LECTURE 08 POPULATION GROWTH AND REGULATION 2
read: 227-235
For this lecture, bring PRINTOUT of this and last Tuesday’s lecture outline
and bring PG. 73 FROM MANUAL
MAJOR CONCEPTS
1. The age structure of a population reflects its history of survival, reproduction, and
potential for future growth.
2. How fast a population grows depends on its age structure.
3. A life table summarizes age-specific schedules of survival and fecundity.
4. A life table can be used to estimate net reproductive rate (Ro), geometric rate of
increase (), generation time (T), and per capita rate of increase (r).
5. A survivorship curve summarizes the pattern of survival over time in a population.
Age structure: proportion of individuals in each age class.
Influences population growth rate.
Stable and growing population shave very different shapes 11.6
Shape of age structure shifts when populations change birth/death rates 11.7
Life Table analysis for differential equations
Includes complexity of age-specific survival and fecundity Table 11.1, Table 11.4
Summarizes demographic information by age class
Fecundity
Probability of survival
Life table: provides calculations of: Table 11.7
T = mean generation time
Ro = net reproductive rate (per lifetime); when Ro = 1, population is stable
r = ln Ro/T
 = er
Doubling time
t2 = ln2 / ln 
t2 = ln2 / r
ex = life expectancy
Cohort vs. static life tables (advantages and disadvantages) 11.8, 11.9, Table 11.6
Cohort: all individuals born at same time
Shapes of survivorship curves (Type I, II, and III) 11.10
Use life table to project future population size and age structure Table 11.2, Table 11.3
Get stable age distribution (SAD) with time, even with population growing
Each age class grows (or declines) at same rate ()
 fluctuates, then becomes constant with time
Assumes birth and death rates are constant