NCERT Solutions for Class 8 Science Chapter 9 – Reproduction in animals
Orchid International School recognizes the significance of Class 8 Science Chapter 9, "Reproduction in Animals," which introduces the various methods animals employ for reproduction. It is crucial to thoroughly understand these new concepts and proficiently solve the exercise questions. To facilitate this process, we encourage students to download and consult Orchid's Class 8 Science Chapter 9 "Reproduction in Animals Solutions," meticulously prepared by subject experts. These solutions offer valuable guidance on how to formulate precise answers and enhance one's skills accordingly.
Reproduction in animals
Explain the importance of reproduction in organisms.
Importance of reproduction:
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Human reproduction is essential for the continuance of the human species.
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It is the process of producing new individuals from the living organisms.
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Reproduction ensures the passage of traits and habitats from generation to generation.
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Without reproduction the species will be vanished from the earth and there is no world without species.
Describe the process of fertilization in human beings.
Process of fertilization in human beings:
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Human reproduction is brought about by formation and fusion of the male and female gametes. The male gametes, i.e. the sperms are produced by the testis and the female gametes, i.e. the ovum is produced by the ovary.
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During copulation, the male releases sperm into the female reproductive tract. Since the sperm is a motile gamete, it will swim up the female reproductive tract to reach the ovum in the fallopian tube.
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The process of fertilization happens when the male and female gametes fuse together in the fallopian tube. The end product of fertilization is called a zygote, which will develop further and become a foetus in the womb.
Choose the most appropriate answer.
a. Internal fertilisation occurs
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In the female body.
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Outside female body.
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In male body.
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Outside male body
b. A tadpole develops into an adult frog by the process of
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Fertilisation.
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Metamorphosis
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Embedding
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Budding
c. The number of nuclei present in a zygote is
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None
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One
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Two
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Four
a . 1. In a female body
Internal fertilization takes place inside the female body and external fertilization takes place outside the female body.
b .2 . Metamorphosis
Fertilization takes place in human beings by the fusion of gametes and budding is a type of asexual reproduction takes place in parents in forming the buds.
c . 2.One
Only one nuclei is present in a zygote.
In which female reproductive organ does the embryo get embedded?
The embryo gets embedded in the wall of the uterus for further development.
Indicate whether the following statements are true (T) or false (F).
a. Oviparous animals give birth to young one.
b. Each sperm is a single cell.
c . External fertilisation takes place in frogs.
d . A new human individual develops from a cell called gamete.
e .Egg laid after fertilisation is made up of a single cell.
f . Amoeba reproduces by budding.
g . Fertilisation is necessary even in asexual reproduction.
h . Binary fission is a method of asexual reproduction.
i . A zygote is formed as a result of fertilisation.
j . An embryo is made up of a single cell.
a. F
b. T
c.T
d.T
e.T
f.F
g.T
h.T
i.T
j. F
Give two differences between a zygote and Foetus.
Difference between zygote and foetus:
|
Zygote |
Foetus |
|
Zygote is the single cell resulting from fusion of ovum and sperm. |
Foetus is the much-developed form of zygote which has body parts and body organs. |
|
It is generally observed in the fallopian tube of the female |
The foetus is a much-developed version of a baby present in the uterus. |
Define asexual reproduction. Describe two methods of asexual reproduction in animals.
Asexual Reproduction:
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It is a mode of reproduction that does not entails the union of sex cells or gametes.
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There are different types of asexual reproduction, they are binary fission, budding vegetative propagation, spore formation, fragmentation. There is no gamete formation in this type of reproduction. Animals like Hydra, Amoeba undergo asexual mode of reproduction.
Two types of Asexual reproduction are:
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Budding: It is a type of asexual reproduction in which a new organism develops from an outgrowth or bud due to cell division at one particular site. These buds develop into tiny individuals and when fully they mature and detach from the parets body and become a new independent individual. Example: Hydra.
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Binary Fission: In this type of asexual reproduction the body of the organism mainly unicellular organism divides into two. Each of the two daughter cells are alike. Example: Amoeba.
What is metamorphosis? Give examples.
Metamorphosis:
It means sudden change which happens while developing.
The animals that undergoes metamorphosis are
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Butterfly (egg🡪larva🡪pupa🡪adult)
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Frog (egg🡪tadpole🡪adult)
Difference between internal fertilisation and external fertilisation.
Difference between internal fertilization and external fertilization:
|
Internal Fertilisation |
External Fertilisation |
|
The fertilisation takes place inside the female body. Union of male and female gametes occur in the female body after copulation. Example- human beings, reptiles, birds. |
The fertilisation takes place outside the body of the female. Union of male and female gametes occur outside the female body. Example- frog, fish and some of the algae etc. |
Complete the crossword puzzle using the hints given below. Across
1. The process of the fusion of the zygotes.
6. The type of fertilisation in hen.
7. 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.
1. The process of the fusion of the zygotes - FERTILIZATION
6. The type of fertilisation in hen - INTERNAL
7. Term used for bulges observed on the sides of the body of hydra - BUDS
8. Eggs are produced here - OVARY
Down
2. Sperms are produced in these male reproductive organs - TESTES
3. Another term for the fertilized egg - ZYGOTE
4. These animals lay eggs - OVIPAROUS
5. A type of fission in amoeba – BINARY
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