1. Population
Demography and
Dynamics
Adan, Fatima Ellese
Jerusalem, Czar Alfeo
Solisa, Valerie

2. Demography
• From the word “Demo” and “graphy”
• It includes the study of how a
population changes over time.
Population Dynamics
• Population fluctuations from year to
year or place to place

3. Factors Affecting Population
Demography
• Fertility
• Mortality
• Immigration
• Emigration

4. Population Growth
• Population growth is affected
by:
–sex ratio
–Generation time

5. Sex Ratio
• In a study conducted by Joseph Elkinton,
J. H. Myers and G. Boettner
• egg masses of forest caterpillars from
low-density sites produced significantly
more females than those from high-
density sites, for which the numbers of
males and females were equal or slightly
in favor of males.

6. Sex Ratio
• The female bias of the sex ratio of
low-density populations increases
the potential rate of increase of the
population and may arise from local
mate competition when populations
are sparse.

7. Generation Time
• Short generation time results
in the increase in population
growth rate but can be
diminish more rapidly if birth
rates decrease suddenly.

8. Age Structure
• Cohort or group of individuals
w/in the same age.
• Population with large number of
young individual tends to grow
rapidly.

9. Age Structure Pyramid

10. Life Tables
• Contains
–fate of a cohort from birth until
death
–number of offspring produced
–individuals that died each year
– number of individuals that
survived

11. Life Table

12. Survival Curve
• a graphic method that shows some
of the data in life table
• It shows
– survivorship of a population
–percentage of the original
population that survive to a given
age.

15. • Standardized Survival
Schedule (lx)
• Age-Specific
Survivorship (gx)
Survival Curve

16. • Life Expectancy (ex)
Survival Curve

17. Pambasag!
1. What is
demography?

18. Pambasag!
2. What are the four
factors affecting
population
demography?

19. Pambasag!
3. The shorter the
______ the higher
the population
growth rate.

20. Pambasag!
4. It is a type of a life table which
is commonly used for organisms
that are difficult to classify by age
and the ecological role defend
more on their size or stage of
development.

21. Pambasag!
5. It is a curve used to
demonstrate the
survivorship of the
organisms in a certain
population.

22. Pambasag!
6. A population with a
large number of young
individuals tends
_______ in growth
rate.

23. Pambasag!
7. What is the most
commonly effect to a
population with a large
ratio of female
individuals?

24. Pambasag!
8. Age structure
is defined by
________ in
each cohort.

25. Pambasag!
9. The sudden change in
demography and structure
of a population.

26. Pambasag!
10. What is the possible effect
of the increase in generation
time together with the increase
in number of males in a
population?

27. Pambasag!
11-20. Show your solutions.
Age (year/s) Number of living individuals
0 300
1 267
2 222
3 197
4 156
5 130
6 95
7 50
8 25

28. References
• Campbell,Neil. Reece