BIO 212 Quiz 7 Questions and Answers Fully Solved Latest Version 2025-2026
What is Liebig's Law? - Answers Liebig's law of the minimum, often simply called Liebig's law or
the law of the minimum, is a principle developed in agricultural science by Carl Sprengel (1828)
and later popularized by Justus von Liebig. It states that growth is controlled not by the total
amount of resources available, but by the scarcest resource (limiting factor).
What is FACE? - Answers Pump CO2 into atmosphere around loblolly pine trees to increase
growth rate of trees. (7 years only, doesnt grow faster than control trees afterwards) Limiting
factor: soil nitrogen
What are reproductive rates? - Answers Crude reproductive rate: takes into account the number
of offspring
per some number of individuals in the population
• A more accurate way of determining birth rate is to estimate births of
female offspring per female, specifically those who have reached
reproductive age
What are fecundity tables? - Answers • Fecundity tables take into account
age-specific birth rates (bx) and
survivorship (lx)
• The sum of the lxbx values is the
net reproductive rate R0
Survival rates (sx
) represent
the proportion of individuals
that survive to the next age
class
sx = 1 - qx
Using this data, a population
projection table can be
constructed
,What are population projection tables? - Answers Like fecundity tables, these tables focus on
the reproductive output of
females
• The population size N(t) of any year is a function of the survivorship
(sx) of females in each age class plus the product of the age-specific
birth rates (bx) of females in each age class
Using sx and bx from the earlier table, the change in
population size N(t) can be estimated
The percent change in N(t) from period to period is the finite
multiplication rate (lambda)
Lambda = N(t+1)/N(t)
After year 5, this Population Projection Table shows squirrels
them increasing at a constant rate of 20% per year
◦ It remains constant because the squirrel population has reached a
stable age distribution
Age
Year (t)
012
Population growth (lambda) is a function of the age-specific survival
(sx) and birth (bx) rates
• The constant rate of increase of the population from year to year and
the stable age distribution are because of the constant survival and
birth rates through time
Once lambda is known, the population size can be projected to any
year in the future using the equation:
• N(t) = N(0)lambdat
, • As long as lambda is greater than one, the population will grow
• As long as birth (bx) and mortality (sx) remain constant, the population can
grow rapidly
At what rate do populations usually grow and why? - Answers All populations have the potential
to grow exponentially
As we have seen, population growth is a function of the difference
between birth and death rates
To develop an exponential growth model we can say that b - d = r
Then the change in population size over time (dN/dt) = rN
◦ As long as r is positive the population can grow exponentially
Why dont populations always grow exponentially? - Answers Population dynamics represent the
combined outcome of many
individual probabilities, including:
• Variations in bx and sx
, which we call demographic stochasticity
• Variations in environmental conditions, we call environmental stochasticity
What are small populations susceptible to? - Answers Genetic drift
Inbreeding
In plants, small populations have reduced visitations by pollinators =
reduced seed set
In animals, social structure in leks (communal mating grounds) can be
disrupted
Allee effect: when population density becomes low enough that
otherwise healthy males and females can't find one anothe
What is Intraspecific population regulation? - Answers • Populations can't grow exponentially
forever because of various
forms of stochasticity
What is Liebig's Law? - Answers Liebig's law of the minimum, often simply called Liebig's law or
the law of the minimum, is a principle developed in agricultural science by Carl Sprengel (1828)
and later popularized by Justus von Liebig. It states that growth is controlled not by the total
amount of resources available, but by the scarcest resource (limiting factor).
What is FACE? - Answers Pump CO2 into atmosphere around loblolly pine trees to increase
growth rate of trees. (7 years only, doesnt grow faster than control trees afterwards) Limiting
factor: soil nitrogen
What are reproductive rates? - Answers Crude reproductive rate: takes into account the number
of offspring
per some number of individuals in the population
• A more accurate way of determining birth rate is to estimate births of
female offspring per female, specifically those who have reached
reproductive age
What are fecundity tables? - Answers • Fecundity tables take into account
age-specific birth rates (bx) and
survivorship (lx)
• The sum of the lxbx values is the
net reproductive rate R0
Survival rates (sx
) represent
the proportion of individuals
that survive to the next age
class
sx = 1 - qx
Using this data, a population
projection table can be
constructed
,What are population projection tables? - Answers Like fecundity tables, these tables focus on
the reproductive output of
females
• The population size N(t) of any year is a function of the survivorship
(sx) of females in each age class plus the product of the age-specific
birth rates (bx) of females in each age class
Using sx and bx from the earlier table, the change in
population size N(t) can be estimated
The percent change in N(t) from period to period is the finite
multiplication rate (lambda)
Lambda = N(t+1)/N(t)
After year 5, this Population Projection Table shows squirrels
them increasing at a constant rate of 20% per year
◦ It remains constant because the squirrel population has reached a
stable age distribution
Age
Year (t)
012
Population growth (lambda) is a function of the age-specific survival
(sx) and birth (bx) rates
• The constant rate of increase of the population from year to year and
the stable age distribution are because of the constant survival and
birth rates through time
Once lambda is known, the population size can be projected to any
year in the future using the equation:
• N(t) = N(0)lambdat
, • As long as lambda is greater than one, the population will grow
• As long as birth (bx) and mortality (sx) remain constant, the population can
grow rapidly
At what rate do populations usually grow and why? - Answers All populations have the potential
to grow exponentially
As we have seen, population growth is a function of the difference
between birth and death rates
To develop an exponential growth model we can say that b - d = r
Then the change in population size over time (dN/dt) = rN
◦ As long as r is positive the population can grow exponentially
Why dont populations always grow exponentially? - Answers Population dynamics represent the
combined outcome of many
individual probabilities, including:
• Variations in bx and sx
, which we call demographic stochasticity
• Variations in environmental conditions, we call environmental stochasticity
What are small populations susceptible to? - Answers Genetic drift
Inbreeding
In plants, small populations have reduced visitations by pollinators =
reduced seed set
In animals, social structure in leks (communal mating grounds) can be
disrupted
Allee effect: when population density becomes low enough that
otherwise healthy males and females can't find one anothe
What is Intraspecific population regulation? - Answers • Populations can't grow exponentially
forever because of various
forms of stochasticity
