Population Dynamics
(Chapter 10)
1950
1
Estimating Patterns of Survival
•
Three main methods of estimation:
 Cohort life table
 Identify individuals born at same time
and keep records from birth.
 Static life table
 Record age at death of individuals.
 Age distribution
 Calculate difference in proportion of
individuals in each age class.
 Assumes differences from mortality.
2
Survivorship Curves
•
•
•
Type I: Majority of mortality occurs among
older individuals.
 Dall Sheep
Type II: Constant rate of survival throughout
lifetime.
 American Robins
Type III: High mortality among young,
followed by high survivorship.
 Sea Turtles
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4
5
6
7
Age Distribution
•
Age distribution of a population reflects its history
of survival, reproduction, and growth potential.
8
Age Distribution
•
Rio Grande Cottonwood populations (Populus
deltoides wislizenii) are ….
9
Dynamic Population in a Variable Climate
•
•
Grant and Grant studied Galapagos Finches.
Responsiveness of population age structure to
environmental variation.
10
Blacknose dace (Rhinichthys atratulus)
South Branch Codorus Creek
D-NFSTP
U-NFSTP
Blacknose Dace
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25
12
8
15
6
10
4
5
2
7711
668
9
7
65
6
65
62
M 7
or 3
e
Standard
length
Standard
length
(mm)
63
6
591
5569
553
7
50
55
53
51
47
4
449
4417
3485
35
43
1
32
4
39
3
297
2365
00
2333
Frequency
Frequency
10
20
11
700 Million Years of Eating DNA:
A Conserved Competence Regulon in Gamma-Proteobacteria.
Dr. Andrew Cameron
Microbiology Department
University of British Columbia, Vancouver, B.C.
Tuesday, March 6th, at 4:30 – 5:30 p.m.
Ruhl Student Center, Community Room
12
Rates of Population Change
•
•
•
Birth Rate: Number of young born per
female; seeds per individual plant.
Fecundity Schedule: Tabulation of birth rates
for females of different ages.
“Life Table” of survivorship per age grouping
(see above) combined with fecundity
schedule can be used to calculate net
reproductive rates.
13
Estimating Rates for an Annual Plant
•
Phlox drummondii (phlox)
 Ro = Net reproductive rate; Average number
of seeds produced by an individual in a
population over lifetime (“birth rate”).
 Ro=∑ lxmx
 X= Age interval in days.
 lx = % pop. surviving to each age (x).
 mx= Average number seeds produced by
each individual in each age category.
14
15
Estimating Rates for an Annual Plant
•
Because P. drummondii has non-overlapping
generations, we can estimate growth rate.
 Geometric Rate of Increase (λ):
 λ=N t+1 / Nt
 N t+1 = Size of population at future time.
 Nt = Size of population at some earlier
time.
16
Estimating Rates when Generations Overlap
•
Common Mud Turtle (K. subrubrum)
 About half turtles nest each year.
 Average generation time:
T = ∑ xlxmx / Ro
 X= Age in years
 Per Capita Rate of Increase:
r = ln Ro / T
 ln = Base natural logarithms
fwie.fw.vt.edu/VHS/Kinosternon_subrubrum.htm
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10_02.jpg
18
Dispersal
•
Africanized Honeybees
 Honeybees (Apis melifera) evolved in
Africa and Europe and have since
differentiated into many locally adapted
subspecies.
 Africanized honeybees disperse much
faster than European honeybees.
 Within 30 years they occupied most
of South America, Mexico, and all of
Central America.
19
Africanized Honeybees
20
Collared Doves
•
Collared Doves, Streptopelia decaocto,
spread from Turkey into Europe after 1900.
 Dispersal began suddenly.
 Not influenced by humans.
 Took place in small jumps.
 45 km/yr
21
Collared Doves
22
Rapid Changes in Response to Climate Change
•
Tree species began to spread northward
about 16,000 years ago following retreat of
glaciers and warming climate.
 Evidence found in preserved pollen in lake
sediments.
 Movement rate 100 - 400 m/yr.
23
Rapid Changes in Response to Climate Change
24
Dispersal in Response to Changing Food Supply
•
Holling observed
numerical
responses to
increased prey
availability.
 Increased
prey density
led to
increased
density of
predators.
 Birds moved.
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