Mon. Tues. Wed. Thurs. Fri.

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Mon. Tues. Wed. Thurs.
Fri.
Week of Oct. 20
Week of Oct. 27
Independent project set-up
T lab switch?
Week of Nov. 3
Exam 2
Forest ecology lab dress for weather
Week of Nov. 10
Independent project analysis
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• What do we measure?
• Total population size number of indivduals
• How they are arranged in space
• How many are in each age or size class

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Figure 13.5
There is a simple statistical test to test for
distribution Mechanisms?
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• What do we measure?
• Total population size number of indivduals
• How they are arranged in space
• How many are in each age or size class

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Outline Introduction How are populations
defined and measured? How do populations
grow? How does population size change through
time and space?
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Growth births deaths immigration
emigration When calculating growth rate,
usually just seeing change in numbers over time
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Populations grow by multiplication rather than by
addition Just like interest in the bank
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Figure 14.3
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Exponential growth

• new individuals are added (born) to population
  continuously
• r per capita growth rate contribution of each
  individual in population

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Exponential growth
dN/dt rN
Rate at which individuals are added growth rate
on a per individual basis x population size
derivative of exponential equation slope of
line
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Figure 14.4
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Exponential vs. Geometric Growth Exponential
continuous reproduction - growth is smooth
curve Geometric discrete breeding seasons -
calculate growth at discrete intervals
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Geometric growth
Growth rate ? population size at one time
point/ size at previous time point N (t1)
? N(t) N(t) N(0) ?t
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Geometric growth N(t) N(0) ?t
Exponential growth N(t) N(0) ert

• er
• Ln ? r

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Figure 14.5
Per capita growth rate constant Rate of
increase dN/dt, increases with N
Exponential
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Figure 14.6
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Age structure ( of individuals in each age
class) of a population affects population
growth Why??
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Figure 14.8
Stable Fast growth
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Age structure of a population affects population
growth
Life table a summary by age of the survivorship
and fecundity of individuals in a
population Shows differences in birth and death
rate for different parts of population
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Table 14.3
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Figure 14.7
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Stable age distribution the proportion of
individuals in various age classes in a
population that has been growing at a constant
rate - only happens if age-specific birth and
death rates are constant over time - each age
class grows at same rate
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What parameters affect growth rate?
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More common to see this pattern Whats going on?
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Density dependence
Lots of examples in book Common in nature
Some factor that affects growth rate
Some metric of population size
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Figure 14.19
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Density independence
Very few examples in book Common in nature
Some factor that affects growth rate
Some metric of population size
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Figure 14.27
Population Size
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Logistic growth
R changes as N changes such that
r ro(1-N/K)
r intrinsic growth rate at small N x the
reduction in growth rate due to crowding K
carrying capacity of population
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Logistic growth
dN/dt roN (1-N/K)
Change in N with time intrinsic growth rate at
small N x population size x the reduction in
growth rate due to crowding
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Figure 14.17
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Figure 14.16
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If I give you an equation and a value for K
and/or r or ?, I expect that you can sketch the
graph. I expect that you will understand what
the terms in the equations mean. I expect that
you understand the assumptions of each model and
the differences between them. I expect that you
know what is in a life table and what parameters
affect growth rate and what a life table can be
used for.