NCERT Solutions for Class 8 Science Chapter 9 Reproduction in Animals

NCERT Solutions for Class 8 Science Chapter 9 Reproduction in Animals will be useful in increasing concentration skill and score better marks in the exams. It helps students do better and memorize more easily during times of intense pressure.

It will help you developing deeper into the chapters and get a vast understanding of the concepts that are applied. Chapter 8 Class 8 Science NCERT Solutions will provide a lot of relevant content, making you well versed in variety of topics and able to easily recall your ideas.

Chapter 9 Reproduction in Animals Class 8 Science NCERT Solutions

Exercises

1. Explain the importance of reproduction in organism.

Solution

The process of reproduction is essential to the existence and continuity of a species. Furthermore, it helps transmit heredity from generation to generation.

2. Describe the process of fertilisation in human beings.

Solution

Fertilisation is the first step in the reproduction process in humans. It involves the fusion of sperms and eggs. Millions of sperms are released into a female’s body, but only one sperm can fuse with the egg. Fertilisation occurs when the nucleus of the egg and the sperm fuse to form one single nucleus. As a result, the zygote forms, which is the beginning of a new human being.

3. Choose the most appropriate answer.

(a) Internal fertilization occurs:
(i) In female body.
(ii) Outside female body
(iii) In male body
(iv) Outside male body.
▶ (i) In female body.

(b) A tadpole develops into an adult frog by the process of:
(i) Fertilisation
(ii) Metamorphosis
(iii) Embedding
(iv) Budding
▶ (ii) Metamorphosis

(c) The number of nuclei present in a zygote is
(i) None
(ii) One
(iii) Two
(iv) Four
▶ (ii) One

4. 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 fertilisation takes place in frogs.
(d) A new human individual develops from a cell called gamete.
(e) Egg laid after fertilisation is made up of a single cell.
(f) Amoeba reproduces by budding.
(g) Fertilisation is necessary even in asexual reproduction.
(h) Binary fission is a method of asexual reproduction.
(i) A zygote is formed as a result of fertilisation.
(j) An embryo is made up of a single cell.

Solution

(a) False
(b) True
(c) True
(f) False
(g) False
(h) True
(d) False
(e) True
(i) True
(j) False

5. Give two differences between a zygote and a foetus.

Solution

Zygote	Foetus
Zygote is a fertilized egg formed after the fusion of the sperm and ovum.	Foetus is formed by the repeated divisions of the zygote. It is a stage that shows all the main recognizable body parts of a baby.
Zygote is made up of a single cell.	Foetus is made up of many cells.

6. Define asexual reproduction. Describe two methods of asexual reproduction in animals.

Solution

The type of reproduction in which only a single parent is involved is called asexual reproduction. Following are the two methods of asexual reproduction in animals:
(i) Binary fission: Binary fission involves almost an equal division of parent cell into two daughter cells, each of which grows into a new individual. This method of reproduction occurs regularly among protozoa like Amoeba, Paramecium, etc.
(ii) Budding: Budding is the form of asexual reproduction in which a new individual arises from a bud. The bud develops on the parent body, gets detached and grows into a separate individual, for example as in Hydra.

7. In which female reproductive organ does embryo get embedded?

Solution

The embryo gets embedded in the walls of the uterus.

8. What is metamorphosis? Give examples.

Solution

Metamorphosis is the process in which an animal undergoes a drastic change in form or structure. The transformation can be physical or behavioural, and can involve changes in size, shape, colour, physiology, or behaviour. The animals that undergoes metamorphosis are:
(i) Silkworm (egg → caterpillar → pupa → adult)
(ii) Frog (egg → tadpole → adult)

9. Differentiate between internal fertilization and external fertilization.

Solution

Internal fertilization	External fertilization
It takes place inside the female body.	It takes place outside the female body.
The fusion of male and female gametes takes place inside the female body.	The fusion of male and female gametes takes place outside the female body.
They lay eggs or give birth to young ones.	They lay eggs.
The male discharges the sperms inside the body of the female.	Both the male and female discharge their gametes in water.
Examples are cow, human, dog, monkey, etc.	Examples are : fish, frog, etc.

10. Complete the crossword puzzle using the hints given below.

Across:
1. The process of fusion of gametes.
6. The type of fertilisation in hens.
7. The term used for bulges observed on the sides of the body of Hydra.
8. Eggs are produced here.

Down:
2. Sperms are produced in these male reproductive organs.
3. Another term for the fertilised egg.
4. These animals lay eggs.
5. A type of fission in Amoeba.

Solution