Question 1

Refer to the figure.
  The percentage of leaf area per tree without beetles would be _______ the percentage of leaf area per tree with beetles at 4 months.

Accepted Answer

A)  more than 
B)  less than 
C)  equal to 
D)  inverted relative to 
A)  more than 
B)  less than 
C)  equal to 
D)  inverted relative to

Question 2

Suppose the trophic efficiency between producers and herbivores is 0.1, the tropic efficiency between herbivores and carnivores is 0.15, and primary production is 1,200 units per day. What is the secondary production of herbivores?

Accepted Answer

A)  18 units per day 
B)  90 units per day 
C)  120 units per day 
D)  1,200 units per day 
A)  18 units per day 
B)  90 units per day 
C)  120 units per day 
D)  1,200 units per day

Question 3

Refer to the figure.
  The figure shows the relationship between the total autotroph biomass in the ecosystem and the ratio of heterotrophic to autotrophic biomass for lakes, coastal ocean, and open ocean. Based on the figure, at 100 mgC/m2 of autotrophic biomass, about how much of the total biomass in lake ecosystems would be expected to be in autotrophs?

Accepted Answer

A)  1% 
B)  10% 
C)  50% 
D)  90% 
A)  1% 
B)  10% 
C)  50% 
D)  90%

Question 4

Suppose the trophic efficiency between producers and herbivores is 0.1, the tropic efficiency between herbivores and carnivores is 0.15, and primary production is 1,200 units per day. What is the secondary production of carnivores?

Accepted Answer

A)  12 units per day 
B)  18 units per day 
C)  60 units per day 
D)  120 units per day 
A)  12 units per day 
B)  18 units per day 
C)  60 units per day 
D)  120 units per day

Question 5

Refer to the tables.
   Using the data in Tables 1-3, construct a food web for your study area (this will be referred to as Figure 1). Separate trophic levels with horizontal lines and number each trophic level. Indicate the classification for the species in each trophic level (i.e., secondary consumers, etc.). Indicate each species on its appropriate trophic level. Finally, sketch arrows between the species names to indicate which species consume which other species. Arrows should start at the species that was consumed and point to the species that are consumers.

Accepted Answer

The answer of Refer to the tables.
   Using...

Question 6

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

Accepted Answer

A)  assimilation; 20 
B)  assimilation; 32 
C)  consumption; 20 
D)  consumption; 32 
A)  assimilation; 20 
B)  assimilation; 32 
C)  consumption; 20 
D)  consumption; 32

Question 7

In Paine's demonstration of how removing the top predator in an intertidal food web leads to lower species diversity, the top predator was a(n)

Accepted Answer

A)  sea star. 
B)  mussel of the genus Mytilus. 
C)  acorn barnacle. 
D)  minnow. 
A)  sea star. 
B)  mussel of the genus Mytilus. 
C)  acorn barnacle. 
D)  minnow.

Question 8

Refer to the figure.
Figure 2
   Based on the food web you drew for Figure 2, which species is the most important primary producer in the system? Justify your answer. Focusing on the most important interactions, what would you predict would happen to the structure of this food web and the number of trophic levels if all individuals of species B were removed? Which species might be lost from the area as a result of the loss of species B? Which species is least likely to be affected by the loss of species B?

Accepted Answer

Species B is the most important primary

Question 9

Milkweed beetles are so named because they feed on the milkweed plant. They are _______ and are part of the _______ trophic level.

Accepted Answer

A)  herbivores; first 
B)  herbivores; second 
C)  detritivores; first 
D)  carnivores; first 
A)  herbivores; first 
B)  herbivores; second 
C)  detritivores; first 
D)  carnivores; first

Question 10

Which statement about Flecker and Townsend's studies of an aquatic trophic cascade is false?

Accepted Answer

A)  Brown trout were found to cause a greater decrease in invertebrate species density than the native galaxias did. 
B)  They demonstrated the importance of bottom-up effects. 
C)  Brown trout were found to cause a significant increase in algae compared with the effects of the native galaxias. 
D)  Artificial stream channels were used to keep fish in or out. 
A)  Brown trout were found to cause a greater decrease in invertebrate species density than the native galaxias did. 
B)  They demonstrated the importance of bottom-up effects. 
C)  Brown trout were found to cause a significant increase in algae compared with the effects of the native galaxias. 
D)  Artificial stream channels were used to keep fish in or out.

Question 11

Rank the following organisms, from highest to lowest, in terms of their expected production efficiency.

Accepted Answer

A)  Mouse > bear > grasshopper 
B)  Mouse > grasshopper > bear 
C)  Grasshopper > bear > mouse 
D)  Bear > mouse > grasshopper 
A)  Mouse > bear > grasshopper 
B)  Mouse > grasshopper > bear 
C)  Grasshopper > bear > mouse 
D)  Bear > mouse > grasshopper

Question 12

Which pyramid is most likely to be inverted?

Accepted Answer

A)  An energy pyramid in a terrestrial ecosystem 
B)  An energy pyramid in an aquatic ecosystem 
C)  A biomass pyramid in a terrestrial ecosystem 
D)  A biomass pyramid in an aquatic ecosystem 
A)  An energy pyramid in a terrestrial ecosystem 
B)  An energy pyramid in an aquatic ecosystem 
C)  A biomass pyramid in a terrestrial ecosystem 
D)  A biomass pyramid in an aquatic ecosystem

Question 13

Refer to the figure.
  Based on Flecker and Townsend's experiment, a stream with an invertebrate density of 4000/m2 would have a Chlorophyll a level closest to _______ ug/cm2 and contain _______.

Accepted Answer

A)  2.5; brown trout 
B)  1.2; no fish 
C)  0.4; no fish 
D)  1.2; Galaxias 
A)  2.5; brown trout 
B)  1.2; no fish 
C)  0.4; no fish 
D)  1.2; Galaxias

Question 14

Refer to the figure.
Figure 4
   You are studying how a contaminant moves through a food web and have collected the data shown in Figure 4. Based on the data in the figure, which biological process most likely explains the patterns observed in parts A and B of the figure?

Accepted Answer

In part A of the fig

Question 15

Which statement accurately describes the portfolio effect?

Accepted Answer

A)  Ecosystem stability creates a positive indirect effect on herbivores. 
B)  Community stability is enhanced when the population of one species cancels out variation in another such that the overall abundance in the community remains the same. 
C)  Community biodiversity does not alter the net effect of predators in a diverse population. 
D)  The greater the biomass of an ecosystem the less likely it is to be altered by disturbances. 
A)  Ecosystem stability creates a positive indirect effect on herbivores. 
B)  Community stability is enhanced when the population of one species cancels out variation in another such that the overall abundance in the community remains the same. 
C)  Community biodiversity does not alter the net effect of predators in a diverse population. 
D)  The greater the biomass of an ecosystem the less likely it is to be altered by disturbances.

Question 16

Within trophic levels, detritivores are grouped with _______ because _______.

Accepted Answer

A)  autotrophs; detritus is waste made during energy production 
B)  autotrophs; detritus is part of the first trophic level 
C)  primary carnivores; all "vores" consume animals 
D)  herbivores; detritus is part of the first trophic level 
A)  autotrophs; detritus is waste made during energy production 
B)  autotrophs; detritus is part of the first trophic level 
C)  primary carnivores; all "vores" consume animals 
D)  herbivores; detritus is part of the first trophic level

Question 17

Which statement about keystone species is true?

Accepted Answer

A)  Keystone species are always predators. 
B)  It is possible for a species to behave as a keystone species in one part of its range but not in other parts. 
C)  Keystone species have a large effect on energy flow and community composition because of their large biomass. 
D)  Keystone species are at lower trophic levels. 
A)  Keystone species are always predators. 
B)  It is possible for a species to behave as a keystone species in one part of its range but not in other parts. 
C)  Keystone species have a large effect on energy flow and community composition because of their large biomass. 
D)  Keystone species are at lower trophic levels.

Question 18

Refer to the figures.
  Which figure shows the most likely relationship between the frequency of disturbance and the number of trophic levels in the ecosystem?

Accepted Answer

A)  Figure A 
B)  Figure B 
C)  Figure C 
D)  Figure D 
A)  Figure A 
B)  Figure B 
C)  Figure C 
D)  Figure D

Question 19

In Dyer and Letourneau's studies of a trophic cascade in a lowland wet tropical forest, the Tarsobaenus beetles would best be described as

Accepted Answer

A)  herbivores. 
B)  detritivores. 
C)  secondary carnivores. 
D)  omnivores, switching between herbivory and carnivory. 
A)  herbivores. 
B)  detritivores. 
C)  secondary carnivores. 
D)  omnivores, switching between herbivory and carnivory.

Question 20

Which statement about food webs is false?

Accepted Answer

A)  A food chain (an overly simplified food web) is often too simplified to be useful in studying the impact a species has in an ecosystem. 
B)  A food web is a dynamic model describing all species interactions under all environmental conditions. 
C)  A food web can be a useful tool for understanding potential impacts invasive species have on native species when they are introduced into an ecosystem. 
D)  Food webs that try to outline every species interaction are difficult to construct and often become "spaghetti diagrams." 
A)  A food chain (an overly simplified food web) is often too simplified to be useful in studying the impact a species has in an ecosystem. 
B)  A food web is a dynamic model describing all species interactions under all environmental conditions. 
C)  A food web can be a useful tool for understanding potential impacts invasive species have on native species when they are introduced into an ecosystem. 
D)  Food webs that try to outline every species interaction are difficult to construct and often become "spaghetti diagrams."

Exam 21: Energy Flow and Food Webs

Refer to the figure. The percentage of leaf area per tree without beetles would be _______ the percentage of leaf area per tree with beetles at 4 months.

Suppose the trophic efficiency between producers and herbivores is 0.1, the tropic efficiency between herbivores and carnivores is 0.15, and primary production is 1,200 units per day. What is the secondary production of herbivores?

Suppose the trophic efficiency between producers and herbivores is 0.1, the tropic efficiency between herbivores and carnivores is 0.15, and primary production is 1,200 units per day. What is the secondary production of carnivores?

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

In Paine's demonstration of how removing the top predator in an intertidal food web leads to lower species diversity, the top predator was a(n)

Milkweed beetles are so named because they feed on the milkweed plant. They are _______ and are part of the _______ trophic level.

Which statement about Flecker and Townsend's studies of an aquatic trophic cascade is false?

Rank the following organisms, from highest to lowest, in terms of their expected production efficiency.

Which pyramid is most likely to be inverted?

Refer to the figure. Based on Flecker and Townsend's experiment, a stream with an invertebrate density of 4000/m2 would have a Chlorophyll a level closest to _______ ug/cm2 and contain _______.

Refer to the figure. Figure 4 You are studying how a contaminant moves through a food web and have collected the data shown in Figure 4. Based on the data in the figure, which biological process most likely explains the patterns observed in parts A and B of the figure?

Which statement accurately describes the portfolio effect?

Within trophic levels, detritivores are grouped with _______ because _______.

Which statement about keystone species is true?

Refer to the figures. Which figure shows the most likely relationship between the frequency of disturbance and the number of trophic levels in the ecosystem?

In Dyer and Letourneau's studies of a trophic cascade in a lowland wet tropical forest, the Tarsobaenus beetles would best be described as

Which statement about food webs is false?

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

Milkweed beetles are so named because they feed on the milkweed plant. They are _ and are part of the _ trophic level.

Refer to the figure. Based on Flecker and Townsend's experiment, a stream with an invertebrate density of 4000/m² would have a Chlorophyll a level closest to _ ug/cm² and contain _.

Within trophic levels, detritivores are grouped with _ because _.