Biology 301 - Ecology and Evolution - Chapter 12 Exam Questions and Verified
Answers/Accurate Solutions| New Update Already Graded A+
What is demography? The study of (the structure and growth of) populations
What type of techniques does demography use to predict the growth of populations(both
natural and laboratory)? Mathematical techniques.
What basic processes have direct effects on population size? Births & immigration (cause
population increase) along with Deaths and Emigration (cause population decrease). ∆N=(B+I)
minus (D+E).
What does a geometric (discrete) growth model represent? A model of population growth
that compares population sizes at regular time intervals, showing how populations with
discrete generations and discrete reproductive bouts fluctuate in seasonal patterns of
population increase and decrease.
What is the equation for geometric (discrete) growth model for multiple time intervals? N₍t₎
= N₍₀₎λ⁽ᵗ⁾
What does lambda (λ) in the geometric (discrete) growth model represent? It is the ratio of
population size at any time to the population size 1 time unit earlier, or the "per capita growth
rate" / "finite rate of increase".
What happens when λ=1? The population is constant.
What happens when λ<1? The population is decreasing.
What happens when λ>1? The population is increasing.
, What does the exponential (continuous) growth model represent? A model of population
growth in which the population increases continuously at an exponential rate, has overlapping
generations with year round reproduction and exhibits smooth curve of population increase as
a function of time.
What is the equation for exponential (continuous) growth model? N₍t₎ = N₍₀₎e⁽ʳᵗ⁾ where N = #
of individuals after t time units, N₍₀₎ = the initial population size, r = exponential growth rate /
instantaneous rate of increase, t = time units and e = base of the natural logs (~2.72).
What is the conversion for growth rates? λ=e⁽ʳ⁾ thus r=ln(λ).
What happens when r=0? The population is constant.
What happens when r<0? The population is decreasing.
What happens when r>0? The population is increasing.
Definition of density independent: Factors that limit population size regardless of
population's density, such as climatic events.
Definition of density dependent: Factors that affect population size in relation to the
population's density.
Two types of density dependence and their defintions: 1. Negative density dependence =
when the rate of population growth decreases as population density increases. 2. Positive
density dependence = when the rate of population growth increases as population density
increases.
Common factors of negative density dependence: Most common factors causing negative
density dependence are limiting resources (food, nesting sites, physical space). As population's
Answers/Accurate Solutions| New Update Already Graded A+
What is demography? The study of (the structure and growth of) populations
What type of techniques does demography use to predict the growth of populations(both
natural and laboratory)? Mathematical techniques.
What basic processes have direct effects on population size? Births & immigration (cause
population increase) along with Deaths and Emigration (cause population decrease). ∆N=(B+I)
minus (D+E).
What does a geometric (discrete) growth model represent? A model of population growth
that compares population sizes at regular time intervals, showing how populations with
discrete generations and discrete reproductive bouts fluctuate in seasonal patterns of
population increase and decrease.
What is the equation for geometric (discrete) growth model for multiple time intervals? N₍t₎
= N₍₀₎λ⁽ᵗ⁾
What does lambda (λ) in the geometric (discrete) growth model represent? It is the ratio of
population size at any time to the population size 1 time unit earlier, or the "per capita growth
rate" / "finite rate of increase".
What happens when λ=1? The population is constant.
What happens when λ<1? The population is decreasing.
What happens when λ>1? The population is increasing.
, What does the exponential (continuous) growth model represent? A model of population
growth in which the population increases continuously at an exponential rate, has overlapping
generations with year round reproduction and exhibits smooth curve of population increase as
a function of time.
What is the equation for exponential (continuous) growth model? N₍t₎ = N₍₀₎e⁽ʳᵗ⁾ where N = #
of individuals after t time units, N₍₀₎ = the initial population size, r = exponential growth rate /
instantaneous rate of increase, t = time units and e = base of the natural logs (~2.72).
What is the conversion for growth rates? λ=e⁽ʳ⁾ thus r=ln(λ).
What happens when r=0? The population is constant.
What happens when r<0? The population is decreasing.
What happens when r>0? The population is increasing.
Definition of density independent: Factors that limit population size regardless of
population's density, such as climatic events.
Definition of density dependent: Factors that affect population size in relation to the
population's density.
Two types of density dependence and their defintions: 1. Negative density dependence =
when the rate of population growth decreases as population density increases. 2. Positive
density dependence = when the rate of population growth increases as population density
increases.
Common factors of negative density dependence: Most common factors causing negative
density dependence are limiting resources (food, nesting sites, physical space). As population's
