ECCB-403 Final Exam 2026 Questions
and Answers
Allee Effects - Correct answer-Population growth rates that decrease below
replacement level at low population density, potentially leading to extinction.
Balance of Nature - Correct answer-The belief that natural populations and
communities exist in a stable equilibrium and maintain that equilibrium in the
absence of human interference.
Density-Dependent Rate - Correct answer-As population density rises, births or
immigration decrease or deaths or emigration increase, and consequently a graph
of population density versus the rate will have a positive or negative slope.
Density-Independent Rate - Correct answer-As population density rises, the rate
does not change in any systematic manner, so that a graph of population density
versus the rate will have a slope of zero.
Limiting Factor - Correct answer-A factor is defined as limiting if a change in the
factor produces a change in average or equilibrium density.
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,Metapopulations - Correct answer-Local populations in patches that are linked
together by dispersal among the patches, driven by colonization and extinction
dynamics.
Regulating Factor - Correct answer-A factor is defined as potentially regulating if
the percentage of mortality caused by the factor increases with population density
or if per capita reproductive rate decreases with population density.
Self-Thinning Rule - Correct answer-The prediction that the regression of
organism size versus population density has a slope of -1.5 for plants and animals
that have plastic growth rates and variable adult size.
Sink Population - Correct answer-Local populations in which the rate of
production is below replacement level so that extinction is inevitable without a
source of immigrants.
Source Populations - Correct answer-Local populations in which the rate of
production exceeds replacement so that individuals emigrate to surrounding
populations.
Population Regulation is important for: - Correct answer-Conservation, Land
Management, and Fisheries.
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,We can make two fundamental observations about populations of any plant or
animal.
The first observation is that: - Correct answer-Abundance varies from place to
place; there are some "good" habitats where the species is, on the average,
common and some "poor" habitats where it is, on the average, rare.
We can make two fundamental observations about populations of any plant or
animal.
The second observation is that: - Correct answer-NO population goes on increasing
without limit, and the problem is to find out what prevents unlimited increase in
low- and high-density populations.
We can make two fundamental observations about populations of any plant or
animal.
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, The second observation is that no population goes on increasing without limit, and
the problem is to find out what prevents unlimited increase in low- and high-
density populations.
This is the problem of explaining: - Correct answer-Fluctuations in Numbers!
Figure 14.1 illustrates this!
A population in a closed system will increase until it reaches an equilibrium point
at which: - Correct answer-Per Capita Birth rate = Per Capita Death Rate
A population in a closed system1 will increase until it reaches an equilibrium point
at which:
Per Capita Birth rate = Per Capita Death Rate
Figure 14.2 illustrates three possible ways in which this equilibrium may be
defined.
©COPYRIGHT 2025, ALL RIGHTS RESERVED 4
and Answers
Allee Effects - Correct answer-Population growth rates that decrease below
replacement level at low population density, potentially leading to extinction.
Balance of Nature - Correct answer-The belief that natural populations and
communities exist in a stable equilibrium and maintain that equilibrium in the
absence of human interference.
Density-Dependent Rate - Correct answer-As population density rises, births or
immigration decrease or deaths or emigration increase, and consequently a graph
of population density versus the rate will have a positive or negative slope.
Density-Independent Rate - Correct answer-As population density rises, the rate
does not change in any systematic manner, so that a graph of population density
versus the rate will have a slope of zero.
Limiting Factor - Correct answer-A factor is defined as limiting if a change in the
factor produces a change in average or equilibrium density.
©COPYRIGHT 2025, ALL RIGHTS RESERVED 1
,Metapopulations - Correct answer-Local populations in patches that are linked
together by dispersal among the patches, driven by colonization and extinction
dynamics.
Regulating Factor - Correct answer-A factor is defined as potentially regulating if
the percentage of mortality caused by the factor increases with population density
or if per capita reproductive rate decreases with population density.
Self-Thinning Rule - Correct answer-The prediction that the regression of
organism size versus population density has a slope of -1.5 for plants and animals
that have plastic growth rates and variable adult size.
Sink Population - Correct answer-Local populations in which the rate of
production is below replacement level so that extinction is inevitable without a
source of immigrants.
Source Populations - Correct answer-Local populations in which the rate of
production exceeds replacement so that individuals emigrate to surrounding
populations.
Population Regulation is important for: - Correct answer-Conservation, Land
Management, and Fisheries.
©COPYRIGHT 2025, ALL RIGHTS RESERVED 2
,We can make two fundamental observations about populations of any plant or
animal.
The first observation is that: - Correct answer-Abundance varies from place to
place; there are some "good" habitats where the species is, on the average,
common and some "poor" habitats where it is, on the average, rare.
We can make two fundamental observations about populations of any plant or
animal.
The second observation is that: - Correct answer-NO population goes on increasing
without limit, and the problem is to find out what prevents unlimited increase in
low- and high-density populations.
We can make two fundamental observations about populations of any plant or
animal.
©COPYRIGHT 2025, ALL RIGHTS RESERVED 3
, The second observation is that no population goes on increasing without limit, and
the problem is to find out what prevents unlimited increase in low- and high-
density populations.
This is the problem of explaining: - Correct answer-Fluctuations in Numbers!
Figure 14.1 illustrates this!
A population in a closed system will increase until it reaches an equilibrium point
at which: - Correct answer-Per Capita Birth rate = Per Capita Death Rate
A population in a closed system1 will increase until it reaches an equilibrium point
at which:
Per Capita Birth rate = Per Capita Death Rate
Figure 14.2 illustrates three possible ways in which this equilibrium may be
defined.
©COPYRIGHT 2025, ALL RIGHTS RESERVED 4
