Extra 30 short questions and answers from the chapter:6 "Reproduction in Animals" for Class 8 Science CBSE:-
1. What is reproduction?
Ans: Reproduction is the biological process by which living organisms produce offspring to ensure the continuity of their species.
2. What are the two main types of reproduction?
Ans: The two types of reproduction are:
Asexual reproduction
– Involves a single parent, e.g., budding in Hydra.
Sexual reproduction
– Involves two parents and gamete fusion, e.g., humans.
3. What is fertilization?
Ans: Fertilization is the fusion of a male gamete (sperm) and a female gamete (ovum) to form a zygote.
4. Differentiate between external and internal fertilization.
Ans:
External fertilization:
Takes place outside the female body, e.g., frogs, fish.
Internal fertilization:
Takes place inside the female body, e.g., humans, dogs.
5. What is a zygote?
Ans: A zygote is the single cell formed after the fusion of sperm and egg, which later develops into an embryo.
6. What is the function of the testes?
Ans: Testes produce male gametes (sperms) and the hormone testosterone.
7. What is the function of ovaries in the female reproductive system?
Ans: Ovaries produce female gametes (ova) and secrete female hormones like oestrogen and progesterone.
8. What is metamorphosis?
Ans: Metamorphosis is a biological process in which an organism undergoes drastic changes in body form during development, e.g., a tadpole changing into a frog.
9. What are oviparous and viviparous animals?
Ans:
Oviparous animals:
Lay eggs, e.g., birds, frogs.
Viviparous animals:
Give birth to live young, e.g., humans, cows.
10. What is asexual reproduction? Give an example.
Ans: Asexual reproduction is a mode of reproduction that involves a single parent without gamete fusion. Example: Budding in Hydra.
11. How does budding occur in Hydra?
Ans: In Hydra, a small bud develops on the body, grows, and eventually detaches to form a new individual.
12. How does binary fission occur in Amoeba?
Ans: In Amoeba, the nucleus divides first, followed by the division of the cytoplasm, resulting in two identical daughter cells.
13. What is the role of the placenta in pregnancy?
Ans: The placenta provides oxygen and nutrients to the developing embryo and removes waste from the embryo’s blood.
14. What is the function of the umbilical cord?
Ans: The umbilical cord connects the embryo to the placenta and helps in the exchange of nutrients and waste.
15. What happens during gestation in humans?
Ans: Gestation is the period during which the embryo develops into a fully formed baby inside the mother's womb, lasting about 9 months in humans.
16. Name the male and female gametes.
Ans:
Male gamete:
Sperm
Female gamete:
Ovum (egg)
17. What is the function of sperm?
Ans: Sperm is the male reproductive cell that carries genetic information and fuses with the egg to form a zygote.
18. What is the difference between an embryo and a fetus?
Ans:
Embryo:
The early stage of development after fertilization.
Fetus
:
The later stage of development when the body organs are formed.
19. What is puberty?
Ans: Puberty is the stage in human development when reproductive organs mature, and secondary sexual characteristics appear.
20. Name two secondary sexual characteristics in males and females.
Ans:
Males:
Growth of facial hair, deepening of voice.
Females:
Development of breasts, widening of hips.
21. How does reproduction occur in frogs?
Ans: Frogs undergo external fertilization where eggs and sperms are released in water, leading to fertilization outside the body.
22. How do reptiles reproduce?
Ans: Most reptiles reproduce by laying eggs (oviparous), and fertilization is internal.
23. Why is reproduction important for organisms?
Ans: Reproduction is essential for species survival and continuation of life on Earth.
24. What is regeneration? Give an example.
Ans: Regeneration is the process where an organism regrows lost body parts, e.g., Planaria can regenerate a complete body from its fragments.
25. What is the function of the uterus?
Ans: The uterus is the organ where the fertilized egg implants and develops into a baby.
26. Why are sperm cells motile?
Ans: Sperm cells have a tail (flagellum) that helps them swim towards the egg for fertilization.
27. What is the role of hormones in reproduction?
Ans: Hormones like testosterone (in males) and oestrogen (in females) regulate reproductive processes and secondary sexual characteristics.
28. What is the difference between identical and fraternal twins?
Ans:
Identical twins:
Develop from a single fertilized egg that splits into two embryos.
Fraternal twins:
Develop from two separate eggs fertilized by two sperms.
29. What happens during fertilization in humans?
Ans: In humans, fertilization occurs when a sperm cell fuses with an ovum in the oviduct, forming a zygote.
30. Why do animals reproduce?
Ans: Animals reproduce to ensure the survival of their species and maintain the balance of nature.
