Question 1

In which situation are the actinomycetes likely to be most dominant?

Accepted Answer

A)  extremely acid conditions too severe for most other microorganisms 
B)  low organic matter soils 
C)  cold, wet soils 
D)  soil with lots of fresh, easily decomposed residues 
E)  neutral, moist, warm soil with lots of partially decomposed residues 
A)  extremely acid conditions too severe for most other microorganisms 
B)  low organic matter soils 
C)  cold, wet soils 
D)  soil with lots of fresh, easily decomposed residues 
E)  neutral, moist, warm soil with lots of partially decomposed residues

Question 2

Vesicles and arbuscules are structures typically formed ____.

Accepted Answer

A)  in bacterial cells when attacked by protozoa. 
B)  above ground by certain soil fungi 
C)  by mesofauna when they incorporate organic materials into the soil 
D)  in root cells by fungi when they form mycorrhizae 
E)  none of the above 
A)  in bacterial cells when attacked by protozoa. 
B)  above ground by certain soil fungi 
C)  by mesofauna when they incorporate organic materials into the soil 
D)  in root cells by fungi when they form mycorrhizae 
E)  none of the above

Question 3

Which of the following groups of organisms are responsible for greatest amount of organic matter decomposition in soils?

Accepted Answer

A)  macrofauna 
B)  microfauna 
C)  mesofauna 
D)  microflora 
E)  autotrophs 
A)  macrofauna 
B)  microfauna 
C)  mesofauna 
D)  microflora 
E)  autotrophs

Question 4

The total number of microorganisms in a hectare of soil is far greater than the number of macroorganisms, but the reverse is true for biomass of the two groups.

Accepted Answer

A) True 
 B)False

Question 5

The deeper that they are placed in the soil, the more rapidly organic compounds such as pesticides are decomposed by the soil microflora.

Accepted Answer

A) True 
 B)False

Question 6

Compared to the rest of the soil, the rhizosphere is kept relatively sterile by the action of plant roots.

Accepted Answer

A) True 
 B)False

Question 7

Of all the groups of soil organisms, bacteria have the most diverse metabolic capabilities.

Accepted Answer

A) True 
 B)False

Question 8

Mycorrhizae involve a symbiotic combination of certain bacteria and plant cells.

Accepted Answer

A) True 
 B)False

Question 9

Earthworms generally are most abundant in sandy, acid soils typically under coniferous forest vegetation.

Accepted Answer

A) True 
 B)False

Question 10

Many members of which group of soil microorganisms are anaerobic heterotrophs?

Accepted Answer

A)  actinomycetes 
B)  bacteria 
C)  fungi 
D)  both A and C 
E)  all of the above 
A)  actinomycetes 
B)  bacteria 
C)  fungi 
D)  both A and C 
E)  all of the above

Question 11

The addition of large quantities of plant residues to the soil generally ____ the incidence and severity of soil-borne plant diseases.

Accepted Answer

A)  increases 
B)  reduces 
C)  has no effect on 
A)  increases 
B)  reduces 
C)  has no effect on

Question 12

Organisms which use carbon dioxide or carbonates for their carbon source and either sunlight or inorganic chemicals for their energy source are called ____.

Accepted Answer

A)  facultative anaerobes 
B)  heterotrophs 
C)  detritivores 
D)  autotrophs 
E)  actinomycetes 
A)  facultative anaerobes 
B)  heterotrophs 
C)  detritivores 
D)  autotrophs 
E)  actinomycetes

Question 13

Mucigel is thought to improve the contact between plant roots and soil particles, thus enhancing the plant uptake of water and nutrients.

Accepted Answer

A) True 
 B)False

Question 14

A significant portion of the global production of methane comes from the activity of termites.

Accepted Answer

A) True 
 B)False

Question 15

Fungi tend to be the dominant group of microorganisms in acid, sandy soils.

Accepted Answer

A) True 
 B)False

Question 16

Most soil organisms are heterotrophs.

Accepted Answer

A) True 
 B)False

Question 17

The fungal symbiont generally benefits from the mycorrhizal relationship by obtaining ____ from the higher plant.

Accepted Answer

A)  water 
B)  phosphorus 
C)  micronutrients 
D)  A-C 
E)  none of the above 
A)  water 
B)  phosphorus 
C)  micronutrients 
D)  A-C 
E)  none of the above

Question 18

Where conditions are favorable, earthworms are known to add several hundred kg/ha of several important nutrients to the soil system.

Accepted Answer

A) True 
 B)False

Question 19

This (these) group(s) of microorganisms usually predominate(s) in sandy, acid soils.

Accepted Answer

A)  actinomycetes 
B)  bacteria 
C)  fungi 
D)  both A and C 
E)  all of the above 
A)  actinomycetes 
B)  bacteria 
C)  fungi 
D)  both A and C 
E)  all of the above

Question 20

An organism that subsists by eating predators would function as a(n) _____ in the soil ecosystem.

Accepted Answer

A)  primary consumer 
B)  detritivore 
C)  tertiary consumer 
D)  decomposer 
E)  all of the above 
A)  primary consumer 
B)  detritivore 
C)  tertiary consumer 
D)  decomposer 
E)  all of the above

In which situation are the actinomycetes likely to be most dominant?

Vesicles and arbuscules are structures typically formed ____.

Which of the following groups of organisms are responsible for greatest amount of organic matter decomposition in soils?

The total number of microorganisms in a hectare of soil is far greater than the number of macroorganisms, but the reverse is true for biomass of the two groups.

The deeper that they are placed in the soil, the more rapidly organic compounds such as pesticides are decomposed by the soil microflora.

Compared to the rest of the soil, the rhizosphere is kept relatively sterile by the action of plant roots.

Of all the groups of soil organisms, bacteria have the most diverse metabolic capabilities.

Mycorrhizae involve a symbiotic combination of certain bacteria and plant cells.

Earthworms generally are most abundant in sandy, acid soils typically under coniferous forest vegetation.

Many members of which group of soil microorganisms are anaerobic heterotrophs?

The addition of large quantities of plant residues to the soil generally ____ the incidence and severity of soil-borne plant diseases.

Organisms which use carbon dioxide or carbonates for their carbon source and either sunlight or inorganic chemicals for their energy source are called ____.

Mucigel is thought to improve the contact between plant roots and soil particles, thus enhancing the plant uptake of water and nutrients.

A significant portion of the global production of methane comes from the activity of termites.

Fungi tend to be the dominant group of microorganisms in acid, sandy soils.

Most soil organisms are heterotrophs.

The fungal symbiont generally benefits from the mycorrhizal relationship by obtaining ____ from the higher plant.

Where conditions are favorable, earthworms are known to add several hundred kg/ha of several important nutrients to the soil system.

This (these) group(s) of microorganisms usually predominate(s) in sandy, acid soils.

An organism that subsists by eating predators would function as a(n) _____ in the soil ecosystem.

The Soils Around Us

Formation of Soils From Parent Materials

Soil Classification

Soil Architecture and Physical Properties

Soil Water: Characteristics and Behavior

Soil and the Hydrologic Cycle

Soil Aeration and Temperature

The Colloidal Fraction: Seat of Soil Chemical and Physical Activity

Soil Acidity, Alkalinity, Aridity and Salinity

Soil Organic Matter Overview

Nutrient Cycles and Soil Fertility

Practical Nutrient Management

Soil Erosion and Its Control

Soils and Chemical Pollution

Filters

Exam 10: Organisms and Ecology of the Soil

In which situation are the actinomycetes likely to be most dominant?

Vesicles and arbuscules are structures typically formed ____.

Which of the following groups of organisms are responsible for greatest amount of organic matter decomposition in soils?

The total number of microorganisms in a hectare of soil is far greater than the number of macroorganisms, but the reverse is true for biomass of the two groups.

The deeper that they are placed in the soil, the more rapidly organic compounds such as pesticides are decomposed by the soil microflora.

Compared to the rest of the soil, the rhizosphere is kept relatively sterile by the action of plant roots.

Of all the groups of soil organisms, bacteria have the most diverse metabolic capabilities.

Mycorrhizae involve a symbiotic combination of certain bacteria and plant cells.

Earthworms generally are most abundant in sandy, acid soils typically under coniferous forest vegetation.

Many members of which group of soil microorganisms are anaerobic heterotrophs?

The addition of large quantities of plant residues to the soil generally ____ the incidence and severity of soil-borne plant diseases.

Organisms which use carbon dioxide or carbonates for their carbon source and either sunlight or inorganic chemicals for their energy source are called ____.

Mucigel is thought to improve the contact between plant roots and soil particles, thus enhancing the plant uptake of water and nutrients.

A significant portion of the global production of methane comes from the activity of termites.

Fungi tend to be the dominant group of microorganisms in acid, sandy soils.

Most soil organisms are heterotrophs.

The fungal symbiont generally benefits from the mycorrhizal relationship by obtaining ____ from the higher plant.

Where conditions are favorable, earthworms are known to add several hundred kg/ha of several important nutrients to the soil system.

This (these) group(s) of microorganisms usually predominate(s) in sandy, acid soils.

An organism that subsists by eating predators would function as a(n) _____ in the soil ecosystem.

The Soils Around Us

Formation of Soils From Parent Materials

Soil Classification

Soil Architecture and Physical Properties

Soil Water: Characteristics and Behavior

Soil and the Hydrologic Cycle

Soil Aeration and Temperature

The Colloidal Fraction: Seat of Soil Chemical and Physical Activity

Soil Acidity, Alkalinity, Aridity and Salinity

Soil Organic Matter Overview

Nutrient Cycles and Soil Fertility

Practical Nutrient Management

Soil Erosion and Its Control

Soils and Chemical Pollution

Filters