General Ecology, ECOL 3500, University of Georgia

Lecture: Populations, growth & regulation

Updated: 13 February, 2009


Reading assignments

  • Smith & Smith, Chapters 8-12.

Topics

  • Define population
    Location, species, race, age, ...

  • Focus on what limits population size
    • Resources
    • Density vs density independent factors
    • Abiotic vs biotic factors
    • Age structure
    • Sex ratio
    • Metapopulations, demes, subpopulations
    • Source versus sink populations

  • How to measure size
    • Number (N)
    • Biomass (dry weight)

  • Human populations
    • World population size now?
    • Predicted size?
    • Japan's population size now?
    • Predicted size in 2030?

  • Rates of change
    • Birth rate (+)
    • Death rate (-)
    • Immigration (in migration) (+)
    • Emigration (out migration) (-)

  • Exponential growth model (Smith & Smith, page 202)

    • dN/dt = (b - d) N

      where
      N = population size
      b = instantaneous per capita birth rate
      d = instantaneous per capita death rate

    • dN/dt = r N

      where
      r = instantaneous per capita growth rate = intrinsic rate of population growth = rmax

  • Logistic growth model (Smith & Smith, page 218)

    • dN/dt = r N [(K - N) / K]

      where
      K = "carrying capacity"
      above which N decreases
      below which N increases
      when N = K, N remains same

  • Life tables (Smith & Smith, pages 204-207)
    • R0 = Net reproductive rate
      = the average number of females that will be produced during a lifetime by a newborn female.
      • lx = probability at birth of surviving to any given age, x.
      • mx = age specific birth rate (= bx in Smith & Smith).

  • Hans Rosling: New insights on poverty and life around the world

  • Economy -- Dow

  • 2008 Latest Edition - Did You Know 3.0 - From Meeting in Rome this Year

  • Slides

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