Chapter #10 – Population Growth
(pg. 204 – 221)
Statistical Results – Biased Coin-flipping
Tuesday’s Lab

Thursday’s Lab

= 18.06
0.05, 1,4
2
2
0.05, 1,4
= 0.86
Reject Null Hypothesis
Accept Null Hypothesis
(Statistically Significant)
(No Difference)
(P < 0.05)
(P > 0.05)
20.05, 2,8= 7.28
Reject Null Hypothesis
(Statistically Significant)
(P < 0.05)
Chapter #10 – Population Growth
(pg. 204 – 221)
10.1
Population Growth Reflects the Difference
Between Birth and Death.
10.2 Life Tables Provide a Schedule of AgeSpecific Mortality and Survival.
10.3 Different Life Tables Reflect Different
Approaches to Defining Cohorts and Age
Structure.
10.4 Life Tables Provide Data for Mortality and
Survivorship Curves.
Chapter #10 – Population Growth
(pg. 204 – 221)
10.2 Life Tables Provide a Schedule of AgeSpecific Mortality and Survival.
Life Tables provide an age-specific
account of mortality. The
construction of a life table begins
with a cohort - a group of individuals
born in the same period of time.
Chapter #10 – Population Growth
(pg. 204 – 221)
10.2 Life Tables Provide a Schedule of AgeSpecific Mortality and Survival.
x
0
1
2
3
4
5
nx .
530
159
80
48
21
5
Chapter #10 – Population Growth
(pg. 204 – 221)
10.2 Life Tables Provide a Schedule of AgeSpecific Mortality and Survival.
x
nx .
0-1 530
1-2 159
2-3 80
3-4 48
4-5 21
5-6
5
Gray Squirrels
(Sciurus carolinensis)
Chapter #10 – Population Growth
(pg. 204 – 221)
10.2 Life Tables Provide a Schedule of AgeSpecific Mortality and Survival.
x
nx
lx = the probability
at birth of surviving
to any given age.
lx .
0-1 530 1.00
1-2 159 0.30
2-3 80 0.15
3-4 48 0.09
4-5 21 0.04
5-6
5 0.01
159/530
Chapter #10 – Population Growth
(pg. 204 – 221)
10.2 Life Tables Provide a Schedule of AgeSpecific Mortality and Survival.
x
nx
dx .
0-1 530 371
1-2 159 79
2-3 80 32
3-4 48 27
4-5 21 16
5-6
5
5
530 - 159
159 - 80
dx = an estimate of
age-specific
mortality. This is
the number of
individuals that died
during any given
time interval.
Chapter #10 – Population Growth
(pg. 204 – 221)
10.2 Life Tables Provide a Schedule of AgeSpecific Mortality and Survival.
x
nx
dx
0-1 530 371
1-2 159 79
2-3 80 32
3-4 48 27
4-5 21 16
5-6
5
5
qx .
0.70
0.50
0.40
0.55
0.75
1.00
qx = an estimate of
age-specific
371/530
mortality.
79/159
Chapter #10 – Population Growth
(pg. 204 – 221)
10.2 Life Tables Provide a Schedule of AgeSpecific Mortality and Survival.
Chapter #10 – Population Growth
(pg. 204 – 221)
Locations
Falls City Cemetery
Fircrest (Monmouth Cemetery
Crystal Lake Cemetery (Corvallis)
Females
Born Before 1900
Born After 1900
Males
Born Before 1900
Born After 1900
Age
Class
f (x)
d (x)
l (x)
1
121
Y
1000
2
q (x)
Age
Class
f (x)
12
22
16
13
31
3
16
14
32
4
26
15
19
5
24
16
23
6
20
17
18
7
29
18
8
8
26
19
0
9
21
20
0
10
10
21
0
11
19
22
0
Total
X
d (x)
l (x)
q (x)
Z
W
0.0
Chapter #10 – Population Growth
(pg. 204 – 221)
10.3 Different Life Tables Reflect Different
Approaches to Defining Cohorts and Age
Structure.
Dynamic Life Table – Following the fate (cohort) of a
group of individuals born at a given time (year).
Time-specific Life Table – One sample period
assumes: constant birth and death rates
each cohort sample according to actual population
proportions.
Chapter #10 – Population Growth
(pg. 204 – 221)
10.4 Life Tables Provide Data for Mortality and
Survivorship Curves.
Gray Squirrel
(Sciurus carolinensis)
Years
and
Months
Stonecrop
(Sedum smallii)
Chapter #10 – Population Growth
(pg. 204 – 221)
10.4 Life Tables Provide Data for Mortality and
Survivorship Curves.
Chapter #10 – Population Growth
(pg. 204 – 221)
10.4 Life Tables Provide Data for Mortality and
Survivorship Curves.
Type I – when individuals live out their
physiological life span
followed by heavy mortality
at the end (convex).
ex. - large mammals and
humans
Chapter #10 – Population Growth
(pg. 204 – 221)
10.4 Life Tables Provide Data for Mortality and
Survivorship Curves.
Type II – when survivorship rates do
not vary with age (straight
line).
ex. – adult birds (some
waterfowl and migratory
songbirds, small mammals
and reptiles.
Chapter #10 – Population Growth
(pg. 204 – 221)
10.4 Life Tables Provide Data for Mortality and
Survivorship Curves.
Type I – when mortality rates are
extremely high early in life
(concave).
ex. – fish, invertebrates,
plants (annual and perennial).
Chapter #10 – Population Growth
(pg. 204 – 221)
10.6 Birthrate and Survivorship Determine Net
Reproductive Rate (R0).
Fecundity – the potential reproductive capacity of an
organism or population.
Net Reproductive Rate (R0) – the average number of
females that will be left (progeny) during a lifetime
by a newborn female.
If (R0) is < 1.0, the population is decreasing.
If (R0) is = 1.0, the replacement.
If (R0) is > 1.0, the population is increasing.
Chapter #10 – Population Growth
(pg. 204 – 221)
10.7 Age-Specific Mortality and Birthrates Can Be
Used to Project Population Change.
Chapter #10 – Population Growth
(pg. 204 – 221)
10.7 Age-Specific Mortality and Birthrates Can Be
Used to Project Population Change.
From such a projection table (life table) you can calculate
the age distribution (stable or stationary) for each age
class or cohort in the population and to project
population growth (λ - lambda).
Chapter #10 – Population Growth
(pg. 204 – 221)
10.8 Stochastic Processes Can Influence
Population Dynamics.
Stochasticity –variation in a population from random
effects within a season or time period (t).
Demographic Stochasticity – variation in population growth/declining rates
from random effects among individuals in survival and reproduction
within a season or time period (t).
Environmental Stochasticity – variation in population growth/declining
rates from random effects arising from environmental factors or the
occurrence of natural disasters such as fire, flood, and drought
within a season or time period (t).
Chapter #10 – Population Growth
(pg. 204 – 221)
10.9 A Variety of Fators Can Lead to Population
Extinction.
1.
2.
3.
Resource Shortage
Restoration/Reintroduction
Potential new competitors,
predators, etc. (Human-assisted)
Chapter #10 – Population Growth
(pg. 204 – 221)
10.10 Small Populations are Susceptible to
Extinction.
1.
2.
3.
4.
5.
Stochastic Effects.
Wide Dispersal/Small Populations may have
trouble locating mates.
Allee Effect – a decline in reproduction or
survival at low densities.
Genetic Drift – random change in gene
frequency.
Inbreeding.