Question 1

Consider two organisms, X and Y, which are involved in a type of ecological interaction. Which of the following statements is false?

Accepted Answer

A)  If X and Y are mutualists, both organisms have a positive effect on the growth of the other. 
B)  If X is a commensal organism on Y, X has a positive effect on Y, but Y has no effect on X. 
C)  If Y is a commensal organism on X, X has a positive effect on Y, but Y has no effect on X. 
D)  If X and Y are competitors, both organisms have negative effects on each other's growth. 
E)  If X is a predator and Y is prey, X has a negative effect on Y, but Y has a positive effect on X. 
A)  If X and Y are mutualists, both organisms have a positive effect on the growth of the other. 
B)  If X is a commensal organism on Y, X has a positive effect on Y, but Y has no effect on X. 
C)  If Y is a commensal organism on X, X has a positive effect on Y, but Y has no effect on X. 
D)  If X and Y are competitors, both organisms have negative effects on each other's growth. 
E)  If X is a predator and Y is prey, X has a negative effect on Y, but Y has a positive effect on X. B

Question 2

Why does the addition of extra nutrients into a lake often result in a die-off of fish and other animals?

Accepted Answer

When extra nutrirents enter a freshwater ecosystem such as lake, due to agricultural runoff, or other forms of pollution, these extra nutrients, combined with warmer temperatures, can permit explosive growth of aquatic producers such as algae and photosynthetic bacteria. These producers release oxygen into the water, which stimulates the growth of aerobic bacteria. As these aerobes increase in number and continue to deplete the oxygen in the water, the oxygen levels begin to fall, to the point where fish and other large invertebrates cannot survive. Anaerobic bacteria now increase in number, and as they release metabolic wastes, the water becomes increasing inappropriate for the survival of large animals. This series of events is known as eutrophication.

Question 3

Which of the following represents a producer in a food web?

Accepted Answer

A)  a fungus that is parasitic on plants 
B)  a herbivore 
C)  a carnivore 
D)  bacteria that break down organic material and return inorganic nutrients to the environment 
E)  photosynthetic cyanobacteria 
A)  a fungus that is parasitic on plants 
B)  a herbivore 
C)  a carnivore 
D)  bacteria that break down organic material and return inorganic nutrients to the environment 
E)  photosynthetic cyanobacteria E

Question 4

Which of the following statements about competition is true?

Accepted Answer

A)  Compared to plants or animals, competition between microorganisms is a rare event. 
B)  The principle of competitive exclusion suggests that two organisms in competition will eventually reach a stable equilibrium, where both organisms can coexist and survive. 
C)  A commensial relationship is an example of competition. 
D)  If you take an environmental sample, and find numerous microbial species within that sample, it suggests that none of these species are in competition with each other. 
E)  Compared to animals and plants, the resolution of competition between microorganisms is rapid. 
A)  Compared to plants or animals, competition between microorganisms is a rare event. 
B)  The principle of competitive exclusion suggests that two organisms in competition will eventually reach a stable equilibrium, where both organisms can coexist and survive. 
C)  A commensial relationship is an example of competition. 
D)  If you take an environmental sample, and find numerous microbial species within that sample, it suggests that none of these species are in competition with each other. 
E)  Compared to animals and plants, the resolution of competition between microorganisms is rapid.

Question 5

Which of the following statements comparing freshwater and marine environments is true?

Accepted Answer

A)  The marine environment is generally far more stable than the freshwater environment. 
B)  A seasonal thermocline may develop in a marine environment, but not a freshwater environment. 
C)  Benthic zones occur in marine environments, but not in freshwater environments. 
D)  In a marine environment, the pelagic zone usually has the highest species diversity, while in freshwater environments, diversity in the pelagic zone is usually low. 
E)  In marine environments, phosphorus is usually the principal factor limiting microbial growth. In freshwater environments, iron is usually the most principal limiting factor. 
A)  The marine environment is generally far more stable than the freshwater environment. 
B)  A seasonal thermocline may develop in a marine environment, but not a freshwater environment. 
C)  Benthic zones occur in marine environments, but not in freshwater environments. 
D)  In a marine environment, the pelagic zone usually has the highest species diversity, while in freshwater environments, diversity in the pelagic zone is usually low. 
E)  In marine environments, phosphorus is usually the principal factor limiting microbial growth. In freshwater environments, iron is usually the most principal limiting factor.

Question 6

In aquatic environments, the ________ zone represents the part of the environment where sunlight reaches the bottom.

Accepted Answer

A)  photic zone 
B)  littoral zone 
C)  profundal zone 
D)  benthic zone 
E)  pelagic zone 
A)  photic zone 
B)  littoral zone 
C)  profundal zone 
D)  benthic zone 
E)  pelagic zone

Question 7

Which process in the nitrogen cycle, carried out by certain microorganisms, converts atmospheric nitrogen into ammonia, which can then be utilized by plants?

Accepted Answer

A)  nitrogen fixation 
B)  ammonification 
C)  nitrification 
D)  denitrification 
A)  nitrogen fixation 
B)  ammonification 
C)  nitrification 
D)  denitrification

Question 8

What exactly is a biofilm? Where are biofilms found?

Accepted Answer

A biofilm is a microbial community is wh

Question 9

Which of the following statements is true?

Accepted Answer

A)  The biomass of producers in an environment will be greater than the mass of primary consumers. 
B)  The biomass of secondary consumers will be greater than that of primary consumers. 
C)  The biomass of tertiary consumers will be greater than that of quaternary consumers. 
D)  Both "a" and "c" are true. 
E)  Both "b" and "c" are true. 
A)  The biomass of producers in an environment will be greater than the mass of primary consumers. 
B)  The biomass of secondary consumers will be greater than that of primary consumers. 
C)  The biomass of tertiary consumers will be greater than that of quaternary consumers. 
D)  Both "a" and "c" are true. 
E)  Both "b" and "c" are true.

Question 10

Which of the following processes directly require the activity of microorganisms?

Accepted Answer

A)  release of organic carbon into the environment from animal and plant remains 
B)  absorption of sulfate from the environment by green plants 
C)  release of organic nitrogen into the environment by dead plants and animals 
D)  conversion of organic phosphorus in animal and plant remains into inorganic phosphorus 
E)  All of the above require microbial activity. 
A)  release of organic carbon into the environment from animal and plant remains 
B)  absorption of sulfate from the environment by green plants 
C)  release of organic nitrogen into the environment by dead plants and animals 
D)  conversion of organic phosphorus in animal and plant remains into inorganic phosphorus 
E)  All of the above require microbial activity.

Question 11

Describe why decomposers are so important in ecosystems.

Accepted Answer

Decomposers, primarily bacteria and fung

Question 12

Mycorrhizal associations would most likely be found in:

Accepted Answer

A)  benthic marine environments. 
B)  a freshwater lake. 
C)  a stream or river. 
D)  the soil environment. 
E)  microbial biofilms. 
A)  benthic marine environments. 
B)  a freshwater lake. 
C)  a stream or river. 
D)  the soil environment. 
E)  microbial biofilms.

Question 13

Most of the bacteria that live in lakes can be classified as:

Accepted Answer

A)  oligotrophs. 
B)  eutrophs. 
C)  Gram-positive. 
D)  Gram-negative. 
E)  thermophiles. 
A)  oligotrophs. 
B)  eutrophs. 
C)  Gram-positive. 
D)  Gram-negative. 
E)  thermophiles.

Consider two organisms, X and Y, which are involved in a type of ecological interaction. Which of the following statements is false?

Why does the addition of extra nutrients into a lake often result in a die-off of fish and other animals?

Which of the following represents a producer in a food web?

Which of the following statements about competition is true?

Which of the following statements comparing freshwater and marine environments is true?

In aquatic environments, the ________ zone represents the part of the environment where sunlight reaches the bottom.

Which process in the nitrogen cycle, carried out by certain microorganisms, converts atmospheric nitrogen into ammonia, which can then be utilized by plants?

What exactly is a biofilm? Where are biofilms found?

Which of the following statements is true?

Which of the following processes directly require the activity of microorganisms?

Describe why decomposers are so important in ecosystems.

Mycorrhizal associations would most likely be found in:

Most of the bacteria that live in lakes can be classified as:

Living in a Microbial World

The Chemistry of Life

The Cell: Where Life Begins

A Field Guide to the Microorganisms

The Microbiology of History and the History of Microbiology

Microbial Genetics

Metabolism and Growth

Microbial Evolution: the Origin and Diversity of Life

The Nature of Disease: a Pathogens Perspective

Host Defense

Control of Microbial Growth

Epidemiology: Who, What, When, Where, and Why

The Future Is Here: Microorganisms and Biotechnology

Guess Whos Coming to Dinner: Microorganisms and Food

Better Living With Microorganisms: Industrial and Applied Microbiology

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Exam 9: An Ecologists Guide to Microbiology

Consider two organisms, X and Y, which are involved in a type of ecological interaction. Which of the following statements is false?

Why does the addition of extra nutrients into a lake often result in a die-off of fish and other animals?

Which of the following represents a producer in a food web?

Which of the following statements about competition is true?

Which of the following statements comparing freshwater and marine environments is true?

In aquatic environments, the ________ zone represents the part of the environment where sunlight reaches the bottom.

Which process in the nitrogen cycle, carried out by certain microorganisms, converts atmospheric nitrogen into ammonia, which can then be utilized by plants?

What exactly is a biofilm? Where are biofilms found?

Which of the following statements is true?

Which of the following processes directly require the activity of microorganisms?

Describe why decomposers are so important in ecosystems.

Mycorrhizal associations would most likely be found in:

Most of the bacteria that live in lakes can be classified as:

Living in a Microbial World

The Chemistry of Life

The Cell: Where Life Begins

A Field Guide to the Microorganisms

The Microbiology of History and the History of Microbiology

Microbial Genetics

Metabolism and Growth

Microbial Evolution: the Origin and Diversity of Life

The Nature of Disease: a Pathogens Perspective

Host Defense

Control of Microbial Growth

Epidemiology: Who, What, When, Where, and Why

The Future Is Here: Microorganisms and Biotechnology

Guess Whos Coming to Dinner: Microorganisms and Food

Better Living With Microorganisms: Industrial and Applied Microbiology

Filters