This is a presentation about population ecology

1. Population ecology
- PRESENTED BY A.A.F., MSC.

2. Population
Ecology
• Population ecology deals with the study of the
structure and subtleties of a population
comprising a group of interacting organisms of
the same species that occupy a given area.
• The demographic structure of a population is a
key factor that is characterized by the number of
individual members (population size) present at
each developmental stage of their cycle to
identify whether the population of a specific
species is growing, shrinking, or remaining
constant in terms of its size.

3. Population Density
• Densely packed population of individuals.
The gene pool
(total cumulative genes in a population at a certain time)
• The gene pool (total cumulative genes in a population at a certain time) of
an organism is affected as those phenotypes that are compatible with the
environment are selected by nature and are inherited by the next progeny

4. Population Growth Models

5. Population
Growth Models
Populations change over time and space
as individuals are born or immigrate
(arrive from outside the population) into
an area and others die or emigrate
(depart from the population to another
location).
Populations grow and shrink and the age
and gender composition also change
through time and in response to
changing environmental conditions.

6. Population Growth Models
• Exponential growth
- The accelerating pattern
of increasing population
size.

7. Population Growth Models
• G = r x N (also expressed as dN/dt = r x N).
• G (or ) is the population growth rate, it is a
measure of the number of individuals added
per time interval time.
• r is the per capita rate of increase.
• r = (birth rate + immigration rate) - (death rate and
emigration rate).
• N is the population size, the number of
individuals in the population at a particular
time.

8. Population Growth Models
• Logistic Growth
• When resources are limited,
populations exhibit logistic
growth.

9. Population Growth Models
• Where K is the carrying capacity - the maximum
population size that a particular environment can sustain
("carry"). Notice that this model is similar to the
exponential growth model except for the addition of the
carrying capacity.
• In the exponential growth model, the population growth
rate was mainly dependent on N so that each new
individual added to the population contributed equally to
its growth as those individuals previously in the
population because per capita rate of increase is fixed. In
the logistic growth model, individuals' contribution to
population growth rate depends on the amount of
resources available (K). As the number of individuals
(N) in a population increases, fewer resources are
available to each

10. Factors limiting population growth
•Limited food
•Water
•Living space
•Natural disasters
• Predation
• Rapid spread of disease

11. Factors limiting population growth
• Density-dependent factors (biological in nature/biotic)
• inter- and intraspecific competition for food and mates,
accumulation of waste, and disease
• Density-independent factors
• NOT depend on population size; these factors are
independent of, or not influenced by, population density.

12. Reading materials:
https://bpb-us-w2.wpmucdn.com/u.osu.edu/dist/0/5437/files/2021/07/Population-Ecology-6.pdf
https://cmpcollege.ac.in/wp-content/uploads/2020/04/Unit-I-Population-Ecology.pdf
https://oer.galileo.usg.edu/biology-textbooks/4/
- chapter 2 population ecology