NCERT SOLUTIONS- REPRODUCTION IN ANMIALS- CHAPTER 9

Q- Explain the importance of reproduction in organisms?

Ans- Reproduction is very important for the organisms because it ensures the continuity of species generation after generation.

Q- 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. For this to happen, million of sperms from the male are transferred into the female body. The sperms swim upto the oviduct with the help of their tails and reach the egg. When they come in contact with the egg, one of the sperm may fuse with the egg. Such fusion of the egg and sperm is called fertisation. During fertilisation , the nuclei of the sperm and the egg fuse to form a single nucleus.This results in the formation of egg or zygote.

Q- Differentiate between zygote and a foetus?

Ans-   Zygote                                                                                                 foetus

It is single celled.                                                                             It is multicellular.
Zygote  is formed by the fusion                                                        foetus is formed by the repeated
of male and female gametes                                                             division of embryo and differentiation.

Q- Define asexual reproduction. Describe two methods of asexual reproduction in animals?

Ans- The type of reproduction in which only one single parent is involved is called asexual reproduction. Asexual reproduction may occur in many ways-

By budding- In hydra new individuals develop from buds. This process of asexual reproduction is called budding.

By binary fission- Amoeba reproduces by simply dividing itself into two. This type of asexual reproduction is called binary fission.

Q- In which type of female reproductive organ does the embryo get embedded.?

Ans- Uterus

Q- What is metamorphosis ? Give examples?

Ans- The drastic change that transforms a larva into  an adult is called metamorphosis. Egs- frog, silkworm, honeybee etc.

Q- Differentiate  between internal fertilisation and external fertilisation?

Internal fertilisation                            

Takes place inside the body of the female.                                  Takes place outside the body of the female.
Female lays either fertilized eggs or a complete                             female lays unfertilized egg.
individual is born.

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REPRODUCTION IN ANIMALS CHAPTER 9 CLASS 8TH

IMPORTANT KEYWORDS

Reproduction- It is the one of the important life process, which ensures the continuation of similar kinds of individuals generation after generation.

Sperms- the testes produce the male gametes called sperms.

Ova- Ovary produces females gametes called ova.

Uterus- It is the part of female reproductive system where development of embryo take place.

Fertilisation- The fusion of male gametes (sperms) and female gametes( ovum) is called fertilisation.

Zygote- During fertilisation the nuclei of the sperms and the egg are fused to form a single nucleus. This fertilised egg is called zygote.

Embroyo- The zygote divides repeatedly to give rise to a ball of cells. The cells begins to differentiate into various tissues. This developing structure is called an embryo.

Foetus-  The stage of the embryo in which all parts of the body are identifiable is known as foetus.

Bud- The outgrowth from the parent body that assumes the shape of the parent is called bud.

Binary fission-Amoeba reproduce by dividing into two. This type of asexual reproduction is called binary fission.

Sexual  reproduction- The reproduction resulting from the fusion of male gamete and female gamete is called sexual reproduction.

Internal fertilization- Fertilisation that take place inside the female body is called internal fertilisation.

External fertilisation- Fertilisation that take place outside the female body is called external fertilisation.

Oviparous- Animals which lay eggs are called oviparous.

Viviparous- Animals which give birth to young ones are called viviparous.

Budding- In this type of reproduction a bud arises from the parent body and as it matures it detaches itself from parent body to give rise to new organisms.

Metamorphosis- When a larva tranforms in adult through drastic changes is called metamorphosis.

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