Download REPRODUCTION IN ANIMALS

©
CBSEPracticalSkills.com
Edulabz International
REPRODUCTION IN
ANIMALS
9
TEXTBOOK QUESTIONS AND THEIR ANSWERS
Q.1. Have you seen the young ones of different animals? Try to
name some of the young ones by completing the table.
S. No
Animal
Young one
1.
Human
Baby
2.
Cat
3.
Dog
4.
Butterfly
5.
Hen
6.
Cow
7.
Frog
CBSEPracticalSkills.com
Chick
1
©
Edulabz International
©
CBSEPracticalSkills.com
Edulabz International
Ans.
S. No
Animal
Young one
1.
Human
Baby
2.
Cat
Kitten
3.
Dog
Puppy
4.
Butterfly
Caterpillars
5.
Hen
Chick
6.
Cow
Calf
7.
Frog
Tadpole
Q.2. Can you tell how chicks and caterpillars are born?
Ans. The chicks and caterpillars are born out of sexual reproduction
and hatched from the eggs, so they are oviparous animals.
Q.3. How are kittens and puppies born?
Ans. Kittens and puppies are also born out of sexual reproduction as
babies, so they are viviparous animals.
Q.4. What purpose does the tail in a sperm serve?
CBSEPracticalSkills.com
2
©
Edulabz International
©
CBSEPracticalSkills.com
Edulabz International
Ans. The tail helps sperm to swim in the oviduct and to reach the
egg for fertilization.
Q.5. Why do fish and frogs lay eggs in hundreds whereas a hen
lays only one egg at a time?
Ans. Though these animals lay hundreds of eggs and release
millions of sperms, all the eggs do not get fertilized and
develop into new individuals. This is because the eggs and
sperms get exposed to water movement, wind and rainfall.
Also, there are other animals in the pond which may feed on
eggs. Thus, production of large number of eggs and sperms is
necessary to ensure fertilization of at least a few of them.
Q.6. How could a single cell become such a big individual?
Ans. The fusion of single sperm cell with single egg cell, results in
the formation of fertilized egg or zygote. This zygote begins to
develop into an embryo. In this process zygote divides
repeatedly and form embryo. Thus, the embryo continues to
develop in the uterus of the mother. It gradually develops the
body parts and when the development of the fetus is
completed, the mother gives birth to the baby and that baby
becomes such a big individual.
CBSEPracticalSkills.com
3
©
Edulabz International
©
CBSEPracticalSkills.com
Edulabz International
Q.7. Can you give some example of viviparous and oviparous
animals?
Ans. Viviparous animals – The animals which give birth to young
ones are called viviparous animals.
Examples – Humen, Elephant, Horse, Cow, Buffalo, Donkey,
Monkey etc.
Oviparous animals – The animals which lay eggs are called
oviparous animals.
Examples – Duck, crow, pigeon, peacock, swan etc.
Q.8. Explain the importance of reproduction in organisms.
Ans. Reproduction is essential for the continuation of a species. It
ensures the continuation of similar kinds of individuals,
generation after generation.
If reproduction does not take place, no living being would
survive on earth.
Special characters of an organism are carried over to its next
generation through reproduction only.
Q.9. Describe the process of fertilization in human beings?
CBSEPracticalSkills.com
4
©
Edulabz International
©
CBSEPracticalSkills.com
Edulabz International
Ans. Human beings reproduce sexually. The fertilization takes place
inside female body. Males eject sperms inside female body, so,
millions of sperms are transferred into the female body. The
sperms swim in the oviduct with the help of their tails to reach
the egg. One of the sperms may fuse with the egg. Such fusion
of the egg and the sperm is called fertilization.
During this process the nucleus of the sperm fuses with the
nucleus of ovum forming a single nucleus. Thus zygote is
formed with a single nucleus, this completes the process of
fertilization.
Q.10. Choose the most appropriate answer :
(a) Internal fertilization occurs
(i) in side the female body.
(ii) outside the female body
(iii) in side the male body.
(iv) outside the male body.
(b) A tadpole develops into an adult frog by the process of
(i) fertilization
CBSEPracticalSkills.com
5
(ii) metamorphosis
©
Edulabz International
©
CBSEPracticalSkills.com
(iii) embedding
Edulabz International
(iv) budding
(c) The number of nuclei present in a zygote is
(i) none.
(b) one.
(iii) two.
(iv) four.
Ans. (a) (i) In female body
(b) (ii) metamorphosis
(c) (iii) two
Q.11. Indicate whether the following statements are True (T) or
False (F) :
(a) Oviparous animals give birth to young ones.
( )
(b) Each sperm is a single cell.
( )
(c) External fertilization takes place in frog.
( )
(d) A new human individual develops from a cell called
gamete.
( )
(e) Egg laid after fertilization is made up of a single cell.
( )
(f) Amoeba reproduces by budding.
( )
(g) Fertilization is necessary even in asexual reproduction.
( )
CBSEPracticalSkills.com
6
©
Edulabz International
©
CBSEPracticalSkills.com
Edulabz International
(h) Binary fission is a method of asexual reproduction.
()
(i) A zygote is formed as a result of fertilization.
( )
(j) An embryo is made up of a single cell.
( )
Ans. (a) False
(b)
True (c)
True (d) False
(e) True
(f)
False(g)
False (h)
(i) True
(j)
False
True
Q.12. Give two differences between a zygote and a fetus.
Ans.
Zygote
Foetus
1. Zygote is formed
by the fertilization
of sperms and
ovum.
2. Zygote does not
have well
developed limbs.
1. Foetus is formed by
the repeated division of
the zygote.
2. Foetus has well
developed and
identifiable limbs.
Q.13. Define asexual reproduction. Describe two methods of
asexual reproduction in animals.
Ans. The type of reproduction in which only a single parent is
involved is called asexual reproduction. It takes place by
different methods like budding and binary fission. Let us
discuss these two methods :
CBSEPracticalSkills.com
7
©
Edulabz International
©
CBSEPracticalSkills.com
Edulabz International
1. Budding – It takes place in Hydra and Bacteria. In this
type of reproduction, new individuals develop from the
buds of the old individual. Slowly it grows and develops
into separate individual.
2. Binary fission – It takes place in amoeba. In this type of
reproduction, a single organism divides into two. The
nucleus of the Amoeba divides into two followed by the
division of its body, each part getting one nucleus
develops into separate individual.
Q.14. In which female reproductive organ does the embryo get
embedded?
Ans. The embryo get embedded in the wall of the uterus of female
body for further development.
CBSEPracticalSkills.com
8
©
Edulabz International
©
CBSEPracticalSkills.com
Edulabz International
Q.15. What is metamorphosis? Give examples.
Ans. The transformation of the larva into an adult through
drastic changes is called metamorphosis.
The animals that undergo metamorphosis are –
(i) Silkworm :– egg → larva (caterpillar) → pupa → adult)
(ii) Frog :– egg → tadpole larva → adult) etc.
Q.16. Differentiate between internal fertilization and external
fertilization.
Ans.
Internal Fertilization
1. It takes place inside the
External Fertilization
It takes place outside the
female body.
female body.
2. Sperms are ejaculated
in female’s body by the
male.
In external fertilization the
sperms are discharged in
open.
3. This is observed in
human beings, hen,
This is observed in frogs,
cows, dogs, buffalow
fish, starfish etc.
etc.
CBSEPracticalSkills.com
9
©
Edulabz International
©
CBSEPracticalSkills.com
Edulabz International
Q.17. Complete the cross-word puzzle using the hints given
below
Across
1.
The process of the fusion of the gametes.
6.
The type of fertilization in hen.
7.
The term used for bulges observed on the sides of
the body of hydra.
8.
Eggs are produced here.
Down ward
2.
Sperms are produced in these male reproductive
organs.
3.
Another term for the fertilized egg.
4.
These animals lay eggs.
5.
A type of fission in amoeba.
CBSEPracticalSkills.com
10
©
Edulabz International
©
CBSEPracticalSkills.com
Edulabz International
Ans.
(1) Fertilization
(2) Testis
(3) Zygote
(4) Oviparous
(5) Binary
(6) Internal
(7) Buds
(8) Ovary
CBSEPracticalSkills.com
11
©
Edulabz International