REPRODUCTION IN ANIMALS CLASS 8 SCIENCE

3. There are two types of reproduction-

4. Sexual Reproduction: The
reproduction in which the both male
reproductive organs and female
reproductive organs involved to give
birth to new individual is called
sexual reproduction.

5. The male reproductive
organs include a pair
of testes, two sperms
ducts and a penis. The
testes produce male
gametes called
sperms. Millions of
sperms are produced
by the testes.

6. The female reproductive
organs are of ovaries,
oviducts[fallopian tubes] and
the uterus. The ovary
produces female gametes
called ova[eggs]. A single
matured egg is released into
oviduct by on of the ovaries
every month. Uterus is the
development of the baby
takes place. Like the sperm,
an egg is also a single cell.

7. An ovum (plural ova, ovum
meaning egg or egg cell) is a
haploid female reproductive
cell or gamete. Both animals
and embryophytes have ova.
The term ovule is used for the
young ovum of an animal, as
well as the plant structure that
carries the female
gametophyte and egg cell and
develops into a seed after
fertilization.

8. The first step in process of reproduction is the
fusion of as perm and an ovum. When sperms
come in contact with an egg, one of the
sperms may fuse the egg. Such fusion of the
egg and the sperm is called Fertilization

9. Fertilization involves the fusion of the male and the female
gamete. The male and the female gametes are released from the
male and the female reproductive organs. Sperms or male
gametes are released from the male reproductive organ i.e., the
penis. These sperms then enter the female body through the
vagina. Then, they travel through the fallopian tubes where they
meet the eggs. Hence, the process of fertilization takes place in
the fallopian tubes. During fertilization, the haploid nucleus of the
sperm and that of the ovum fuse with each other to form the
zygote. This zygote divides to form an embryo which in turn
develops into a foetus.
PROCESS OF FERTILISATION IN HUMAN
BEINGS

12. Internal Fertilisation- Fertilization which takes pace in side the
female body is called Internal fertilization
EX.-Human Beings,dog,cow etc.
External fertilisation- Fertilisation in which the fusion of male
and female gamete takes outside the body is called External
fertilisation. Example: frog, fish, starfish etc.

14. Fertilisation results in the formation of zygote which begins to
develop into embryo. The zygote divides repeatedly to give rise
to a balls of cells. The cells then begin to form groups that
develop into different tissues and organs of body. This
developing structure is termed an embryo. The embryo gets
embedded in the walls of uterus for development.

16. The stage
embryo in
which all body
parts can
been seen is
called Foetus.

17. Oviparous Animals- Animals which lay eggs outside their
bodies are known as oviparous animals. All birds, frogs,
lizards, crocodiles etc. belong to this group.
Viviparous Animals- Animals which give birth to young
ones are known as viviparous animals. Animals like lions,
tigers, dogs, and humans belong to this group.

18. Metamorphosis- The transformation of larva into
adult by drastic changes is called metamorphosis.

19. Asexual reproduction- It is a mode
of reproduction that does not
involve the fusion of the male and
the female gamete. It requires only
one parent, and the offspring's
produced are exact copies of their
parents.

24. Budding involves the formation of a new individual from the bulges,
known as buds formed on the parent body. This method of reproduction
is common in Hydra. In Hydra, the cells divide rapidly at a specific site
and develop as an outgrowth, called the bud. These buds, while being
attached to the parent plant, develop into smaller individuals. When
these individuals become mature enough, they detach from the parent’s
body and become independent individuals