PCB 3043 - Exam 1 Questions with Correct Answers Latest Update 2025/2026
Ecology - Answers The scientific study of the relationships between organisms and their
environment
John Graunt - Answers Used simple mathematical populations to demonstrate that populations
are limited and cannot grow without restriction
Two Laws of Population Growth: - Answers 1. Populations have the potential to grow rapidly
2. They can't grow forever at high rates. Populations must be regulated such that rapid growth
is limited phenomenon
Sir Ronald Ross - Answers Worked as a military physician in India, demonstrated the malarial
oocysts in the gut tissue of female Anopheles mosquito
Doubling time - Answers The number of years needed to double a population, assuming a
constant rate of natural increase
Population - Answers A group of individuals that belong to the same species and live in the
same area
Growth rate equation - Answers Birth rate - Death rate
Demography - Answers The study of the age structure and growth rate of populations
Density - Answers The number of individuals in relation to the space or volume in which they
occur
Distribution - Answers The geographic and ecological range of a population
Dispersion - Answers The spacing of individuals with respect to one another
Mark-recapture method - Answers A sampling technique used to estimate wildlife populations;
individuals (numbering M) are captured, marked, and released;
we assume that they mix freely and completely with the rest of the population; then we capture
some individuals again, count the total number of individuals caught (n) and the number of
those that were marked previously (x)
Estimated population size - Answers N=nM/x; #marked/total number= #marked in
resample/#resampled
Population pyramids - Answers Show the number of individuals (or percent in different age
classes) going up and down, with males on the left and females on the right
, Per-capita rate - Answers Per individual rate
Per-capita birth rate (b) - Answers The probability of an individual having offspring during some
time period
Per-capita death rate - Answers The probability of an individual dying in a specified period of
time
dN/dt - Answers Population growth rate = population births - population deaths (bN-dN); change
in population size/change in time; N(b-d) or rN
What does r equal when the population is increasing? - Answers Positive
What does r equal when the population is decreasing? - Answers Negative
What does r equal when the population is stable? - Answers 0
Fecundity - Answers Reproductive output under ideal conditions, limited by genetics, not the
environment
Fertility - Answers The actual reproduction in a given environment. Note that it must be less or
equal to the fecundity
Immigration rate - Answers Number of individuals that join the population per unit time
Emigration rate - Answers Number of individuals that leave the population per unit time
Rate of population change per capita (per individual) - Answers r = births - deaths + immigration
- emigration
Exponential growth equation - Answers r or R sub 0 must be constant and either positive
(slopes up) or negative (slopes down)
Discrete growth - Answers All individuals pass through life stages at the same time, often
common in organisms affected by seasons; Nt+1 = Nt x R0
Continuous growth - Answers Individuals in a population are relatively independent in terms of
when they are born, reproduce, and die. This results in overlapping generations
Continuous exponential growth rate - Answers Nt = N0^ert or dN/dt = rN
Discrete exponential population growth rate - Answers Nt = N0 x R0^t
Per-capita growth equation - Answers (1/N) x (dN/dt) = r
Genetic bottleneck - Answers When a population severely declines due to environmental events
(e.g., disease or hurricanes) or human activities. Such events reduce the genetic variation of a
population. These population size reductions and the loss of genetic variation leave the
Ecology - Answers The scientific study of the relationships between organisms and their
environment
John Graunt - Answers Used simple mathematical populations to demonstrate that populations
are limited and cannot grow without restriction
Two Laws of Population Growth: - Answers 1. Populations have the potential to grow rapidly
2. They can't grow forever at high rates. Populations must be regulated such that rapid growth
is limited phenomenon
Sir Ronald Ross - Answers Worked as a military physician in India, demonstrated the malarial
oocysts in the gut tissue of female Anopheles mosquito
Doubling time - Answers The number of years needed to double a population, assuming a
constant rate of natural increase
Population - Answers A group of individuals that belong to the same species and live in the
same area
Growth rate equation - Answers Birth rate - Death rate
Demography - Answers The study of the age structure and growth rate of populations
Density - Answers The number of individuals in relation to the space or volume in which they
occur
Distribution - Answers The geographic and ecological range of a population
Dispersion - Answers The spacing of individuals with respect to one another
Mark-recapture method - Answers A sampling technique used to estimate wildlife populations;
individuals (numbering M) are captured, marked, and released;
we assume that they mix freely and completely with the rest of the population; then we capture
some individuals again, count the total number of individuals caught (n) and the number of
those that were marked previously (x)
Estimated population size - Answers N=nM/x; #marked/total number= #marked in
resample/#resampled
Population pyramids - Answers Show the number of individuals (or percent in different age
classes) going up and down, with males on the left and females on the right
, Per-capita rate - Answers Per individual rate
Per-capita birth rate (b) - Answers The probability of an individual having offspring during some
time period
Per-capita death rate - Answers The probability of an individual dying in a specified period of
time
dN/dt - Answers Population growth rate = population births - population deaths (bN-dN); change
in population size/change in time; N(b-d) or rN
What does r equal when the population is increasing? - Answers Positive
What does r equal when the population is decreasing? - Answers Negative
What does r equal when the population is stable? - Answers 0
Fecundity - Answers Reproductive output under ideal conditions, limited by genetics, not the
environment
Fertility - Answers The actual reproduction in a given environment. Note that it must be less or
equal to the fecundity
Immigration rate - Answers Number of individuals that join the population per unit time
Emigration rate - Answers Number of individuals that leave the population per unit time
Rate of population change per capita (per individual) - Answers r = births - deaths + immigration
- emigration
Exponential growth equation - Answers r or R sub 0 must be constant and either positive
(slopes up) or negative (slopes down)
Discrete growth - Answers All individuals pass through life stages at the same time, often
common in organisms affected by seasons; Nt+1 = Nt x R0
Continuous growth - Answers Individuals in a population are relatively independent in terms of
when they are born, reproduce, and die. This results in overlapping generations
Continuous exponential growth rate - Answers Nt = N0^ert or dN/dt = rN
Discrete exponential population growth rate - Answers Nt = N0 x R0^t
Per-capita growth equation - Answers (1/N) x (dN/dt) = r
Genetic bottleneck - Answers When a population severely declines due to environmental events
(e.g., disease or hurricanes) or human activities. Such events reduce the genetic variation of a
population. These population size reductions and the loss of genetic variation leave the
