Question 1

A segment of a food web includes the following interactions:  In this example, _______ has the lowest trophic efficiency, and the _______ level supports the lowest biomass.

Accepted Answer

A)  grass F1F1F1S1F1F1F10 grasshopper; hawk 
B)  grass F1F1F1S1F1F1F10 grasshopper; grasshopper 
C)  grasshopper F1F1F1S1F1F1F10 garter snake; garter snake 
D)  garter snake F1F1F1S1F1F1F10 hawk; hawk 
E)  garter snake F1F1F1S1F1F1F10 hawk; grass

Question 2

Agricultural researchers are interested in the effect of production efficiency on economic impacts, sustainability, and production of greenhouse gases by cattle.Two groups of cattle were fed different diets.One group was fed exclusively on grass.The other was fed an energy-rich diet that included grain supplements.How would the two diets most likely affect production efficiency of the cattle?

Accepted Answer

A)  Grass-fed cattle would have a higher production efficiency. 
B)  Grain-fed cattle would have a higher production efficiency. 
C)  Production efficiencies would always be equal under the two diets. 
D)  As long as both groups ate the same amount of food, production efficiencies would be equal. 
E)  As long as grain-fed cattle ate more food than grass-fed cattle, production efficiencies would be equal.

Question 3

Which of the following would be considered an ecosystem service?

Accepted Answer

A)  The biogeochemical cycle of nitrogen 
B)  The food web of a forest 
C)  A city built on a coastline 
D)  The flood control provided by a salt marsh 
E)  Dams and levees built to control flooding

Question 4

The current cost of water treatment represents approximately 50 percent of the cost currently paid for water by residents in the city of Vancouver, Canada.Experts estimated that water treatment costs would increase by up to $0.82 per cubic meter if forest and wetland areas declined by 10 percent.This information suggests that

Accepted Answer

A)  water treatment is not an ecological service provided by forests and wetlands. 
B)  the economic value of forests and wetlands is already considered in calculating water costs. 
C)  residents of Vancouver are not willing to pay for better water treatment. 
D)  the economic value of forests and wetlands is not currently considered in calculating water costs. 
E)  residents of Vancouver are not willing to pay for maintaining forests and wetlands.

Question 5

Pacific salmon swim up freshwater rivers to breed.The watershed uphill from the rivers is forested and drains into freshwater streams where the salmon spawn and their young offspring live and grow.Managers calculated that degradation of a specific watershed from its pristine condition resulted in a loss of value of $1.6 million, yet the land was sold for $1 million to developers.This suggests that

Accepted Answer

A)  the watershed land had no obvious impact on salmon populations. 
B)  the functions of the land did not need to be taken into account when assessing its value. 
C)  the calculated value of the land accounted for the ecosystem services it provided. 
D)  the calculated value of the land did not account for the ecosystem services it provided. 
E)  the value of the land could not be accurately measured, so it could not be taken into account.

Question 6

Runoff from excess nitrogen fertilizer applied to agricultural land leads to overfertilization of water bodies, which leads to a process called _______.

Accepted Answer

The answer of Runoff from excess nitrogen fertilizer applied to...

Question 7

Pyramid diagrams show the proportion of the energy transferred from one trophic level to the next higher trophic level.This value is calculated by dividing the amount of energy at one trophic level by the amount of energy at the trophic level immediately below it.This value is called the _______.

Accepted Answer

The answer of Pyramid diagrams show the proportion of the...

Question 8

Two important marine food webs off the west coast of North America are the phytoplankton F1F1F1S1F1F1F10 zooplankton F1F1F1S1F1F1F10 fish web and the kelp F1F1F1S1F1F1F10 sea urchin F1F1F1S1F1F1F10 sea otter web.How do these two food webs compare in terms of the primary control of energy flow?

Accepted Answer

A)  Both have primarily bottom-up control; they are controlled by phytoplankton and kelp, respectively. 
B)  Both have primarily top-down control; they are controlled by fish and sea otters, respectively. 
C)  The first has primarily bottom-up control by phytoplankton; the second has primarily top-down control by sea otters. 
D)  The first has primarily top-down control by fish; the second has primarily bottom-up control by kelp. 
E)  Both food webs vary so much in resource availability that it is impossible to determine primary control.

Question 9

Grizzly bears eat a variety of both plants (grasses, roots, and berries) and animals (insects, rodents, and fish).How would the NPP of a three-level food web containing grizzly bears compare to the NPP of a three-level food web having no grizzly bears or other omnivores?

Accepted Answer

A)  There would be no effect; grizzly bears act as top carnivores. 
B)  The grizzly bear web would most likely have higher NPP. 
C)  The grizzly bear web would most likely have lower NPP. 
D)  There is no way to tell; animal diets have no effect on NPP. 
E)  There would be no effect; grizzly bears do not directly affect NPP.

Question 10

Ecosystem services are often undervalued or ignored when social and economic decisions are made.A major reason for this is that ecosystem services

Accepted Answer

A)  are not sustainable. 
B)  can be easily replaced by human technology. 
C)  have no economic value. 
D)  offer an economic value to those who benefit. 
E)  are often not noticed or understood by those who benefit.

Question 11

In a biogeochemical cycle, large amounts of an element can be stored for millions of years and remain relatively untouched.Which is the best example of such a pool?

Accepted Answer

A)  Carbon in rocks and fossil fuels 
B)  Oxygen in the atmosphere 
C)  Water in the atmosphere 
D)  Nitrogen in plant biomass 
E)  Sulfur in plant biomass

Question 12

The way energy flows through ecological communities is different from the way nutrients flow through ecological communities because

Accepted Answer

A)  there is a net gain in energy as it is transferred through trophic levels. 
B)  nutrients are altered when they are transferred among organisms. 
C)  the availability of nutrients to organisms is constant over time. 
D)  energy is ultimately lost from the system as heat. 
E)  nutrients are not influenced by how organisms acquire them.

Question 13

In a major upwelling region in the eastern equatorial Pacific Ocean, nutrient availability tends to be relatively high, compared with other parts of the ocean.Shortly after an upwelling event, nutrients including nitrogen, carbon, and phosphorus increased, and the region had a short-term phytoplankton bloom.The bloom then stopped until an iron compound was added artificially.This indicates that the region was limited by

Accepted Answer

A)  nitrogen. 
B)  phosphorus. 
C)  iron. 
D)  carbon dioxide. 
E)  sulfur.

Question 14

Compare the climates in two African ecosystems: the tropical rainforest and the Sahara.The rainforest has a very high rainfall and high biomass of trees and other vegetation.The Sahara is a desert and has extremely low rainfall and almost no vegetation.In these two ecosystems, which processes of the hydrologic cycle would be expected to predominate?

Accepted Answer

A)  Precipitation and evaporation in both ecosystems 
B)  Precipitation and transpiration in the rainforest; evaporation in the desert 
C)  Precipitation and transpiration in both ecosystems 
D)  Evaporation and transpiration in both ecosystems 
E)  Precipitation in the rainforest; evaporation and transpiration in the desert

Question 15

Organisms in an estuary, including phytoplankton, seagrasses, crustaceans, and mollusks, are all exposed to increasing acidity as atmospheric CO2 levels rise.What effect does the increased acidity likely have on these organisms?

Accepted Answer

A)  All organisms are adversely affected and some die. 
B)  All organisms are unaffected and live and reproduce normally. 
C)  Phytoplankton and seagrasses decrease photosynthesis, and crustaceans and mollusks reproduce less. 
D)  Phytoplankton and seagrasses increase photosynthesis, and crustaceans and mollusks reproduce more. 
E)  Phytoplankton and seagrasses increase photosynthesis, and crustaceans and mollusks have weaker shells.

Question 16

Which statement best explains why sustainable ecosystems are still needed in our increasingly technological society?

Accepted Answer

A)  People need ecosystems primarily for recreational purposes. 
B)  People can produce or engineer most ecosystem services artificially. 
C)  Most ecosystem services are irreplaceable or prohibitively expensive to recreate. 
D)  People still need some provisioning services (such as fresh water), but most services can be easily replaced. 
E)  Today, most ecosystem services (particularly cultural services) have already been replaced by modern technological advances.

Question 17

Which factor is least likely to have an effect on the total number of trophic levels in an ecosystem?

Accepted Answer

A)  Amount of NPP entering the ecosystem 
B)  Occasional disturbances to the ecosystem 
C)  Amount of disturbance affecting the ecosystem 
D)  Evolutionary constraints on top predators 
E)  Energy loss at each level of the ecosystem

Question 18

The experiments of David Schindler and colleagues showed that phytoplankton and cyanobacteria blooms were triggered in Canadian lakes by the addition of the nutrient _______.

Accepted Answer

The answer of The experiments of David Schindler and colleagues...

Question 19

Carbon sequestration, or removing carbon from the atmosphere and storing it in pools where it will remain long term, is frequently suggested as one possible way to remove excess greenhouse gases causing global warming.This is an example of a type of ecosystem service called a(n) _______ service.

Accepted Answer

The answer of Carbon sequestration, or removing carbon from the...

Question 20

Rising CO2 levels have many effects on Earth's ecosystems and organisms.Which effect would have the most immediate impact on Arctic organisms?

Accepted Answer

A)  Melting sea ice 
B)  Rising sea levels 
C)  Increasing ocean acidity 
D)  Shifting of bird ranges northward 
E)  Increased coastal flooding

Exam 57: Ecosystems

A segment of a food web includes the following interactions: In this example, _ has the lowest trophic efficiency, and the _ level supports the lowest biomass.