8 class Chapter: Reproduction in Animals NOTES
1. Explain the importance of reproduction in organisms.
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Reproduction is the process of producing new individuals.
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It helps maintain the continuity of species.
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It increases the population of organisms.
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It ensures the survival of living organisms.
2. Describe the process of fertilisation in human beings.
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Fertilisation is the fusion of male and female gametes.
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Sperms enter the female body through the vagina.
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Sperms travel to the fallopian tube.
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The sperm fuses with the egg to form a zygote.
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The zygote divides to form an embryo, which later develops into a foetus.
3. Choose the most appropriate answer.
(a) Internal fertilisation occurs
Answer: (i) in the female body
(b) A tadpole develops into an adult frog by the process of
Answer: (ii) metamorphosis
(c) The number of nuclei present in a zygote is
Answer: (iii) two
4. Indicate whether the following statements are True (T) or False (F).
(a) Oviparous animals give birth to young ones. — False
(b) Each sperm is a single cell. — True
(c) External fertilisation takes place in the frog. — True
(d) A new human individual develops from a cell called a gamete. — False
(e) Egg laid after fertilisation is made up of a single cell. — True
(f) Amoeba reproduces by budding. — False
(g) Fertilisation is necessary even in asexual reproduction. — False
(h) Binary fission is a method of asexual reproduction. — True
(i) A zygote is formed as a result of fertilisation. — True
(j) An embryo is made up of a single cell. — False
5. Give the differences between a zygote and a foetus.
| Zygote | Foetus |
|---|---|
| Earliest stage of development | Later stage of development |
| Formed after fertilisation | Develops from embryo |
| Single cell | Has body parts formed |
| Divides to form embryo | Continues growth inside uterus |
6. Define asexual reproduction. Describe two methods of asexual reproduction in animals.
Asexual reproduction:
Reproduction from one parent without fusion of gametes.
Methods:
1. Binary fission (Amoeba)
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One cell divides into two daughter cells.
2. Budding (Hydra)
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A small bud grows on the parent body.
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The bud develops and becomes a new organism.
7. In which female reproductive organ does the embryo get embedded?
Answer: Uterus
8. What is metamorphosis? Give examples.
Metamorphosis:
A process where an animal changes its body form during development.
Examples:
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Frog
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Insects
9. Differentiate between internal fertilisation and external fertilisation.
| Internal Fertilisation | External Fertilisation |
|---|---|
| Occurs inside female body | Occurs outside female body |
| Higher survival of young | Lower survival of young |
| Example: Humans, cow, dog | Example: Fish, frog |
10. Complete the crossword puzzle.
Across
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Fertilisation
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Internal
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Buds
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Ovary
Down
2. Testis
3. Zygote
4. Oviparous
5. Binary