NCERT Class VIII Science Solutions: Chapter 9-Reproduction in Animals Part 5

Download PDF of This Page (Size: 245K)

Question 26:

Hens and frogs are both oviparous exhibiting different types of fertilisation. Explain.

Answer:

Hens are oviparous in which internal fertilisation takes place. The fertilised egg develops into an embryo inside the body. However, the development of chick from the embryo takes place outside the body.

Frogs are oviparous in which both fertilisation and development of zygote to embryo and young ones occurs outside the body.

Question 27:

Observe the following figures.

  1. Result forthe embryo that would take place after it gets embedded in the uterus.

    Embryo Embedded in the Uterus.

    Result forthe embryo that would take place after it gets embedded in the uterus.

  2. Result forthe developing embryo passes to reach the uterus.

    The Developing Embryo Passes to Reach the Uterus.

    Result forthe developing embryo passes to reach the uterus.

  3. Result for The part which produces female gametes.

    The Part Which Produces Female Gametes.

    Result for The part which produces female gametes.

Result for The part where development of the baby takes place.

The Part Where Development of the Baby Takes Place.

Result for The part where development of the baby takes place.

  1. Identify the stages a to d in Fig during development of human baby.

  2. Arrange the stages in correct sequence of development.

  3. Explain the development that takes place in any one stage.

Answer:

    1. Embedding of the embryo in the uterus.

    2. Fertilisation.

    3. Zygote formation and development of an embryo from the zygote.

    4. Zygote showing fusion of nuclei.

  1. The correct sequence is c, b, d, a

  2. Zygote formation

    The sperm and the egg nuclei fuse to form a single nucleus resulting in the formation of a fertilised egg or zygote.

    (Note: One step is explained as an example. Students may explain any other step.)