Deck 10: Population Growth

Question 1

Movement in and out of a population does not occur in a(n)________ population.

Answer 1

closed

Question 2

A population eventually goes ________ when its population growth (r)remains negative without reversing.

Answer 2

extinct

Question 3

The ________ birthrate is expressed as the births per 1000 individuals per unit of time.

Answer 3

crude

Question 4

The per capita death rate (d)________ with population size.

Question 5

The maximum sustainable population size for the prevailing environment is called the ________.

Question 6

There is no change in population size when the instantaneous per capita rate of growth (r)is equal to ________.

Question 7

A type ________ survivorship curve is typical of populations in which the mortality rate of juveniles is very high.

Question 8

To obtain a clear and systematic picture of mortality and survival within a population, ecologists construct ________.

Question 9

A ________ life table is constructed by sampling the population to obtain a distribution of age classes during a single time period.

Question 10

Explain the trade-off between resistance and resilience for a large-bodied animal.

Question 11

________ stochasticity is the random variation in birth and death rates that occur in populations from year to year due to natural disasters and other annual variations in the environment.

Question 12

What characteristics of a population must we know, in order to predict growth over time?

Question 13

A mortality curve plots mortality rate (qₓ)against ________.

Question 14

________ is the study of populations.

Question 15

Demographic ________ is the random variation in birth and death rates that occur in populations from year to year.

Question 16

A group of individuals born in the same period of time is called a(n)________.

Question 17

The net reproductive rate (R₀)is equal to ________ when females, on average, replace themselves in a population.

Question 18

Adult birds exhibit a type ________ survivorship curve.

Question 19

Ecologists develop a ________ life table to follow the fate of a group of individuals, all born at a given time, from birth to death.

Question 20

________ refers to the rate at which the number of individuals in a population increases or decreases with time.

Question 21

A population that is decreasing in size has an intrinsic rate of population growth (r)that is

A)< 0.
B)= 0.
C)> 0.
D)> 1.

Question 22

Most life tables have been constructed for

A)short-lived plants.
B)insects.
C)long-lived vertebrates.
D)short-lived mammals.

Question 23

A systematic compilation of mortality and survival data for a population is called a(n)

A)age pyramid.
B)cohort group.
C)life table.
D)probability summary.

Question 24

Which of the following is incorrect?

A)sₓ is the average survival rate of the population.
B)l is the rate of population growth.
C)N(t)is the total population size for a given year.
D)bₓ is the age-specific birthrate.

Question 25

Life ________ refers to the average number of years that an individual is expected to live from the time of his or her birth.

Question 26

A fecundity table includes all the following information, EXCEPT

A)age-specific birthrates.
B)survivorship.
C)net reproductive rate.
D)age.

Question 27

Using the geometric model, if N(0)= 30 and λ = 1.20, what is the population size for year one (N₁)?

A)25
B)28.8
C)30
D)36

Question 28

Colonizing populations generally exhibit ________ population growth while they establish in a new environment.

A)exponential
B)logistic
C)tangential
D)dynamic

Question 29

A ________ survivorship curve is typical of humans and other mammals, in which survival rate is high throughout the life span followed by heavy mortality at the end.

A)type I
B)type II
C)type III
D)type IV

Question 30

The average number of female offspring born to a female over her lifetime is the

A)crude birth rate.
B)age-specific birth rate.
C)gross reproductive rate.
D)net reproductive rate.

Question 31

In a life table, the value lₓ represents the

A)age-specific mortality rate.
B)age-specific life expectancy.
C)age-specific mortality.
D)the probability at birth of surviving to any given age.

Question 32

Which of the following equations is used to calculate generation time?

A)N(t)= b - d
B)Tc = ∑xlₓbₓ/∑lₓbₓ
C)N(t)= N(0)eʳᵗ
D)dN/dt = rN

Question 33

The life table is most useful in studying all the following areas of plant demography, EXCEPT

A)life cycles of perennial plants.
B)life cycles of annual plants.
C)seedling mortality and survival.
D)population dynamics of perennial plants marked as seedlings.

Question 34

The ________ equals the number of births per female of age x.

A)crude birth rate
B)age-specific birth rate
C)gross reproductive rate
D)net reproductive rate

Question 35

A ________ is the mean time between when a female is born and when she reproduces.

A)population cycle
B)net reproductive rate
C)generation time
D)fecundity parameter

Question 36

Survivorship curves plot ________ against x.

A)dₓ
B)lₓ
C)log lₓ
D)qₓ

Question 37

Which of the following equations reflects the exponential model of population growth?

A)N(t)= b - d
B)Tc = ∑xlₓbₓ/∑lₓbₓ
C)N(t)= N(0)eʳᵗ
D)dN/dt = rN

Question 38

The ________ effect is the decline in either reproduction or survival under conditions of low population density.

Question 39

________ populations are more susceptible to both demographic and environmental stochasticity than ________ populations.

Question 40

If population size N(t)is plotted as a linear function of time (t), the ________ of the resulting line will remain constant between any two points.

Question 41

Exponential growth is characteristic of populations that inhabit favourable environments at high densities.

Question 42

Immigration and emigration occurs within an open population.

Question 43

A small population is at a greater risk of extinction because

A)there is less competition within the population.
B)of an increase in the genetic diversity within the population.
C)most of the individuals would likely die in a stochastic event (e.g., wildfire).
D)females can no longer reproduce.

Question 44

When a population is stable, the net reproductive rate (R₀)is equal to zero.

Question 45

The exponential model of population growth assumes

A)that essential resources are unlimited.
B)a changeable environment.
C)that all individuals in the population are the same age.
D)a constant mortality rate throughout the population.

Question 46

The net reproductive rate represents the number of births per 1000 population per unit of time.

Question 47

A population's ________ factors determine demographic stochasticity.

A)extrinsic
B)intrinsic
C)independent
D)predicted

Question 48

The instantaneous per capita rate of growth (r)of a stable population is equal to zero.

Question 49

There are two general types of survivorship curves.

Question 50

A population in which λ equals one has reached a stable-age distribution.

Question 51

The rate at which a population returns to an equilibrium after a disturbance is known as

A)tolerance range.
B)return time.
C)resistance.
D)resilience.

Question 52

As population size (N)increases

A)birth rate increases.
B)birth rate decreases.
C)death rate decreases.
D)carrying capacity increases.

Question 53

In a given life table, x represents the age classes of that population.

Question 54

Exponential population growth does not occur in natural populations.

Question 55

In logistic growth, the level at which population growth ceases is referred to as the

A)threshold of security.
B)Malthusian parameter.
C)saturation point.
D)carrying capacity.

Question 56

The probability of survival and death usually varies with age.

Question 57

An equation in which the derivative appears on the left-hand side is referred to as a

A)calculation.
B)tangential equation.
C)differential equation.
D)derivative equation.

Question 58

A cohort refers to a group of individuals born in the same period of time.

Question 59

A time-specific life table is easier to create and more accurate than a dynamic life table.

Question 60

A leading cause of current population extinctions is

A)global warming.
B)habitat destruction.
C)hunting.
D)diseases.

Question 61

Because birth and death rates are not constant, tables and models developed by a demographer may have limited relevance to real populations.

Question 62

Discuss five factors known to cause extinction. Which of these factors is considered the leading cause of current extinctions and why?

Question 63

Explain how λ is used by demographers to predict the future size of a population.

Question 64

Genetic drift occurs at a faster rate in a large population than in a small population.

Question 65

What is the difference between exponential growth and logistic growth? Under what ecological conditions does each occur?

Question 66

Compare and contrast the two basic types of life tables. Discuss the advantages and disadvantages of each.

Question 67

What is the significance of constructing a life table to an ecologist? What information is required to develop a life table and what is this information used for?

Question 68

The introduction of a novel organism into an ecosystem can lead to extinction/s of the natural population/s.

Question 69

The carrying capacity (K)of a population can vary depending on the supply of resources.

Question 70

Discuss some of the important issues involved when trying to determine Earth's carrying capacity (K)for humans. Why is it difficult to calculate K for the human population?

Question 71

Life expectancy (e)is the same for an individual regardless of age.

Question 72

Illustrate three types of survivorship curves and give examples of each. What factors cause the three different types to appear in nature?

Question 73

Discuss two stochastic processes and describe how each influences population dynamics.

Question 74

What is the Allee effect? Give several examples that illustrate the potential catastrophic impact of small size on population persistence.

Question 75

Explain a population cycle. What factors contribute to this phenomenon?