Reproduction in Animals Class 8 Question Answers

Reproduction in Animals is Chapter 4 taken from the JKBOSE textbook of Science for students of Class 8th. In the previous post, I provided you with Questions and Answers for Chapter 3 Conservation of Plants and Animals. This post is about the Reproduction in Animals Class 8 Question Answers. Before we move on to solutions you must have your basics clear. So, let me begin by giving you a brief overview of what you have studied in this chapter.

Reproduction in Animals Class 8 Question Answers

Overview of Chapter

• MODES OF REPRODUCTION.
• SEXUAL REPRODUCTION.
• MALE REPRODUCTIVE ORGANS.
• FEMALE REPRODUCTIVE ORGANS.
• FERTILIZATION.
• DEVELOPMENT OF EMBRYO.
• VIVIPAROUS AND OVIPAROUS ANIMALS.
• YOUNG ONES TO ADULTS.
• ASEXUAL REPRODUCTION.

MODES OF REPRODUCTION: The process by which living beings produce new young ones of their kind is termed Reproduction.  Reproduction is not essential for the survival of living organisms on earth but is important for the continuity of life on earth. There are two main of reproduction:

• a) Asexual Reproduction
• b) Sexual Reproduction.

SEXUAL REPRODUCTION: In sexual reproduction, a new young one is produced by the fusion of male and female gametes. The two parents take part in sexual reproduction. The male produces male gametes called sperm cells while the female produces female gametes called egg cells. These gametes fuse to form a zygote which develops into a new individual.

MALE REPRODUCTIVE ORGANS: The male reproductive system consists of a pair of testes, two sperm ducts, a scrotal sac, epididymis, seminal vesicles and a penis. Sperms are produced inside the testes and stored in a coiled tube-like structure called the epididymis. The sperm are transferred into the female body with the help of the penis.

FEMALE REPRODUCTIVE ORGANS: The female reproductive system consists of a pair of oval-shaped organs called ovaries, oviducts, uterus and vagina. It produces female gametes, ova or egg and female sex hormones. The egg produced by the ovary is carried to the uterus by the Fallopian tube which is the site for fertilisation. The uterus is the place where the development of the embryo takes place whereas the vagina is the opening which receives sperm from the male.

FERTILIZATION: The process of fusion of male gamete and female gamete to form a zygote is called fertilisation. If fertilisation takes place inside the body of a female, it is called internal fertilisation and if it takes place outside the body of a female, it is termed external fertilisation.

DEVELOPMENT OF EMBRYO: The zygote travels down the oviduct and divides repeatedly to form a ball of cells. The cells begin to form groups that finally develop into different tissues and organs of the body. This developing structure is termed an embryo which gets embedded in the wall of the uterus (implantation) where further development takes place.

VIVIPAROUS AND OVIPAROUS ANIMALS: The animals which directly give birth to their young ones while the animals which reproduce by laying eggs are called oviparous animals.

YOUNG ONES TO ADULT: During the development from a new individual to an adult, continuous growth occurs with considerable changes in body structure. In some animals, the young ones look very different from the adults. The transformation of the larva into an adult through drastic changes is called metamorphosis.

ASEXUAL REPRODUCTION: In asexual reproduction, a new young one is produced from a single parent without the fusion of gametes. Binary fission and budding are two main forms of asexual reproduction. In fission single individual gets divided to form two new individuals which develop into two new organisms. In budding, a bulge or bud develops on the parent body. The bud enlarges and gets detached from the parent and develops into a new organism that can live independently.

Reproduction in Animals Class 8 Questions.

Exercises

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

1. Oviparous animals give birth to young ones. (False)
2. Each sperm is a single cell. (True)
3. External fertilization takes place in the frog. (True)
4. A new human individual develops from a cell called a gamete.  (False)
5. Egg laid after fertilization is made up of a single cell. (True)
6. Amoeba reproduces by budding. (False)
7. Fertilization is necessary even in asexual reproduction. (False)
8. Binary fission is a method of asexual reproduction. (True)
9. A zygote is formed as a result of fertilization. (True)
10. An embryo is made up single cell. (False)

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

Ans.

Zygote	Foetus
1. It is formed by the fusion of male and female gametes (egg and sperm)	1. It is formed by the growth and development of an embryo.
2. It is a single-celled structure.	2. It is a multicellular structure.
3. Zygote has no body parts.	3. Foetus has all body parts.
4. Zygote is the beginning of the baby's formation.	4. Foetus is an unborn baby in the later stages of development.

6. Define asexual reproduction. Describe two methods of sexual reproduction.

Ans. It is a type of reproduction in which a new individual is formed from a single parent without the fusion of gametes. The individual so formed is identical to the parent. It does not need both male and female individuals. The two common methods of asexual reproduction are: –

(1) Budding     (2) Fission.

1. Budding: – It is the type of asexual reproduction in which a bud or bulge develops on a parent body. This bud/bulge enlarges gets detached from the parent body and develops into an identical new individual which lives independently. E.g. Budding in Hydra.
2. Fission: – It is the type of asexual reproduction in which the parent body is divided into two or more new cells. The division of both the nucleus and cytoplasm takes place. All the new cells so formed develop into a new individual. Depending upon the number of individuals formed fission can be Binary (two individuals) or Multiple (more than two individuals). E.g. Fission in Amoeba.

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

Ans. The embryo gets embedded in the wall of the uterus of a female for further development.

8. What is metamorphosis? Give examples.

Ans. The process of drastic changes which takes place during the transformation of the zygote into an adult is termed metamorphosis. E.g. Life cycle of a frog and the life cycle of a silkworm.

9. Differentiate between internal fertilization and external fertilization.

Ans. 

Internal Fertilization	External Fertilization
1. This type of fertilization takes place inside the body of the female.	1. This type of fertilization takes place outside the body of the female.
2. Male release the sperms inside the female body.	2. Both sperm and egg are released outside the body of the female.
3. Generally development of an embryo takes place inside the body of the female.	3. The development of the embryo takes place outside the body of the female.
4. It is very common in land animals. E.g. Humans, Cattle, Cats, Dogs etc.	4. It is very common in aquatic animals. E.g. fishes, frogs, crocodiles etc.

10. Complete the word puzzle.

Across	Down
1. The process of fusion of gametes.	2. Sperms are produced in these male organs.
6. The type of fertilization in the hen.	3. Another term for a fertilized egg.
7. The term used for bulge observed on the body of Hydra.	4. These animals lay eggs.
8. Eggs are produced here.	5. A type of fission in amoeba.

Ans.

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