PCB3044 Principles of Ecology Exam 2 Study Guide 2026 – UCF
1. Which type of survivorship curve is characterized by high age-specific survival
probability in early and middle life, followed by a rapid decline in survival in
later life?
A. Type III
B. Type II
C. Type I
D. Type IV
Answer: C
Rationale: Type I curves are typical of species that produce few offspring but provide them
with good care, such as humans and large mammals.
2. In the logistic growth equation, dN/dt = rN(1 - N/K), what does ‘K’ represent?
A. Intrinsic rate of increase
B. Population size
C. Carrying capacity
D. Generation time
Answer: C
Rationale: K represents the carrying capacity, which is the maximum population size that
a particular environment can sustain.
,3. An organism that reproduces only once in its lifetime is described as:
A. Iteroparous
B. Altricial
C. Viviparous
D. Semelparous
Answer: D
Rationale: Semelparity refers to a reproductive strategy where an organism invests all its
energy into a single reproductive event before dying.
4. Which of the following is a density-independent factor that can limit
population growth?
A. Competition for food
B. Disease transmission
C. Predation pressure
D. A catastrophic flood
Answer: D
Rationale: Density-independent factors, like weather or natural disasters, affect
populations regardless of their size or density.
5. The set of conditions under which a species can potentially survive and
reproduce in the absence of interactions with other species is called its:
A. Realized niche
B. Fundamental niche
C. Habitat
D. Microenvironment
Answer: B
Rationale: The fundamental niche is the full range of environmental conditions a species
can occupy without the influence of competition or predation.
, 6. In a metapopulation, what process prevents small sub-populations from
going extinct by bringing in new individuals?
A. The Allee effect
B. The rescue effect
C. Character displacement
D. Competitive exclusion
Answer: B
Rationale: The rescue effect occurs when immigrants from larger or more stable patches
prevent a smaller population from going extinct.
7. Which interaction is characterized as (+/-), where one organism benefits and
the other is harmed but usually not killed immediately?
A. Predation
B. Parasitism
C. Mutualism
D. Commensalism
Answer: B
Rationale: Parasites derive nourishment from their hosts, harming them over time but
typically not killing them as quickly as a predator would.
8. If two species compete for the exact same limiting resource, one will
eventually outcompete and eliminate the other. This is known as:
A. Resource partitioning
B. Niche overlap
C. Competitive exclusion principle
D. Character displacement
Answer: C
Rationale: Gause’s law or the competitive exclusion principle states that two species
competing for the same limiting resource cannot coexist.
1. Which type of survivorship curve is characterized by high age-specific survival
probability in early and middle life, followed by a rapid decline in survival in
later life?
A. Type III
B. Type II
C. Type I
D. Type IV
Answer: C
Rationale: Type I curves are typical of species that produce few offspring but provide them
with good care, such as humans and large mammals.
2. In the logistic growth equation, dN/dt = rN(1 - N/K), what does ‘K’ represent?
A. Intrinsic rate of increase
B. Population size
C. Carrying capacity
D. Generation time
Answer: C
Rationale: K represents the carrying capacity, which is the maximum population size that
a particular environment can sustain.
,3. An organism that reproduces only once in its lifetime is described as:
A. Iteroparous
B. Altricial
C. Viviparous
D. Semelparous
Answer: D
Rationale: Semelparity refers to a reproductive strategy where an organism invests all its
energy into a single reproductive event before dying.
4. Which of the following is a density-independent factor that can limit
population growth?
A. Competition for food
B. Disease transmission
C. Predation pressure
D. A catastrophic flood
Answer: D
Rationale: Density-independent factors, like weather or natural disasters, affect
populations regardless of their size or density.
5. The set of conditions under which a species can potentially survive and
reproduce in the absence of interactions with other species is called its:
A. Realized niche
B. Fundamental niche
C. Habitat
D. Microenvironment
Answer: B
Rationale: The fundamental niche is the full range of environmental conditions a species
can occupy without the influence of competition or predation.
, 6. In a metapopulation, what process prevents small sub-populations from
going extinct by bringing in new individuals?
A. The Allee effect
B. The rescue effect
C. Character displacement
D. Competitive exclusion
Answer: B
Rationale: The rescue effect occurs when immigrants from larger or more stable patches
prevent a smaller population from going extinct.
7. Which interaction is characterized as (+/-), where one organism benefits and
the other is harmed but usually not killed immediately?
A. Predation
B. Parasitism
C. Mutualism
D. Commensalism
Answer: B
Rationale: Parasites derive nourishment from their hosts, harming them over time but
typically not killing them as quickly as a predator would.
8. If two species compete for the exact same limiting resource, one will
eventually outcompete and eliminate the other. This is known as:
A. Resource partitioning
B. Niche overlap
C. Competitive exclusion principle
D. Character displacement
Answer: C
Rationale: Gause’s law or the competitive exclusion principle states that two species
competing for the same limiting resource cannot coexist.
