Demographic Concepts


This article has sections titled

1 Introduction
2 Historical Development
3 Life Tables
4 Population Growth
4.1 Net reproductive rate per generation
5 The Euler–Lotka Equation
6 The Reproductive Value Function

Keywords: birth rate; death rate; survival; mortality; reproduction; population growth; life table; life history; life‐history evolution; stable age distribution; reproductive value

Figure 1.

Survival of 605528 female medflies reared in a total of 167 cages at the Moscamed Mass Rearing Facility in Tapachula, Chiapas, Mexico; the project was titled ‘Oldest‐Old Mortality in the Mediterranean Fruitfly’ and funded by the National Institute on Aging; data from JR Carey, Liedo D, Orozco and JW Vaupel and published as Appendix 3 in Carey (1993)

Figure 2.

Survival curve determined from 1289 skeletal remains at a human burial site (the Libben site) in the Great Black Swamp of northern Ohio, data shown in Table .

Figure 3.

General survival showing possible shapes: (a) linear scale; (b): logarithmic scale; Type I survival is good for most of the life and then there is a catastrophic decline; Type II survival rate is constant, which means the probability does not change with age; Type III survival is poor for youngest ages but then survival is high for the remainder of life.

Figure 4.

Visual presentation of population projection using px and mx values given in Table and starting with 100 age1 individuals; over a period of 1 year, age1 individuals move to age2 but survival is 0.4 yr−1 and so just 40 individuals are in age2; age2 individuals reproduce each with 11 female offspring and so there are 440 in age0 so the total population is 440 plus 40 or 480.

Figure 5.

Population growth in numbers showing early fluctuation followed by a smooth rise with a constant rate.

Figure 6.

(a) Fluctuation in population growth rate before settling on a constant value; (b) fluctuations in the fractions of individuals in each age class starting with 100% in age1; following fluctuations, the fractions become fixed and these fixed fractions are the stable‐age distribution.


Further Reading

Carey JR (1993) Applied Demography for Biologists with Special Emphasis on Insects. New York: Oxford University Press.

Caswell H (2001) Matrix population models. Construction, Analysis, and Interpretation, 2nd edn. Sunderland, MA: Sinauer Associates.

Ebert TA (1999) Plant and Animal Populations. Methods in Demography. San Diego, CA: Academic Press.

Graunt J (1662) Natural and political observations mentioned in a following index, and made upon the bills of mortality. Printed by Tho. Roycroft for John Martin, James Allestry, and Tho. Dicas, at the Sign of the Bell in St. Paul's Church‐yard. (Reprinted 1964. Journal of the Institute of Actuaries 90: 1–61.) This is a fascinating document in part because of the lists of reasons for death that cause a reader to run for the OED to find explanations.

Kingsland SE (1985) Modeling Nature. Chicago, IL: The University of Chicago Press.

Lovejoy CO, Meindl RS, Pryzbeck TR et al. (1977) Paleodemography of the Libben site, Ottawa County, Ohio. Science 198: 291–293.

Silvertown JW and Lovett‐Doust J (1993) Introduction of Plant Population Biology, 3rd edn. Oxford, England: Blackwell.

Stearns SC (1992) The Evolution of Life Histories, New York, NY: Oxford University Press.

Contact Editor close
Submit a note to the editor about this article by filling in the form below.

* Required Field

How to Cite close
Ebert, Thomas A(Jan 2006) Demographic Concepts. In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1038/npg.els.0003166]