This is best presentation related to science . major zoology. this topic is from chapter evolution from the zoology subject.i tried to make it easier for understanding of others. it is easy to understand the concept with examples.so try to understand.....easy easy easy.

5. All of the people inhabiting a specified area.
OR
A group of individuals or items that share one or
more characteristics living in the same area.

6. EXAMPLE
A colony of ants
A crowd of people

7. Population of ants

8. The world’s population is expected to reach seven billion
at the turn of 2011-12

9. The term:
Population size
The Actual counting of a total
population, the census method, is
not often possible in large animal
populations.
Census
method
collection of data
from the whole
population
rather than just a
sample.
The population
size is
expressed as
the population
present at a
particular
instant.

10. Population is of
two types
1. Absolute
population size (N)
2. Effective
population size (Ne)

11. The actual abundance of a
population or species.
Absolute
population
size
Absolute population

12. The effective
population size
(Ne)
The number of breeding individuals in an
idealized population that would show the
same amount of dispersion of allele
frequencies under random genetic drift.
Ne

13. There are four
Factors affecting
the population size

14. 1. BIRTH RATE
2. DEATH RATE
3. IMMIGRATION
4. EMIGRATION

15. BIRTH RATE
-the number of
live births per
1000 in a year.
Birth rates are affected by such
factors as nutrition ,fertility,
government policies and social
value.

16. DEATH RATE
-the number of
deaths per 1000
in a year.
Death rates are affected by disease,
war, medical technology, improved
health care, transportation
development and nutrition

17. -The number of people
moving into a country
IMMIGRATION
EMIGRATION

19. Determining
population size
Four steps
1. Direct observation 2. Indirect observation
3. Sampling 4. Mark- and –recapture

20. Counting each individual organism .It is useful if there are
few organisms in the study area , or they don’t move or they
are large. NOT useful if the study area is very large, many
organisms, organisms are small or move around a lot.
1

21. observe tracks ,nests or other signs that the organism
have been there . Useful if organisms move around a
lot, are small and or hard to find or if study area is
large.

22. Useful if popoulation is very large, or covers a large
area or is hard to remember which have been counted.
count the number of individuals in small area ,then
multiply to find the number in the larger study area

23. Animals are captured and marked and released into
the environment.

24. Genetic drift
Genetic drift is the random change in the
genetic composition of a population due
to chance events causing unequal
participation of individuals in producing
succeeding generations

25. BB individuals have big beaks , Bb individuals
have medium-sized beak and bb individuals have
small beaks. These birds live in a place where large
and small seeds are abundant, but no medium-
sized seeds are available . Populations of all big-
beaked individuals have a very high average fitness
they can crack open big seeds.
Populations of all small-beaked individuals do
well— but not quite as well as the big-beaked
individual. Medium-beaked individuals have the
lowest fitness .and no medium sized beaks
available.

26. A graph of these gene frequencies and the
population's resulting fitness levels is
shown. This sort of graph is called an
adaptive landscape
A graph of these gene frequencies and the
population's resulting fitness levels is
shown. This sort of graph is called an
adaptive landscape.

27. Genetic drift

28. Founder effect
Bottlenecks effect

29. Founder effects
A founder effect occurs when
a new colony is started by a
few members of the original
population

32. Bottlenecks Effect
Population bottlenecks occur
when large numbers of a
population are removed by
disease, overhunting, overfishing
or natural disasters.

34. Bottlenecks
Effect