NCERT Solutions for Class 8th Science

Chapter 9 – REPRODUCTION IN ANIMALS

(Complete Downloadable Chapter Solution PDF file is at the bottom of the page)

 

Q.1      Explain the importance of reproduction in organisms.

Ans     Reproduction is very important as it ensures the continuation of similar kinds of individuals, generation             after generation. In other words, it is essential for the continuation of a species.

Q.2      Describe the the process of fertilization in human beings.

Ans     The fusion of ovum and sperm is called fertilization. In human beings internal fertilization occurs in                    which fertilization takes place inside the female body. The testes produce the male gametes called sperms            and the ovary produces female gametes called ova (eggs). When sperms come in contact with an egg, one            of the sperms may fuse with the egg in the fallopian tube which results in the formation of a fertilized                egg or zygote.

Q.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.

Ans   (i) in female body

Q.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 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. ( )

           (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) Oviparous animals give birth to young ones. (F)

            Correct: Oviparous animals lay eggs.

Q.5      Give two difference between a zygote and a foetus.

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

Ans     Reproduction in which only a single parent is involved is called asexual reproduction. It occurs generally              in small animals like hydra, amoeba etc. Budding and binary fission are two methods of asexual                            reproduction.

           1. Budding – In this mode of reproduction new individuals develop from bulges called buds. It can be seen            in hydra.

           2. Binary fission – In this mode or reproduction a single cell divides itself into two. It can be seen in                      amoeba.

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

Q.8      What is metamorphosis? Give examples.

Q.9      Differentiate between internal fertilization and external fertilization.

Q.10      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

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.