1. Asexual reproduction involves a single parent and produces offspring that are genetically identical. It is common in unicellular organisms and allows for rapid population growth. 2. Sexual reproduction involves two parents and produces offspring with genetic variation. In humans, gametes from the male and female reproductive systems fuse during fertilization, forming a zygote that develops into an embryo. 3. Reproduction, whether asexual or sexual, ensures the continuity of species from one generation to the next. It increases genetic diversity which allows populations to adapt to their environments.

1. REPRODUCTION

2. Asexual Reproduction
• It is a mode of reproduction involving a single parent. Asexual
reproduction does not involve the fusion of gametes, and therefore, the
off-springs produced are genetically identical to the parent.
• The organisms produced by asexual reproduction are less diverse in
nature.
• This type of reproduction is practised widely by unicellular organisms.

3. Modes of Asexual reproduction
1. Fission
• Fission is defined as the splitting of the organisms into two halves and each half gives rise to a new organism. For example, Amoeba,
bacteria.
• The most common type of fission is binary fission. It is a division of organisms such as bacteria into two or more parts.
a) Binary Fission -> The most common type of fission is binary fission.
It is a division of organisms such as bacteria into two.

4. b) Multiple Fission
Plasmodium reproduces through multiple fission where one single cell divides its nucleus to
form many nuclei. This is followed by the division of the cell body to form daughter cells,
each having a single nuclei.

5. 2. Fragmentation
• Fragmentation is another mode of asexual reproduction in which
organism breaks into pieces and each piece give rise to a new
organism. For example, Spirogyra

6. 3. Regeneration
• Regeneration is the ability to form new organisms from body parts. Cut or broken part generates a new
organism. For example, Hydra, Planarians.
• Regenerative cells help to regenerate.

7. 4. Budding
• Budding is a type of asexual reproduction in which a small
cyst-like structure is formed on the parent’s body, which
gives rise to a new individual.
• Bud may remain attached to the parent (yeast) or may
separate and become a new individual (hydra).

8. 5. Spore formation
• Organisms such as fungi (Rhizopus)
make spores that can grow into
completely new individuals when
dispersed from their fruiting
bodies.
• Spores are produced inside
sporangia.
• They are covered by a thick outer
layer that protects them in adverse
conditions.
• When spores get suitable
environmental conditions, they
germinate and begin to grow.

9. 6. Vegetative propagation
• This is a type of asexual reproduction seen in plants.
• The vegetative parts of the plant, like leaves, stems, and roots,
give rise to a new plant.
• Vegetative propagation can be artificial or natural.
• Natural vegetative propagation happens through
Tuber (e.g. Potato)
leaves (e.g. bryophyllum),
stem (e.g. turmeric, ginger),
bulbs ( e.g. onion, lily), etc.
• Artificial methods include cutting (rose), grafting, layering and
plant tissue culture.

11. • Reproduction enables and ensures the continuity of species, generation after generation.
• Reproduction at its most basic level involves making copies of the blueprints of body design.
• The chromosomes in the nucleus of a cell contain information for the inheritance of features from
parents to the next generation in the form of DNA (Deoxyribo Nucleic Acid) molecules.
• The DNA in the cell nucleus is the information source for making proteins. If the information is
changed, different proteins will be made. Different proteins will eventually lead to altered body
designs.
• The cells use chemical reactions to build copies of their DNA. This creates two copies of the DNA in
a reproducing cell, and they will need to be separated from each other.
• To ensure that, a cell divides itself into two cells, each cell containing its own DNA and cellular
apparatus.
• Now, both these cells will be identical, but we cannot say that copying of the DNA will be 100%
identical.
• There might be some variations in the chemical reaction which means organisms cannot create
exact copies of themselves.
VARIATION

12. SEXUAL REPRODUCTION
Sexual reproduction involved two different parent organisms involving a female and a male parent.
• Significance of Sexual Reproduction
• Sexual reproduction is the source of variation. The mixing of two organisms gives rise to new
recombinants or variants. Sexual reproduction involves the mating of germ cells also known
as gametes. When male gametes and female gametes each with a haploid (half) set of
chromosomes combine they will form a diploid zygote. Zygotes undergo repeated divisions to form
a new organism.
• In humans, the male gamete is small and motile whereas the female gamete is large and non-
motile.

13. Sexual reproduction in flowering plants :-
a) Reproductive parts of a flower :-
• The stamen and pistil are the reproductive parts of the flower.
• Stamen is the male reproductive part. It produces pollen grains in
the anther which contains the male germ cell (male gamete).
• Pistil is the female reproductive part. It produces ovules in the
ovary which contain the female germ cell (female gamete).

14. b) Pollination :-
The transfer of pollen grains from the anther to the stigma
of a flower is called pollination.
It takes place by wind(Anemophily), water (Hydrophily) insects
(Zoophily), Birds (Ornithophily) or Bat
(Entomophily, Animals
(Chiropterophily).
It is of two types:-
(A) Self pollination: If the pollen grains are transferred from the
anther to the stigma of the same flower it is called self
pollination. E.g.- Pea, Wheat, Rice, Chinarose etc.
(B) CROSS POLLINATION:- it is the transfer of pollen grains from
the anther of one flower to the stigma of another flower born
on other plant of the same species.

15. c) Fertilisation :-
• After the pollen grain is transferred to
the stigma it produces a pollen tube
which passes through the style and
enters the ovary and ovule.
• In the ovule the male germ cell (male
gamete) fuses with the female germ
cell (female gamete) to form a zygote.
This process is called fertilisation.
After fertilisation the zygote divides
several times and forms the embryo which
then develops into the seed and the ovary
develops into the fruit.

16. Germination:
It is the initial stage in the growth of a seed to develop into a seedling under appropriate
conditions.

17. SEXUAL REPRODUCTION
• It is the process of producing new organisms from two parents by making use of
their sex cells or gametes. e.g- human, fish, dogs, cats and most of the flowering
plants.
•Thus the two major process i.e. formation of gametes and fusion of gametes
constitutes sexual reproduction.
•Two sexes namely Male( producing male gamete / Sperm) and Female (producing
female gamete / Ova) are involved.
Significance of sexual reproduction:
1. It promotes variation and thus promotes diversity of characters in the
offspring’s.
2. 2. It plays a prominent role in the origin of new species.

18. SEXUAL REPRODUCTION IN HUMAN BEINGS
• Sexual reproduction involving male reproductive organ and female reproductive
organ (growth to
•The reproductive organs of human being i.e. Testis in male and ovary in female
become functional only after attaining sexual maturity.
In male sexual maturity is attained at the age of 13-14 years while in female at the
age of 10-12 years. This is known as the age of puberty.
PUBERTY: It is the age at which the sex hormone or gametes begin to be produced
and the boy and girls becomes sexually mature.

19. SEXUAL MATURITY IN HUMAN BEING
• Various changes takes place in human body at the time of sexual maturity:-
• Changes common in both boys and girls:-
1) Thick hair growth in armpits & genital area between the thigh (also called Pubic
region).
2) 2) Thinner hair on legs, arms and faces.
3) 3) Oily skin and appearance of pimples

20. Human Reproductive System
• a) Male reproductive system :
• It consists of two portions one
that produces germ cell and the
other that deliver the germ cell
to the site of fertilisation.
• The human male reproductive
systems consists of the following
organs:-

21. • The male reproductive system comprises a pair of the testis, glands, accessory ducts, and male
genitalia.
• The testis is the site where male gametes or germ cells are produced. They are located outside
the abdominal cavity in a sac-like structure known as the scrotum. This is to maintain the lower
temperature required for the formation of sperm.
Testis produces the male hormone testosterone needed for the development of secondary sexual
characteristics in males such as the formation of beard and moustaches and also in the
development of sperm.
• Vas deferens is a duct that transports sperm to the urethra, which is a common passage for
urine and sperm ejaculation.
• Prostate glands and seminal vesicles are also found in males to nourish and for easy transport
sperm in the female genital tract. All these secretions along with sperm form the semen.

22. Female Reproductive System
• The female reproductive
system consists of a pair of
ovaries, uterus, cervix,
vagina, and external
genitalia.

23. • Female eggs or ova are produced in the ovaries. The formation of ova in the ovaries is known as
oogenesis.
• The ovary produces female hormones such as oestrogen, progesterone. These hormones are
needed for female sexual development and well as for pregnancy.
• The fallopian tube carries ova from the ovary to the womb. Two oviducts joined to form the uterus.
Uterus then opens into Vagina via the cervix.

24. • Sperm enter into the female vagina at the time of sexual
intercourse. Then the sperm reaches the fallopian tube where it
fuses the ova to form a zygote. This is known as fertilisation.
• Then the zygote divides to form an embryo. The embryo gets
implanted into the uterus. The embryo development occurs in the
uterus to form the foetus.
• Mother supplies nutrition to the growing foetus via the placenta.
• The placenta helps in the exchange of nutrients, gases and the
removal of excretory products.
• The development of a child inside the womb of the mother takes
place for about 9 months. Then the rhythmic uterine contraction
leads to the delivery of the baby outside the female body.

25. Menstruation
• If the egg is not fertilised, the uterine lining is shed off in the form of fluid known as menstrual fluid.
The discharge occurs from the vagina as blood and mucus. This is known as menstruation.
• It lasts for about 2 to 8 days.

26. REPRODUCTIVE HEALTH
• It is defined as the state of well being in terms of safe sex, reproductive fitness as well as the
absence of any reproductive diseases. Unsafe sex leads to different diseases which are known as
sexually transmitted diseases.
Some of the sexually transmitted diseases are as follows-
• Gonorrhoea is caused by bacteria
• Syphilis is caused by bacteria
• AIDS (acquired immunodeficiency syndrome) is caused by a virus HIV(human immunodeficiency
virus)

27. VARIOUS METHODS OF CONTRACEPTION
• CONTRACEPTIVE -:
• Contraceptives are devices that prevent unwanted pregnancy and
help avoid STDs.
• Contraceptives can be of various types such as mechanical
barriers, hormonal/chemical methods, surgical methods, etc.
• 1. Mechanical barriers
• Condoms are one of the most effective methods of contraception.
• A mechanical barrier that stops the semen from entering the
female tract preventing pregnancy.
• It also avoids the possibility of contracting STDs.
• Note -: Diaphragms are barriers that can be added inside the
female reproductive tracts.

28. 2. Chemical method
a) Contraceptive pills change the level of hormones in the body that
prevents the release of the ovum from the ovaries.
b) Emergency pills are those pills which can be taken after coitus to
avoid pregnancy.
They quickly change the level of hormones in the body and prevent a
successful implantation even if the egg gets fertilized.
3. IUD (Intrauterine Device)
• They can be used for a couple of years.
• It is a device that is inserted into the uterus, changing its shape
and preventing successful implantation of the zygote. E.g. loop or
Copper T.
4. Surgical method (Sterilization)
• Sterilization is a surgical method of going permanently sterile.
• This can be done in both males and females.
• In males, it is called vasectomy and in females, it is called