Reproduction In Animals

Exercises 

1. Explain the importance of reproduction in organisms.

Ans:-

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

2. Describe the process of fertilisation in human beings.

Ans:-

The first step in the process of reproduction is the fusion of a sperm and an ovum. When sperms come in contact with an egg, one of the sperms may fuse with the egg. Such fusion of the egg and the sperm is called fertilisation. During fertilisation, the nuclei of the sperm and the egg fuse to form a single nucleus that results in the formation of a fertilised egg or zygote.

3. Choose the most appropriate answer.

(a) Internal fertilisation occurs

(i) in female body.

(ii) outside female body.

(iii) in male body.

(iv) outside male body.

(b) A tadpole develops into an adult frog by the process of

(i) fertilisation         (ii) metamorphosis            (iii) embedding           (iv) budding

(c) The number of nuclei present in a zygote is

(i) none       (ii) one           (iii) two            (iv) four

4. Indicate whether the following statements are True (T) or False (F).

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

(b) Each sperm is a single cell.            (T)

(c) External fertilisation takes place in frog.           (T)

(d) A new human individual develops from a cell called gamete.    (F)

(e) Egg laid after fertilisation is made up of a single cell.    (T)

(f) Amoeba reproduces by budding.      (F)

(g) Fertilisation is necessary even in asexual reproduction.      (F)

(h) Binary fission is a method of asexual reproduction.      (T)

(i) A zygote is formed as a result of fertilisation.     (T)

(j) An embryo is made up of a single cell.     (F)

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

Ans:-

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

Ans:-

A type of reproduction in which only a single parent is involved is called asexual reproduction.

Two methods of asexual reproduction are :

1. Budding :- 

In each hydra, there may be one or more bulges. These bulges are the developing new individuals and they are called buds.These new individuals develop as outgrowths from a single parent(hydra). Since new individuals develop from the buds in hydra, this type of asexual reproduction is called budding.

2. Binary Fission :-

Another method of asexual reproduction is observed in the microscopic organism, amoeba. It begins the process of reproduction by the division of its nucleus into two nuclei. This is followed by division of its body into two, each part receiving a nucleus. Finally, two amoebae are produced from one parent amoeba. This type of asexual reproduction in which an animal reproduces by dividing into two individuals is called binary fission.

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

Ans:-

The female reproductive organ in which the embryo get embedded is - Uterus

8. What is metamorphosis? Give examples.

Ans:-

The transformation of the larva into an adult through drastic changes is called metamorphosis.

E.g. Frog, butterfly etc.

9. Differentiate between internal fertilisation and external fertilisation.

Ans:-

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

Across

1. The process of the fusion of the gametes.

6. The type of fertilisation 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 in vitro fertilisation.

4. These animals lay eggs.

5. A type of fission in amoeba.

Ans:-

Across

1. Fertilisation

6. Internal

7. Buds

8. Ovary

Down

2. Testes

3. IVF

4. Oviparous

5. Binary