Chapter 12 Lecture 1

Question 1

under ideal conditions…

Answer 1

populations can grow rapidly

Question 2

demography

Answer 2

the study of populations

Question 3

growth rate

Answer 3

in a population, the number of new individuals that are produced per unit of time minus the number of individuals that die

Question 4

Intrinsic growth rate (r)

Answer 4

the highest possible per capita growth rate for a population.

Question 5

what do individuals experience under ideal conditions

Answer 5

maximum r (i.e., maximum reproductive rates and minimum death rates

Question 6

what does the strength of a reproductive population depend on

Answer 6

1. the number of individuals of reproductive age
2. the availability of resources such as food and mates
3. the presence or absence of predators, disease, etc.

Question 7

how may individuals be added to populations

Answer 7

1. continuous reproduction

2. discrete reproductive periods

Question 8

what does the periodicity with which offspring are produced result in

Answer 8

important differences in the way in which population growth is conceptualized mathematically

Question 9

in many species, young are added only during certain times of the year during…

Answer 9

discrete reproductive periods - such populations undergo geometric growth

Question 10

in geometric growth

Answer 10

the rate of increase is proportional to the number of individuals present in the population at the beginning of the discrete reproductive period

Question 11

what is the typical form of population growth in the wild

Answer 11

geometric growth

Question 12

species that reproduce continually

Answer 12

they can add young at any time of the year

Question 13

what do populations with continual reproduction undergo

Answer 13

exponential growth

Question 14

exponential growth model

Answer 14

a model of population growth in which the population increases continuously at an exponential rate

Question 15

what equation describes the exponential growth model

Answer 15

Nt+ N0e^rt

Question 16

Nt

Answer 16

future population size

Question 17

N0

Answer 17

current population size

Question 18

r

Answer 18

intrinsic growth rate

Question 19

t

Answer 19

time over which a population grows

Question 20

e

Answer 20

2.7183

Question 21

J-shaped curve

Answer 21

the shape of the exponential growth when graphed

Question 22

the rate of a population’s growth at any point in time is the derivative of this equation

Answer 22

dN/dt = rN

Question 23

e^r

Answer 23

the factor by which the population increases during each unit of time, and is sometimes symbolized with a lambda

Question 24

exponential growth

Answer 24

results in a continuous curve of increase (or decrease, when the rt term is negative) whose slope varies in direct relation to the size of the population

Question 25

the rate of increase of a population undergoing exponential growth at a particular instant in time, the instantaneous rate of increase =

Answer 25

dN/dt = rN

Question 26

dN/dt = rN | this equation encompasses two principles (A)

Answer 26

1. the exponential growth rate (r) expresses the population increase (or decrease) on a per individual basis

Question 27

dN/dt = rN | this equation encompasses two principles (B)

Answer 27

2. the rate of increase (dN/dt) varies in direct proportion to the size of the population (N)

Question 28

the rate of the change in population size equals

Answer 28

the contribution of each individual to population growth times the number of individuals in the population

Question 29

the individual contribution (per capita) to population growth is the difference between

Answer 29

the birth rate (b) and the death rate (d) calculated on a per capita basis

Question 30

dN/dt = bN - dN or

Answer 30

dN/dt = (b-d)N

Question 31

since r is the difference between birth rate and death rate (b-d),

Answer 31

dN/dt (rate of increase) = rN

Question 32

when the death rate exceeds the birth rate...

Answer 32

r is negative, and the population declines

Question 33

what equation represents exponential population growth

Answer 33

Nt = N0e^rt

Question 34

when young are added to populations during certain time frames (discrete population growth), what is the best way to represent growth

Answer 34

geometric growth model

Question 35

which growth is most common among wild populations

Answer 35

discrete

Question 36

overall, within each year, the population growth rate of a discretely growing population varies with

Answer 36

seasonal changes in the balance of birth and death processes

Question 37

seasonal

Answer 37

discrete

Question 38

why do populations initially grow slowly

Answer 38

because there is a small number of reproductive individuals

Question 39

what does growth rate increase with

Answer 39

the number of reproductive individuals

Question 40

what kind of breeding seasons do most species have

Answer 40

discrete

Question 41

geometric growth model

Answer 41

a model of population growth that compares population sizes at regular time intervals

Question 42

expressed as a ratio of a population's size is one year to its size in the preceding year (lambda)

Answer 42

geometric growth model

Question 43

when lambda is greater than 1

Answer 43

population size has increased

Question 44

when lambda is less than 1

Answer 44

population size has decreased

Question 45

lambda cannot be...

Answer 45

negative

Question 46

growth in populations with discrete breeding seasons is treated somewhat differently than...

Answer 46

growth in populations with continual growth

Question 47

the size of the populations with discrete breeding seasons must be measured consistently at...

Answer 47

a particular time of the year to have any meaning

Question 48

when populations are augmented periodically...

Answer 48

it is most convenient to express the growth rate as a ration of the population in one year to that of the preceding year (N1/N0)

Question 49

demographers have assigned lambda to N1/N0 and call it

Answer 49

the geometric growth rate

Question 50

lambda =

Answer 50

N1/N0

Question 51

lambda represents

Answer 51

a factor of population increase

Question 52

if one wants, then to project the size of a population into the future (t=1), it could be written as

Answer 52

N(t+1) = N (1) lambda

Question 53

in order to project the growth of a population...

Answer 53

the original number N(0) is multiplied by the geometric growth rate lambda once for each unit of time passed

Question 54

N(t) =

Answer 54

N(0) lambda^t

Question 55

the equation for geometric growth is identical to the one for exponential growth, except that...

Answer 55

lambda, the geometric growth rate, takes the place of e^r (the amount of exponential growth accomplished in one time period)

Question 56

N(t) =

Answer 56

N(0) lambda ^t

Question 57

exponential and geometric growth models are identical except

Answer 57

e^r takes the place of lambda

Question 58

when a population is decreasing

Answer 58

lambda < 1 | r < 0

Question 59

when a population is constant

Answer 59

``` lambda = 1 r = 0 ```

Question 60

when a population is increasing

Answer 60

lambda > 1 | r >0

Question 61

decreasing populations have...

Answer 61

negative exponential growth rates and geometric growth rates greater than 0 but less than 1

Question 62

increasing populations have

Answer 62

positive exponential growth rates and geometric growth rates that are greater than 1

Question 63

doubling time

Answer 63

the time required for a population to double in size

Question 64

how can doubling time be estimated

Answer 64

by rearranging the exponential growth model

Question 65

Nt = N0e^rt --->

Answer 65

e^rt = Nt/N0

Question 66

When a population doubles, Nt/N0 =

Answer 66

2

Question 67

for the geometric model, the equation for doubling time is

Answer 67

t2 = loge2/loge(lambda)