DAV Class 8 Science Chapter 14 Question Answer – Reproduction in Animals

The DAV Class 8 Science Book Solutions and DAV Class 8 Science Chapter 14 Question Answer – Reproduction in Animals are essential study tools for DAV public school students in Class 8.

DAV Class 8 Science Ch 14 Question Answer – Reproduction in Animals

DAV Class 8 Science Ch 14 Solutions – Reproduction in Animals

Something To Know

A. Fill In The Blanks:

Question 1.
Genetically identical individuals are produced by ________ reproduction.
Answer:
asexual

Question 2.
________ are the specialised cells that take part in sexual reproduction.
Answer:
Gametes

Question 3.
An animal, that produces both male and female gametes, is known as a ________ animal.
Answer:
hermaphrodite

Question 4.
A fertilised egg is also known as the ________ .
Answer:
zygote

Question 5.
The incubation period for a hen’s egg is ________ .
Answer:
21 days

B. Match the following:

Column I	Column II
(1) Hydra	(a) Hermaphrodite
(2) Reptiles	(b) Cal cite
(3) Earthworm	(c) Budding
(4) Gills	(d) Oviparous
(5) Egg shell	(e) Tadpole

Answer:

Column I	Column II
(1) Hydra	(c) Budding
(2) Reptiles	(d) Oviparous
(3) Earthworm	(a) Hermaphrodite
(4) Gills	(e) Tadpole
(5) Egg shell	(b) Calcite

C. Tick (✓) the correct option:

Question 1.
The site of fertilisation, in humans, is the-
(a) Uterus
(b) Oviduct
(c) Vagina
(d) Ovary
Answer:
(b) Oviduct

Question 2.
The reason, why parrot does not belong to the same group as that of monkey, man, cat, is that-
(a) It is not oviparous
(b) It undergoes internal fertilisation it is oviparous
(c) It undergoes external fertilisation.
(d) It is viviparous
Answer:
(a) It is not oviparous

Question 3.
An organism, which reproduces by Budding, is-
(a) Plasmodium
(b) Amoeba
(c) Yeast
(d) Spiro,gya
Answer:
(c) Yeast

Question 4.
A caterpillar develops into a silk moth through the process of-
(a) Fertilise tion
(b) Metamorphosis
(c) Hatching
(d) Parthenogenesis
Answer:
(b) Metamorphosis

Question 5.
A foetus can be best defined as-
(a) A fertilised egg
(b) A developing embryo
(c) A well developed embryo
(d) An unfrrtiliscd egg
Answer:
(c) A well developed embryo

D. Answer the following questions in brief:

Question 1.
Distinguish between asexual and sexual reproduction.
Answer:

Asexual Reproduction	Sexual Reproduction
A single parent is involved.	Two parents are involved.
Gametes are not formed.	Gametes are formed.
Is a fast process.	Is a slow process.
Offsprings are identical to parent.	Olisprings show some variations from parents.

Question 2.
How is reproduction carried out in Hydra?
Answer:
By Budding

Question 3.
How is fertilisation in a hen different from fertilisation in a frog?
Answer:
Internal fertilisation takes place in a hen, while external fertilisation takes place in a frog.

Question 4.
State the difference between oviparous and viviparous animals.
Answer:
Oviparous animals lay eggs, while viviparous animals give birth to young one.

Question 5.
Why is the number of eggs, laid by frogs at a time, much higher than those laid by a hen?
Answer:
A frog lays eggs in water, where eggs are exposed to predators and water current. But a hen lays eggs on land and takes care of them during incubation. Most of the eggs of a frog are destroyed by the time tadpoles come out of some of them. Hence, a frog needs to lay thousands of eggs. This is not the case with a hen.

Question 6.
How will you differentiate between a zygote and an embryo?
Answer:
A zygote is unicellular, while an embryo is multicellular.

Question 7.
It is the mother who gives birth to a child. How do children, then, get features of both the parents?
Answer:
A child gets genes from its father and mother. Hence, a child gets features from both the parents.

E. Answer the following questions:

Question 1.
Define the term ‘Metamorphosis’. List the changes that a tadpole undergoes to develop into a frog.
Answer:
A marked, and more or less abrupt developmental change in the structure and habit of an animal, occurring during its life cycle, is called metamorphosis. Metamorphosis in tadpole begins with the development of hind legs followed by front legs. Then the lungs develop. The tadpole then begins to swim to the surface of water to breathe. The intestine gets shortened to adapt to a carnivorous diet. The tail gets absorbed by the body during the last stages of metamorphosis.

Question 2.
Trace the sequence of events that lead to development of a chick from the fertilised egg of a hen.
Answer:
After fertilisation, the zygote starts dividing and moves down the oviduct. As it moves down, a number of protective layers get formed around it. The egg shell is one of these protective layers. The embryo develops inside the egg for around 21 days. Finally the egg shell breaks down and the chick comes out.

Question 3.
Where does fertilisation occur in human beings? How does the zygote formed eventually develop into an infant?
Answer:
Fertilisation occurs in oviduct in human female reproductive system. The zygote immediately divides into two cells. Then these cells divide again and again over the couple of days. This results in formation of a cluster of cells. This cluster of cells is called embryo. It moves down to the uterus and gets implanted in the lining of the uterus. It undergoes further rounds of cell divisions. Gradually, the embryo develops into the foetus. A foetus resembles a human being. After about 40 weeks of gestation, the fully developed child is ready to take birth.

Question 4.
Draw a neat well labelled diagram of the human sperm. Also, write how its shape and size help it in its functioning.
Answer:
The tail of sperm facilitates its swimming. A structure, at the tip of its head releases an enzyme which helps it penetrate the egg; in order to facilitate fertilisation.

The tail of sperm facilitates its swimming. A structure, at the tip of its head releases an enzyme which helps it penetrate the egg in order to facilitate fertilisation.

Question 5.
Draw a neat and well labelled diagram of
(i) the reproductive system of the human female
(ii) the male reproductive system.
Answer:

Question 6.
Write the functions of each of the following parts of the human female reproductive system:
(a) Ovaries
(b) Oviduct
(c) Uterus
Answer:
(a) Produces egg
(b) It is the site of fertilisation
(c) It is the site of implantation and further development of embryo

Value Based Question

Atul’s mother decides to get their garage cleaned. The maid comes running and informs that there is a pigeon nest in one corner having 3-4 eggs in it. She starts to look for the broom when Atul intervenes. He tells his maid that she should remove the nest only after 3 wrecks. His mother agrees to the suggestion and instructs the maid accordingly.

Question 1.
Why did Atul ask the maid to wait for 3 weeks?
Answer:
Atul knows that the eggs would take 3 weeks to produce chicks. Hence, he asked the maid to wait for 3 weeks.

Question 2.
What is the egg shell made up of?
Answer:
Calcite

Question 3.
State the values shown by Atul.
Answer:
Concern for animals

Something To Do

Question 1.
Visit a hospital and find out if there have been any twins, triplets or quadruplets that have been born there in the past years. Find out how these develop. What are the chances of their survival as compared to the normal single child?
Answer:
Do it yourself.

Question 2.
Although most mammals give birth to young ones, there are some that lay eggs. Find out more about such egg-laying mammals and share the information with your classmates.
Answer:
Platypus, Echidna

Question 3.
Prepare a list of five birds commonly found in your city. Find out about the types of nests they make and the time of the year one is most likely to find eggs in their nests. Also, find out the number of eggs laid at one time, the incubation period and the appearance of the eggs, for the live different birds listed by you.
Answer:
Do it yourself.

Question 4.
‘Dolly’ (Sheep) was the first cloned mammal. Find out where and how it was produced. Also, try to find out about the other animals that have been cloned.
Answer:
Do it yourself.

Question 5.
Complete the table given below:

Animal	What is the young one called?	Average Time taken for development of the young one	Average lifespan (years)
1. Lion
2. Cow
3.Horse
4. Elephant
5. Goat
6. Kangaroo
7. Cat
8. Dog
9. Whale

Answer:

Animal	What is the young one called?	Average Time taken for development of the young one	Average lifespan (years)
1. Lion	Cub	108 days	35
2. Cow	Calf	279 to 292 days	22
3.Horse	Foal	330-342 days	40
4. Elephant	Calf	617-645 days	70
5. Goat	Kid	145-155 days	15
6. Kangaroo	Joey	42 days	9
7. Cat	Kitten	64 days	25
8. Dog	Puppy	61 days	22
9. Whale	Calf	480-590 days	80-110 (Blue whale)

DAV Class 8 Science Chapter 14 Solutions – Reproduction in Animals Important Questions and Answers

I. Fill in the blanks:

1. Amoeba reproduces by ________ .
Answer:
Binary fission

2. Yeast reproduces by ________ .
Answer:
Budding

3. Hydra reproduces by ________ .
Answer:
Budding

4. Single parent is involved in ________ reproduction.
Answer:
Asexual

5. Two parents are involved in ________ reproduction.
Answer:
Sexual

6. Sperm is produced by ________ in the male reproductive system.
Answer:
Testis

7. Egg is produced by ________ in the female reproductive system.
Answer:
Ovary

II. Tick (✓) the correct answer:

Question 1.
How many types of gametes are formed during asexual reproduction?
(a) One
(b) Two
(c) Three
(d) Zero
Answer:
(d) Zero

Question 2.
How many types of gametes are formed during sexual reproduction?
(a) One
(b) Two
(c) Three
(d) Zero
Answer:
(b) Two

Question 3.
Which of these animals shows external fertlisation?
(a) Frog
(b) Crocodile
(c) Bird
(d) Mammal
Answer:
(a) Frog

Question 4.
Which of these is an oviparous animal?
(a) Chimpanzee
(b) Rat
(c) Human
(d) Eagle
Answer:
(d) Eagle

Question 5.
How many ovaries are present in the female reproductive system?
(a) One
(b) Two
(c) Four
(d) Eight
Answer:
(b) Two

Question 6.
Which organs works as a passage for semen?
(a) Testes
(b) Sperm ducts
(c) Penis
(d) Scrotum
Answer:
(c) Penis

III. Answer the following questions:

Question 1.
What do you understand by asexual reproduction?
Answer:
When a single parent is involved and no gamete formation takes place, the reproduction is called asexual reproduction.

Question 2.
What do you understand by sexual reproduction?
Answer:
In sexual reproduction, two parents are involved. Two types of gametes, Le male and female, is formed by the respective parents. The gametes fuse through a process; called fertilisation.

Question 3.
Explain binary fission.
Answer:
Binary Fission: This method is observed in unicellular organisms. During binary fission, the parent cell divides into two daughter cells. Examples: Bacteria and Amoeba.

Question 4.
What are gametes?
Answer:
The specialised cells formed by male and female parents which take part in sexual reproduction are called gametes. The male gamete is called sperm and female gamete is called ova; in multicellular animals.

Question 5.
Which are the different types of fertilisation seen in animals?
Answer:
Types of Fertilisation:
External Fertilisation: When fertilisation takes place outside the animal’s body, it is called external fertlisation. Example: Frogs, fishes.
Internal Fertilisation: When fertilisation takes place inside the animal’s body, it is called internal fertilisation. Examples: humans, crocodiles, birds, etc.

Question 6.
What do you understand by external development?
Answer:
When the embryo develops outside the animal’s body, it is called external development. External development is the norm in case of external fertilisation. In case of internal fertilisation, external development is seen in some animals; which lay eggs.

Question 7.
Explain the structure of a sperm.
Answer:
The sperm is composed of three parts, viz. a head, middle piece and a tail. A structure at the tip of the head produces an enzyme which helps the sperm to penetrate the ovum.

IV. Projects:

Question 1.
Make a list of 10 animals which show external fertlisation.
Answer:
Do it yourself

Question 2.
Make a list of five animals which show metamorphosis.
Answer:
Do it yourself