.

C. the atmosphere.

D. oceans.

A

Before the Industrial Revolution, the flux of carbon from the terrestrial to the atmospheric pools _______ the flux in the opposite direction. Today, the flux of carbon from the terrestrial to atmospheric pools _______ the flux in the opposite direction.

A. was about equal to; exceeds

B. was about equal to; is less than

C. exceeded; is about equal to

D. exceeded; exceeds

A

Which statement about the nitrogen cycle is false?

A. Despite their relatively small size, the land and ocean surface pools of nitrogen have very high biological activity.

B. Human activities have greatly altered the global nitrogen cycle.

C. Atmospheric nitrogen exists primarily in the unreactive dinitrogen gas form.

D. The nitrogen cycle is not linked to the carbon cycle.

D

Increasing levels of carbon dioxide in the oceans make them _______ acidic. This change affects the ability of marine organisms to form protective shells made up of _______ carbonate.

A. more; phosphorus

B. less; calcium

C. more; magnesium

D. more; calcium

D

Which of the following would most likely encounter the greatest difficulty in responding to climate change?

A. A long-lived tree

B. A butterfly

C. A rodent

D. A biennial shrub with animal-dispersed seeds

A

In eutrophic waters, algal growth is _______, leading to _______ decomposition rates and thus _______ levels of oxygen.

A. increased; lower; lower

B. increased; higher; higher

C. increased; higher; lower

D. decreased; higher; higher

C

The figure below shows the pH of precipitation in the United States in 1994 (top) and 2004 (bottom). The acidity of precipitation during both time periods was most extreme in the _______ part of the country, and the acidity of precipitation in this area _______ between 1994 and 2004.

A. western; increased

B. eastern; decreased

C. western; did not change

D. eastern; increased

B

As nitrogen input increases, _______ remains nearly constant at first and then increases rapidly at higher levels of nitrogen input.

A. nitrogen mineralization

B. leaf nitrogen concentration

C. NO3- leaching and soil acidification

D. net primary productivity

C

Between 1880 and 2012, the average annual global surface temperature

A. increased 2.0°C.

B. increased 0.8°C.

C. increased 0.2°C.

D. decreased 0.8°C.

B

A reduction in aerosols in the atmosphere would tend to _______ temperatures, because aerosols _______ sunlight.

A. increase; reflect

B. increase; absorb

C. decrease; reflect

D. None of the above; a change in aerosol concentrations should not result in detectable climate change.

A

The activity of an earthworm species increases the fertility of soils in an agricultural field. This is an example of

A. an ecosystem service.

B. a surrogate service.

C. restoration management.

D. ecosystem management.

A

The introduction of invasive plant species all over the world and the resulting extinction of native, endemic species has led to

A. anthropogenic Allee effects.

B. taxonomic diversity.

C. genetic homogenization.

D. taxonomic homogenization.

D

If half of the pollinators were removed at random, about _______% of the plants would still be visited by pollinators.

A. 15

B. 65

C. 50

D. 85

D

Which of the following is an example of taxonomic homogenization?

A. Hybridization of California tiger salamanders with another species

B. Addition of invasive generalist species to native communities

C. Decrease in distribution of non-native species in crater lakes in Africa

D. Replacement of endemic snails on Pacific islands by invasive species

D

A highway severely inhibits movements of Florida cooters (a species of turtle) between sections of their habitat. For the cooters, this situation is one of habitat

A. homogenization.

B. fragmentation.

C. loss.

D. degradation.

B

Two genetic consequences of small population size that affect the survival of species are _______ and _______.

A. hybridization; loss of genetic variability

B. inbreeding; increase in genetic variability

C. inbreeding; loss of genetic variability

D. hybridization; increase in genetic variability

C

The Eurasian zebra mussels that are found in North America are an example of

A. a species that has been brought back from the brink of extinction by ex situ conservation.

B. an invasive species that is preying upon native species.

C. an invasive species that is outcompeting native species.

D. a species that has become threatened due to habitat fragmentation.

C

A landscape is an area that must be

A. sampled via aerial photography.

B. at least 1 ha in area.

C. spatially heterogeneous with respect to at least one element or feature.

D. shaped as a quadrilateral.

C

Which statement about edge effects is true?

A. They always inhibit dispersal.

B. They can consist of biotic changes associated with a boundary.

C. They are never barriers to dispersal.

D. Abiotic conditions usually do not change at the boundary.

B

In the figure below, what is the correct ranking (from best to worst) of these three arrangements of core natural areas in terms of their value as conservation sites?

A. C is better than A, which is better than B.

B. A is better than B, which is better than C.

C. A is better than C, which is better than B.

D. B is better than A, which is better than C.

C