The document discusses human population ecology. It begins by describing the mark-recapture method used to estimate population size. It then discusses trends in human population growth, noting that while global population continues to increase, the rate of growth has slowed. Regionally, population growth is concentrated in developing countries. Two examples given are the demographic transitions seen in Sweden as a developed country versus continuing growth in Mexico as a developing country. Projections of future population size and its age/gender structure in South Africa are provided. The document concludes by questioning the earth's carrying capacity to support humans into the future.

1. UNIT 3:
POPOULATION
ECOLOGY

2. MARK-RECAPTURE METHOD
(PETERSON METHOD)
 N = estimated population size
 M = the number of individuals marked in the
first sample
 C = total number of individuals captured in 2nd
sample
 R = number of individuals in 2nd sample that are
marked
N = CM
R

3. 7. HUMAN POPULATION
 The human population is no longer growing
exponentially but is still increasing rapidly.
 No population can grow indefinitely, and
humans are no exception.
 The human population increased relatively
slowly until about 1650 and then began to grow
exponentially.

4. HUMAN POPULATION
 Though the global population is still growing, the
rate of growth began to slow during the 1960s

5. REGIONAL PATTERNS OF
POPULATION CHANGE
• To maintain population stability, a regional
human population can exist in one of two
configurations:
• Zero population growth =
High birth rate – High death rate
• Zero population growth =
Low birth rate – Low death rate
• The demographic transition is the move from
the first state toward the second state

6. REGIONAL PATTERNS OF
POPULATION CHANGE
• The demographic transition is associated with an
increase in the quality of health care and
improved access to education, especially for
women
• Most of the current global population growth is
concentrated in developing countries.

7. SWEDEN – DEVELOPED COUNTRY
MEXICO – DEVELOPING COUNTRY

8. POPULATION GROWTH IN SOUTH
AFRICA

9. PROJECTIONS OF S.A.POPULATION
SIZE

10. POPULATION GROWTH IN SOUTH
AFRICA
• The Population; total in South Africa was
last reported at 49991300 in 2010.
• The Population; total in South Africa was
49320150 in 2009.
• The Population; total in South Africa was
reported at 48793022 in 2008.

11. AGE AND GENDER STRUCTURES
• One important demographic factor in present
and future growth trends is a country’s age
and GENDER structure
• Age structure is the relative number of
individuals at each age.
• Age structure diagrams can predict a
population’s growth trends
• They can illuminate social conditions and help
us plan for the future.

12. AGE AND GENDER STRUCTURES

13. AGE DISTRIBUTION IN S. AFRICA

14. GENDER DISTRIBUTION IN S.A.

15. How many humans can the
biosphere support?
What is the earth’s carrying
capacity?
Our carrying capacity could
potentially be limited by food,
space, non-renewable resources,
or build-up of wastes