LSU ENVS 1126 FINAL EXAM QUESTIONS WITH 100%
CORRECT ANSWERS AND DETAILED RATIONALE:
Table of Contents
Section Domain Approx. Questions Page Reference
1 Ecology Fundamentals 30 Page 1
2 Population Dynamics 30 Page 2
3 Nutrient Cycling 25 Page 3
4 Biodiversity 25 Page 4
5 Energy Resources 30 Page 5
6 Pollution 30 Page 6
7 Environmental Policy 30 Page 7
Section 1: Ecology Fundamentals
1. What is the primary source of energy for almost all ecosystems on
Earth?
A) Geothermal heat
B) The sun
C) Wind
D) Decomposers
Correct Answer: B. Rationale: The sun provides the energy that drives
photosynthesis, forming the base of most food webs.
,2. Which of the following is an abiotic factor in an ecosystem?
A) Bacteria
B) Fungi
C) Temperature
D) Plants
Correct Answer: C. Rationale: Abiotic factors are non-living chemical
and physical parts of the environment.
3. What is the process by which plants convert light energy into
chemical energy?
A) Cellular respiration
B) Photosynthesis
C) Transpiration
D) Decomposition
Correct Answer: B. Rationale: Photosynthesis converts solar energy into
glucose, which is used by the plant and other organisms.
4. Which trophic level contains the greatest amount of energy in a
food web?
A) Primary consumers
B) Secondary consumers
C) Producers
D) Tertiary consumers
Correct Answer: C. Rationale: Producers (autotrophs) capture the initial
solar energy, and energy decreases at each subsequent trophic level
due to the 10% rule.
5. What term describes the maximum population size an environment
can sustain indefinitely?
A) Biotic potential
,B) Carrying capacity
C) Limiting factor
D) Ecological footprint
Correct Answer: B. Rationale: Carrying capacity is the maximum
number of individuals of a species that an environment can support.
6. Which organism is considered a keystone species in a kelp forest
ecosystem?
A) Sea urchin
B) Sea otter
C) Kelp
D) Sunflower star
Correct Answer: B. Rationale: Sea otters prey on sea urchins, preventing
the urchins from overgrazing and destroying the kelp forest.
7. What is the primary difference between a food chain and a food
web?
A) A food chain is larger
B) A food web is more interconnected
C) A food chain only includes plants
D) A food web only includes animals
Correct Answer: B. Rationale: A food web consists of multiple
interconnected food chains, showing a more realistic flow of energy.
8. Which biome is characterized by permafrost and low-growing
vegetation?
A) Taiga
B) Tundra
C) Temperate deciduous forest
D) Grassland
, Correct Answer: B. Rationale: The tundra biome has a permanently
frozen subsoil layer known as permafrost, which limits plant growth.
9. What is the role of a decomposer in an ecosystem?
A) Produces energy from sunlight
B) Breaks down dead organic matter
C) Consumes primary producers
D) Regulates predator populations
Correct Answer: B. Rationale: Decomposers, like bacteria and fungi,
break down dead organisms and waste, returning nutrients to the soil.
10. Which of the following represents an organism's fundamental
niche?
A) The actual conditions it occupies
B) The full range of conditions it could theoretically occupy
C) Its role as a predator
D) Its physical habitat only
Correct Answer: B. Rationale: The fundamental niche is the entire set of
conditions under which an organism can survive and reproduce, while
the realized niche is the actual conditions it occupies due to
competition.
11. What type of succession occurs after a disturbance that leaves the
soil intact?
A) Primary succession
B) Secondary succession
C) Tertiary succession
D) Climax succession
Correct Answer: B. Rationale: Secondary succession occurs when a
CORRECT ANSWERS AND DETAILED RATIONALE:
Table of Contents
Section Domain Approx. Questions Page Reference
1 Ecology Fundamentals 30 Page 1
2 Population Dynamics 30 Page 2
3 Nutrient Cycling 25 Page 3
4 Biodiversity 25 Page 4
5 Energy Resources 30 Page 5
6 Pollution 30 Page 6
7 Environmental Policy 30 Page 7
Section 1: Ecology Fundamentals
1. What is the primary source of energy for almost all ecosystems on
Earth?
A) Geothermal heat
B) The sun
C) Wind
D) Decomposers
Correct Answer: B. Rationale: The sun provides the energy that drives
photosynthesis, forming the base of most food webs.
,2. Which of the following is an abiotic factor in an ecosystem?
A) Bacteria
B) Fungi
C) Temperature
D) Plants
Correct Answer: C. Rationale: Abiotic factors are non-living chemical
and physical parts of the environment.
3. What is the process by which plants convert light energy into
chemical energy?
A) Cellular respiration
B) Photosynthesis
C) Transpiration
D) Decomposition
Correct Answer: B. Rationale: Photosynthesis converts solar energy into
glucose, which is used by the plant and other organisms.
4. Which trophic level contains the greatest amount of energy in a
food web?
A) Primary consumers
B) Secondary consumers
C) Producers
D) Tertiary consumers
Correct Answer: C. Rationale: Producers (autotrophs) capture the initial
solar energy, and energy decreases at each subsequent trophic level
due to the 10% rule.
5. What term describes the maximum population size an environment
can sustain indefinitely?
A) Biotic potential
,B) Carrying capacity
C) Limiting factor
D) Ecological footprint
Correct Answer: B. Rationale: Carrying capacity is the maximum
number of individuals of a species that an environment can support.
6. Which organism is considered a keystone species in a kelp forest
ecosystem?
A) Sea urchin
B) Sea otter
C) Kelp
D) Sunflower star
Correct Answer: B. Rationale: Sea otters prey on sea urchins, preventing
the urchins from overgrazing and destroying the kelp forest.
7. What is the primary difference between a food chain and a food
web?
A) A food chain is larger
B) A food web is more interconnected
C) A food chain only includes plants
D) A food web only includes animals
Correct Answer: B. Rationale: A food web consists of multiple
interconnected food chains, showing a more realistic flow of energy.
8. Which biome is characterized by permafrost and low-growing
vegetation?
A) Taiga
B) Tundra
C) Temperate deciduous forest
D) Grassland
, Correct Answer: B. Rationale: The tundra biome has a permanently
frozen subsoil layer known as permafrost, which limits plant growth.
9. What is the role of a decomposer in an ecosystem?
A) Produces energy from sunlight
B) Breaks down dead organic matter
C) Consumes primary producers
D) Regulates predator populations
Correct Answer: B. Rationale: Decomposers, like bacteria and fungi,
break down dead organisms and waste, returning nutrients to the soil.
10. Which of the following represents an organism's fundamental
niche?
A) The actual conditions it occupies
B) The full range of conditions it could theoretically occupy
C) Its role as a predator
D) Its physical habitat only
Correct Answer: B. Rationale: The fundamental niche is the entire set of
conditions under which an organism can survive and reproduce, while
the realized niche is the actual conditions it occupies due to
competition.
11. What type of succession occurs after a disturbance that leaves the
soil intact?
A) Primary succession
B) Secondary succession
C) Tertiary succession
D) Climax succession
Correct Answer: B. Rationale: Secondary succession occurs when a
