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© CBSEPracticalSkills.com Edulabz International REPRODUCTION IN ANIMALS 9 TEXTBOOK QUESTIONS AND THEIR ANSWERS Q.1. Have you seen the young ones of different animals? Try to name some of the young ones by completing the table. S. No Animal Young one 1. Human Baby 2. Cat 3. Dog 4. Butterfly 5. Hen 6. Cow 7. Frog CBSEPracticalSkills.com Chick 1 © Edulabz International © CBSEPracticalSkills.com Edulabz International Ans. S. No Animal Young one 1. Human Baby 2. Cat Kitten 3. Dog Puppy 4. Butterfly Caterpillars 5. Hen Chick 6. Cow Calf 7. Frog Tadpole Q.2. Can you tell how chicks and caterpillars are born? Ans. The chicks and caterpillars are born out of sexual reproduction and hatched from the eggs, so they are oviparous animals. Q.3. How are kittens and puppies born? Ans. Kittens and puppies are also born out of sexual reproduction as babies, so they are viviparous animals. Q.4. What purpose does the tail in a sperm serve? CBSEPracticalSkills.com 2 © Edulabz International © CBSEPracticalSkills.com Edulabz International Ans. The tail helps sperm to swim in the oviduct and to reach the egg for fertilization. Q.5. Why do fish and frogs lay eggs in hundreds whereas a hen lays only one egg at a time? Ans. Though these animals lay hundreds of eggs and release millions of sperms, all the eggs do not get fertilized and develop into new individuals. This is because the eggs and sperms get exposed to water movement, wind and rainfall. Also, there are other animals in the pond which may feed on eggs. Thus, production of large number of eggs and sperms is necessary to ensure fertilization of at least a few of them. Q.6. How could a single cell become such a big individual? Ans. The fusion of single sperm cell with single egg cell, results in the formation of fertilized egg or zygote. This zygote begins to develop into an embryo. In this process zygote divides repeatedly and form embryo. Thus, the embryo continues to develop in the uterus of the mother. It gradually develops the body parts and when the development of the fetus is completed, the mother gives birth to the baby and that baby becomes such a big individual. CBSEPracticalSkills.com 3 © Edulabz International © CBSEPracticalSkills.com Edulabz International Q.7. Can you give some example of viviparous and oviparous animals? Ans. Viviparous animals – The animals which give birth to young ones are called viviparous animals. Examples – Humen, Elephant, Horse, Cow, Buffalo, Donkey, Monkey etc. Oviparous animals – The animals which lay eggs are called oviparous animals. Examples – Duck, crow, pigeon, peacock, swan etc. Q.8. Explain the importance of reproduction in organisms. Ans. Reproduction is essential for the continuation of a species. It ensures the continuation of similar kinds of individuals, generation after generation. If reproduction does not take place, no living being would survive on earth. Special characters of an organism are carried over to its next generation through reproduction only. Q.9. Describe the process of fertilization in human beings? CBSEPracticalSkills.com 4 © Edulabz International © CBSEPracticalSkills.com Edulabz International Ans. Human beings reproduce sexually. The fertilization takes place inside female body. Males eject sperms inside female body, so, millions of sperms are transferred into the female body. The sperms swim in the oviduct with the help of their tails to reach the egg. One of the sperms may fuse with the egg. Such fusion of the egg and the sperm is called fertilization. During this process the nucleus of the sperm fuses with the nucleus of ovum forming a single nucleus. Thus zygote is formed with a single nucleus, this completes the process of fertilization. Q.10. Choose the most appropriate answer : (a) Internal fertilization occurs (i) in side the female body. (ii) outside the female body (iii) in side the male body. (iv) outside the male body. (b) A tadpole develops into an adult frog by the process of (i) fertilization CBSEPracticalSkills.com 5 (ii) metamorphosis © Edulabz International © CBSEPracticalSkills.com (iii) embedding Edulabz International (iv) budding (c) The number of nuclei present in a zygote is (i) none. (b) one. (iii) two. (iv) four. Ans. (a) (i) In female body (b) (ii) metamorphosis (c) (iii) two Q.11. Indicate whether the following statements are True (T) or False (F) : (a) Oviparous animals give birth to young ones. ( ) (b) Each sperm is a single cell. ( ) (c) External fertilization takes place in frog. ( ) (d) A new human individual develops from a cell called gamete. ( ) (e) Egg laid after fertilization is made up of a single cell. ( ) (f) Amoeba reproduces by budding. ( ) (g) Fertilization is necessary even in asexual reproduction. ( ) CBSEPracticalSkills.com 6 © Edulabz International © CBSEPracticalSkills.com Edulabz International (h) Binary fission is a method of asexual reproduction. () (i) A zygote is formed as a result of fertilization. ( ) (j) An embryo is made up of a single cell. ( ) Ans. (a) False (b) True (c) True (d) False (e) True (f) False(g) False (h) (i) True (j) False True Q.12. Give two differences between a zygote and a fetus. Ans. Zygote Foetus 1. Zygote is formed by the fertilization of sperms and ovum. 2. Zygote does not have well developed limbs. 1. Foetus is formed by the repeated division of the zygote. 2. Foetus has well developed and identifiable limbs. Q.13. Define asexual reproduction. Describe two methods of asexual reproduction in animals. Ans. The type of reproduction in which only a single parent is involved is called asexual reproduction. It takes place by different methods like budding and binary fission. Let us discuss these two methods : CBSEPracticalSkills.com 7 © Edulabz International © CBSEPracticalSkills.com Edulabz International 1. Budding – It takes place in Hydra and Bacteria. In this type of reproduction, new individuals develop from the buds of the old individual. Slowly it grows and develops into separate individual. 2. Binary fission – It takes place in amoeba. In this type of reproduction, a single organism divides into two. The nucleus of the Amoeba divides into two followed by the division of its body, each part getting one nucleus develops into separate individual. Q.14. In which female reproductive organ does the embryo get embedded? Ans. The embryo get embedded in the wall of the uterus of female body for further development. CBSEPracticalSkills.com 8 © Edulabz International © CBSEPracticalSkills.com Edulabz International Q.15. What is metamorphosis? Give examples. Ans. The transformation of the larva into an adult through drastic changes is called metamorphosis. The animals that undergo metamorphosis are – (i) Silkworm :– egg → larva (caterpillar) → pupa → adult) (ii) Frog :– egg → tadpole larva → adult) etc. Q.16. Differentiate between internal fertilization and external fertilization. Ans. Internal Fertilization 1. It takes place inside the External Fertilization It takes place outside the female body. female body. 2. Sperms are ejaculated in female’s body by the male. In external fertilization the sperms are discharged in open. 3. This is observed in human beings, hen, This is observed in frogs, cows, dogs, buffalow fish, starfish etc. etc. CBSEPracticalSkills.com 9 © Edulabz International © CBSEPracticalSkills.com Edulabz International Q.17. Complete the cross-word puzzle using the hints given below Across 1. The process of the fusion of the gametes. 6. The type of fertilization in hen. 7. The term used for bulges observed on the sides of the body of hydra. 8. Eggs are produced here. Down ward 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. CBSEPracticalSkills.com 10 © Edulabz International © CBSEPracticalSkills.com Edulabz International Ans. (1) Fertilization (2) Testis (3) Zygote (4) Oviparous (5) Binary (6) Internal (7) Buds (8) Ovary CBSEPracticalSkills.com 11 © Edulabz International