Heredity refers to the passing of traits from parents to offspring. Variation means individuals have slight differences even if they belong to the same species. Genetics is the science of heredity and variation. During reproduction and cell division, small inaccuracies in DNA copying can lead to minor variations between individuals. However, not all variations provide equal chances of adaptation, as some variations may provide individuals with advantages depending on the environment. Mendel's experiments with pea plants showed that traits can be dominant or recessive, and are inherited independently. DNA contains the genetic information passed down from parents. In humans, sex is determined by X and Y chromosomes. Fossils provide evidence for evolution by showing extinct organisms and transitional forms between

2. HEREDITY AND EVOLUTION
Heredity- It means continuity of
features from one generation to
another.
Variation – means that
similarities among all the
individuals belonging to have
slight difference
Genetics- It is called
science of heredity and
variation.

3. • ACCUMULATION OF VARIATION
DURING REPRODUCTION
As we know that the organism have
both a common basic body design and
subtle (little ) changes in it
How it happens ?
One bacterium which have asexual reproduction.
If one bacterium divides and then the resultant two
bacteria divide again.
The four individual bacteria generated be very similar .
There would be only very minor differences between
them generated due to small in accuracies in DNA copying

4. After all different types of variation in
species have equal chances of
adaptation?
Not , depending on the nature of
variation in species ,different
individuals would have different
kinds of advantages.

5. • Heredity:- the rules of heredity determine the
process by which traits and characteristics are
pass one generation (inherited)
• Traits- a quality that makes one person or
thing different from another.
• Progeny – a thing or person who comes from
a particular parent or family.

6. Inherited traits
• As any body knows that inheritance is a factor
is a factor of a father and mother contribution
of DNA.
• So, there is a version in each child like some
similar to his mother and other are similar to
his father.

7. Mendel’s experiment

8. How do Mendel’s experiments show
that traits may be dominant or
recessive ?
• When Mendel first crossed pure tall plants ,
he found that only tall plants produce in the
first generation (F1).
• No dwarf pea plants were obtained in the
first –generation of progeny.
• When f1 tall plants were self pollinated,
mendel got tall and dwarf plants in F2
generation in 3:1.

9. • F2 generation ¾ plants were tall and ¼ were
dwarf .mendel called this charcter as
dominant trait and dwarf character as
dominant trait and dwarf as recessive trait.
• These may depend on identical or different ,
depending on the percentage .

10. Ratio
9:3:3:1

11. How do mendel’s experiment show
that traits are inherited
independently?

12. DEOXYRIBONUCLEIC ACID(DNA )

13. • We get information about heredity by DNA.
• Cellular DNA is the information source for
making proteins in the cell.
• A section of DNA that provides information for
One protein is called the gene for that protein.
• Single long thread of DNA but as separate
independent pieces each called a
chromosome

14. Sex determination

15. • In human chromosome have a maternal and paternal copy .
• such pair we have 22 pairs of chromosome called an
AUTOSOME but one pair called the sex chromosomes .
• women have a perfect pair of sex chromosomes pair
of sex chromosomes, both called( XX).
• Men have mismatch pair in which one is a normal
sized x and other short one( Y).
• A child who inherits an (X) chromosome from father
will be a girl.
• One who inherits a y chromosome from father will
be a boy (xy)

16. Eduzone classes

18. • Natural selection – it is the phenomenon
wherein nature selects organism having favorable
to environment.
• Genetic drift – the elimination of the genes of
certain traits from the small population when a
section of the species population dies of natural
calamity or migrates to other region is called
genetic drift .
• Thus the natural selection and genetic drift works
towards evolution but decrease in body weight
due to starvation is an acquired trait in the
beetles during their life time it will not bring any
change in the DNA.

19. Genetic drift Natural selection
It is a sudden and
quick process
It is a gradual and
slow process
It selects harmful
variations by
change
It selects only
adaptatively
useful variations

20. • Speciation-
Define-origin of new species from the
existing
One due to reproductive isolation of a
part of its
Population is called speciation

21. Thus the key factor in
speciation:-
1.Genetic variations
2.Geographical isolation
3.Natural selection
4.Genetic drift
5.Reproductive isolation

22. FOSSILS
FOSSIL

24. FOSSILS- they preserved remains or
impressions of the dead animals and
plants of the dead animals and plants
that lived in past
STUDY OF FOSSILS is known as paleontology
Palaeos =old, antos =beings, logos= science
If a dead insect gets caught in hot mud,
for example, it will
not decompose quickly, and the mud
will eventually harden and retain
the impression of the body parts of the
insect. All such preserved traces

25. Importance of fossils
• They provide evidence of equation of
evolution.
• They tells us about the extinct organisms eg.-
dinosaurs
• Also about link between two group
• Fossils are helpful to know about habit and
habitants of the extinct or living organisms.

26. • There are many types of evidence that
support the Theory of Evolution. These
pieces of evidence range from the minute
molecular level of DNA similarities all the
way up through similarities within the
anatomical structure of organisms.
When Charles Darwin first proposed his
idea of natural selection, he used mostly
evidence based on anatomical featuresof
organisms he studied.
• Two different ways these similarities in
anatomical structures can be classified is as
either analogous structures or homologous
structures.

29. • Homology
• The other classification of similar
anatomical structures is called
homology.
• In homology, the homologous
structures did in fact evolve from a
recent common ancestor.
• Organisms with homologous structures
are more closely related to each other.

30. • Analogy
• Analogy, or analogous structures, is
actually the one that does not indicate
there is a recent common ancestor
between two organisms.
• Even though the anatomical structures
being studied look similar and maybe
even perform the same functions, they
are actually a product of convergent
evolution .
• Just because they look and act alike
does not mean they are related closely
on the tree of life.

31. Evolution by stages
Evolution of complex organism
has taken place through a series
of DNA changes (mutations)
created bit by bit over
generations
For example -evolution of eyes

34. Artificial selection
•This is the usage of plant with desirable
characteristics to produce new varieties .
•Broccoli, cauliflower, cabbage, kohlarbi, and
kale are produce from its ancestor wild
cabbage by artificial selection
•Eg:- cabbage -by selecting short distance between the
leaves
•Cauliflower-by selecting sterile flowers
•Kale- by selecting large leaves
•Kholrabi- by selecting the swollen stem
•Broccoli- by arresting flower growth