Question 1

The movement of nutrients in ecosystems is linear.

Accepted Answer

A) True 
 B)False  False

Question 2

Why are leaf cutter ants important to the function of tropical rain forests?

Accepted Answer

Nitrogen is often a limiting nutrient in this ecosystem and leaf cutter ants contribute large amounts of fixed nitrogen to the system.

Question 3

Which of the following is not a mechanism of nutrient input to soil?

Accepted Answer

A)  mineralization 
B)  decomposition 
C)  photosynthesis 
D)  humification 
E)  none of the above 
A)  mineralization 
B)  decomposition 
C)  photosynthesis 
D)  humification 
E)  none of the above C

Question 4

What are the key similarities and differences between the nitrogen and carbon cycles?

Accepted Answer

similarities: large atmospheric pools, e

Question 5

In the carbon cycle,

Accepted Answer

A)  photosynthesis always balances respiration. 
B)  CO2 enters the ocean primarily by photosynthesis. 
C)  CO2 in the ocean forms a weak acid. 
D)  carbon enters the food chain in the form of CO3-2. 
E)  none of the above 
A)  photosynthesis always balances respiration. 
B)  CO2 enters the ocean primarily by photosynthesis. 
C)  CO2 in the ocean forms a weak acid. 
D)  carbon enters the food chain in the form of CO3-2. 
E)  none of the above

Question 6

N2 cannot be absorbed by plants.

Accepted Answer

A) True 
 B)False

Question 7

What is the effect of spatial scale on nutrient budgets?

Accepted Answer

Scale determines the potential

Question 8

Human agriculture is threatened by

Accepted Answer

A)  humus in the A horizon. 
B)  excess phosphorus and nitrogen in soil. 
C)  loss of the A horizon. 
D)  increases in mycorrhizal fungi. 
E)  none of the above 
A)  humus in the A horizon. 
B)  excess phosphorus and nitrogen in soil. 
C)  loss of the A horizon. 
D)  increases in mycorrhizal fungi. 
E)  none of the above

Question 9

The phosphorus cycle differs from the nitrogen cycle in that

Accepted Answer

A)  the phosphorus cycle has a short residence time. 
B)  there is no limiting step in the phosphorus cycle. 
C)  there is a large sedimentary pool of nitrogen. 
D)  there is a large sedimentary pool of phosphorus. 
E)  none of the above. 
A)  the phosphorus cycle has a short residence time. 
B)  there is no limiting step in the phosphorus cycle. 
C)  there is a large sedimentary pool of nitrogen. 
D)  there is a large sedimentary pool of phosphorus. 
E)  none of the above.

Question 10

When organic phosphorus is added to streams

Accepted Answer

A)  the nutrient spiral removes most of it. 
B)  it is converted into an inorganic form. 
C)  retention of phosphorus depends on the age of the surrounding forest. 
D)  retention of phosphorus requires a disturbance. 
E)  none of the above 
A)  the nutrient spiral removes most of it. 
B)  it is converted into an inorganic form. 
C)  retention of phosphorus depends on the age of the surrounding forest. 
D)  retention of phosphorus requires a disturbance. 
E)  none of the above

Question 11

The carbon cycle differs from the nitrogen cycle in that

Accepted Answer

A)  there is a large atmospheric pool of carbon. 
B)  the residence time of carbon is longer. 
C)  the nitrogen cycle requires specialized organisms. 
D)  the carbon cycle is in equilibrium. 
E)  none of the above 
A)  there is a large atmospheric pool of carbon. 
B)  the residence time of carbon is longer. 
C)  the nitrogen cycle requires specialized organisms. 
D)  the carbon cycle is in equilibrium. 
E)  none of the above

Question 12

The two main limiting processes in nutrient cycles are

Accepted Answer

A)  decomposition and nutrient spiraling. 
B)  decomposition and input of inorganic nutrients. 
C)  photosynthesis and respiration. 
D)  deposition of loess and nitrogen fixation. 
E)  none of the above 
A)  decomposition and nutrient spiraling. 
B)  decomposition and input of inorganic nutrients. 
C)  photosynthesis and respiration. 
D)  deposition of loess and nitrogen fixation. 
E)  none of the above

Question 13

During the Cambrian explosion,

Accepted Answer

A)  photosynthesis evolved. 
B)  all organisms were heterotrophs. 
C)  the atmosphere was anoxic. 
D)  many novel organisms appeared. 
E)  none of the above 
A)  photosynthesis evolved. 
B)  all organisms were heterotrophs. 
C)  the atmosphere was anoxic. 
D)  many novel organisms appeared. 
E)  none of the above

Question 14

Why is nitrogen fixation the limiting step in the nitrogen cycle?

Accepted Answer

It requires specialized organi

Question 15

Why was it important that eukaryotes use oxygen as a final electron receptor in respiration?

Accepted Answer

This allows eukaryot

Question 16

Nutrient fluxes occur by physical and biological processes.

Accepted Answer

A) True 
 B)False

Question 17

The variance in the pools and fluxes of the carbon cycle is very small.

Accepted Answer

A) True 
 B)False

Question 18

Studies of nutrient cycles at Hubbard Brook show that

Accepted Answer

A)  nitrogen is continually lost from undisturbed forest. 
B)  nutrient cycles resist disturbance. 
C)  disturbance increases stream flow and nutrient loss. 
D)  disturbance increases the rate of nitrogen cycling. 
E)  none of the above 
A)  nitrogen is continually lost from undisturbed forest. 
B)  nutrient cycles resist disturbance. 
C)  disturbance increases stream flow and nutrient loss. 
D)  disturbance increases the rate of nitrogen cycling. 
E)  none of the above

Question 19

Photosynthetic plants are not usually limited by CO2.

Accepted Answer

A) True 
 B)False

Question 20

The phosphorus cycle is driven by the fundamental processes of photosynthesis and respiration.

Accepted Answer

A) True 
 B)False

Exam 18: Biogeochemical Cycles

The movement of nutrients in ecosystems is linear.

Why are leaf cutter ants important to the function of tropical rain forests?

Which of the following is not a mechanism of nutrient input to soil?

What are the key similarities and differences between the nitrogen and carbon cycles?

In the carbon cycle,

N2 cannot be absorbed by plants.

What is the effect of spatial scale on nutrient budgets?

Human agriculture is threatened by

The phosphorus cycle differs from the nitrogen cycle in that

When organic phosphorus is added to streams

The carbon cycle differs from the nitrogen cycle in that

The two main limiting processes in nutrient cycles are

During the Cambrian explosion,

Why is nitrogen fixation the limiting step in the nitrogen cycle?

Why was it important that eukaryotes use oxygen as a final electron receptor in respiration?

Nutrient fluxes occur by physical and biological processes.

The variance in the pools and fluxes of the carbon cycle is very small.

Studies of nutrient cycles at Hubbard Brook show that

Photosynthetic plants are not usually limited by CO2.

The phosphorus cycle is driven by the fundamental processes of photosynthesis and respiration.

Introduction to Ecology

Adaptation and Evolution

Adaptations to the Physical Environment

Terrestrial Communities

Fresh-water and Marine Communities

Behavioral Ecology

The Ecology of Intraspecific Variation

Demography

Population Regulation

Life History Strategies

Competition

Coevolution I Exploitative Interactions

Mutualism

The Structure of Communities

Ecological Succession

Species Diversity

Energy Flow and Trophic Structure

Conservation Biology

Landscape Ecology

Human Global Ecology

Filters

N₂ cannot be absorbed by plants.

Photosynthetic plants are not usually limited by CO₂.