Students – welcome to Chapter 6! We have posted the perfect Chapter 6 solutions materials here for you to study. All the exercise questions, extended learning activities, in-text questions and activities for this chapter have been answered in this material. We have also included extra questions for your benefit. If you study this material in detail, you will be thoroughly prepared for your exams.
Solutions to Exercises (Page No 76) of NCERT Class 8 Science Chapter 6 Reproduction in Animals
1. Explain the importance of reproduction in organisms.
Answer:
The importance of reproduction in organisms is that it is essential for the continuation of a species. Without reproduction a species would become extinct. Reproduction is very important as it ensures the continuation of similar kinds of individuals, generation after generation.
2. Describe the process of fertilisation in human beings.
Answer:
The process of fertilisation in human beings starts when male sperms come into contact with a female egg or ovum, resulting in fusion. Fusion of the egg and the sperm is called fertilisation. During fertilization, the nuclei of the sperm and the egg fuse to form a single nucleus. This results in the formation of a fertilized egg or zygote.
3. Choose the most appropriate answer.
(a) Internal fertilisation occurs
(i) in the female body
(ii) outside the female body
(iii) in male body
(iv) outside male body
Answer: Internal fertilisation occurs(i) in the female body.
(b) A tadpole develops into an adult frog by the process of
(i) fertilisation (ii) metamorphosis (iii) embedding (iv) budding
Answer: A tadpole develops into an adult frog by the process of (ii) metamorphosis.
(c) The number of nuclei present in a zygote is
(i) none (ii) one (iii) two (iv) four
Answer: The number of nuclei present in a zygote is (iii) two.
4. 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 fertilisation takes place in the frog. ( )
(d) A new human individual develops from a cell called a 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. ( )
Answers:
(a) Oviparous animals give birth to young ones. ( )
False. Oviparous animals lay eggs, which hatch to form new animals. Viviparous animals give birth to young ones.
(b) Each sperm is a single cell. ( )
True. Each sperm is a single cell with all the usual cell components.
(c) External fertilisation takes place in the frog. ( )
True. Male and female frogs come together in water and the female lays hundreds of eggs. Then the male deposits sperms over them. The sperms come into contact with the eggs in water, which results in fertilisation.
(d) A new human individual develops from a cell called a gamete. ( )
False. A new human individual develops from a cell called a zygote. The zygote is formed by the fusion of the female gamete egg and male gamete sperm.
(e) Egg laid after fertilisation is made up of a single cell. ( )
False. Egg laid after fertilisation (such as in hen) is made up of multiple cells. Soon after fertilisation, the zygote divides repeatedly, travels down the oviduct and the egg is formed. Since the zygote divides repeatedly, the egg is made up of multiple cells.
(f) Amoeba reproduces by budding. ( )
False. Amoeba does not reproduce by budding. Amoeba reproduces by division of its body into two by a process called binary fission.
(g) Fertilisation is necessary even in asexual reproduction. ( )
False. Fertilisation does not occur in asexual reproduction. In asexual reproduction the offspring is formed from a single parent and retains the characteristics of that parent. Fertilisation involving two parents does not happen.
(h) Binary fission is a method of asexual reproduction. ( )
True. Binary fission is a method of asexual reproduction by which an organism divides its body into two to form two new individuals.
(i) A zygote is formed as a result of fertilisation. ( )
True. A zygote is formed as a result of fertilisation when the male gamete called sperm and female gamete called egg fuse to form a zygote.
(j) An embryo is made up of a single cell. ( )
False. After fertilisation the zygote divides repeatedly into to give rise to a ball of cells, which form the embryo. Therefore, the embryo is multicellular.
5. Give two differences between a zygote and a foetus.
Answer:
Zygote is formed during fertilisation when the male gamete called sperm fuses with the female gamete called egg. On the other hand, a foetus is the advanced stage of an embryo, which is actually formed from the zygote. A zygote is single-celled whereas a foetus is multicellular.
6. Define asexual reproduction. Describe two methods of asexual reproduction in animals.
Answer:
Asexual reproduction is the mode of reproduction in which the offspring arises from a single parent and fusion of male and female gametes does not occur. The offspring retains the characteristics of that parent. Two methods of asexual reproduction in animals are budding and binary fission.
(i) Budding: In budding, one or more outgrowths called buds emerge from the body of the parent. New individuals develop from these outgrowths and get separated from the parent. An organism which reproduces via budding is called Hydra.
(ii) Binary Fission: In binary fission, a single parent nucleus divides into two nuclei. This is followed by division of its body into two, each part receiving a nucleus. Each part develops into a new organism. An organism which reproduces via binary fission is called Amoeba.
7. In which female reproductive organ does the embryo get embedded?
Answer:
The female reproductive organ in which the embryo get embedded is the uterus. The embryo gets embedded in the wall of the uterus for further development. It gradually develops body parts such as hands, legs, eyes etc and is called a foetus.
8. What is metamorphosis? Give examples.
Answer:
The transformation of the larva into an adult with different features through drastic changes in the body is called metamorphosis. For example, the silkworm larva turns into a pupa which grows in an adult silkmoth by the process of metamorphosis. Also, a tadpole turns into an adult frog by the process of metamorphosis.
9. Differentiate between internal fertilisation and external fertilisation.
Answer:
Internal fertilisation takes place inside the female body and external fertilisation takes place outside the female body. Since internal fertilisation takes place in a protected environment inside the body, there is high chance of survival of offspring. In external fertilisation, there is low chance of survival of offspring due to exposure to harsh environments.
Examples of internal fertilisation are humans, hens, dogs, etc. Examples of external fertilisation are frogs, fish, starfish.
10. Complete the crossword puzzle using the hints given below.
Across
1. The process of the fusion of the gametes.
6. The type of fertilisation in hen.
7. The 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 in vitro fertilisation.
4. These animals lay eggs.
5. A type of fission in amoeba
Answer:
The solution to the crossword puzzle is shown below:
Solutions to Extended Learning – Activities and Projects (Page No 77) of NCERT Class 8 Science Chapter 6 Reproduction in Animals
1. Visit a poultry farm. Talk to the manager of the farm and try to find out the answers to the following.
(a) What are layers and broilers in a poultry farm?
(b) Do hens lay unfertilised eggs?
(c) How can you obtain fertilised and unfertilised eggs?
(d) Are the eggs that we get in the stores fertilised or unfertilised?
(e) Can you consume fertilised eggs?
(f) Is there any difference in the nutritional value of fertilised and unfertilised eggs?
Answers:
Solution to Extended Learning Problem 1
2. Observe live hydra yourself and learn how they reproduce by doing the following activity: During the summer months collect water weeds from ponds or ditches along with the pond water and put them in a glass jar. After a day or so you may see several hydra clinging to the sides of the jar. Hydra is transparent, jelly-like and with tentacles. It clings to the jar with the base of its body. If the jar is shaken, the hydra will contract instantly into a small blob, at the same time drawing its tentacles in. Now take out few hydras from the jar and put them on a watch glass. Using a hand lens or a binocular or dissection microscope, observe the changes that are taking place in their body. Note down your observations.
Answer:
Solution to Extended Learning Problem 2
3. The eggs we get from the market are generally the unfertilised ones. In case you wish to observe a developing chick embryo, get a fertilised egg from the poultry or hatchery which has been incubated for 36 hours or more. You may then be able to see a white disc-like structure on the yolk. This is the developing embryo. Sometimes if the heart and blood vessels have developed you may even see a red spot.
Answer:
Solution to Extended Learning Problem 3
4. Talk to a doctor. Find out how twinning occurs. Look for any twins in your neighbourhood, or among your friends. Find out if the twins are identical or non-identical. Also find out why identical twins are always of the same sex? If you know of any story about twins, write it in your own words.
Answer:
Solution to Extended Learning Problem 4
Solutions to In Text Questions of NCERT Class 8 Science Chapter 6 Reproduction in Animals
1. (Page 66). Have you seen the young ones of different animals? Try to name some of the young ones by completing Table 6.1 shown in examples at S. No. 1 and 5.
Answer:
The completed table is shown below:
Table 6.1
| S. No. | Animals | Young one |
| 1. | Human | Baby |
| 2. | Cat | Kitten |
| 3. | Dog | Puppy |
| 4. | Butterfly | Larva |
| 5. | Hen | Chick |
| 6. | Cow | Calf |
| 7. | Frog | Tadpole |
2. (Page 66) You will remember that plants that reproduce sexually have male and female reproductive parts. Can you name these parts?
Answer:
The male reproductive part is the stamen and the female reproductive part is the pistil, both occurring in the flower of the plant.
3. (Page 67) What purpose does the tail in a sperm serve?
Answer:
The tail in a sperm serves to move the sperm forward using whip-like back-and-forth movements. This is how the sperm moves forward into the uterus to fertilize the female egg.
4. (Page 70) How could a single cell become such a big individual?
Answer:
A single cell could become such a big individual because of cell division. Fertilisation results in the formation of a single-celled zygote which divides repeatedly and develops into different tissues and organs of the body.
5. (Page 72) What about the changes that we observe in our body as we grow? Do you think we too undergo metamorphosis?
Answer:
No, humans do not undergo metamorphosis. In human beings, body parts similar to those present in the adults are present from the time of birth.
Solutions to All Activities of NCERT Class 8 Science Chapter 6 Reproduction in Animals
1. Complete Activity 6.1 (Page 69). Visit some ponds or slow-flowing streams during spring or rainy season. Look out for clusters of frog’s eggs floating in water. Write down the colour and size of the eggs.
Answer:
2. Complete Activity 6.2 (Page 71). Try to observe eggs of the following organisms – frog, lizard, butterfly or moth, hen and crow or any other bird. Were you able to observe eggs of all of them? Make drawings of the eggs that you have observed.
Answer:
3. Complete Activity 6.3 (Page 73). Get permanent slides of hydra. Observe them using hand lens or a microscope. Look out for any bulges from the parent body. Count the number of bulges that you see in different slides. Also, note the size of the bulges. Draw the diagram of hydra, as you see it. Compare it with the Fig. 6.11.
Answer:
Extra Questions to Complement Solutions to NCERT Class 8 Science Chapter 6 Reproduction in Animals
Very Short Answer Type:
1. Name the type of reproduction that takes place in humans.
Answer:
Sexual reproduction.
2. Which organ produces sperms?
Answer:
Testes.
3. Where does fertilisation take place?
Answer:
Oviducts or fallopian tubes.
4. Name an animal which reproduces via external fertilisation.
Answer:
Frog.
5. Name a single-celled organism which reproduces by division of its nucleus.
Answer:
Amoeba.
6. Name the form of reproduction that occurs via a single parent.
Answer:
Asexual reproduction.
7. What is the term of a fertilized egg?
Answer:
Zygote.
8. How long does it take for the embryo in a hen’s egg to develop into a chick?
Answer:
3 weeks.
9. How many sperms are produced by the testes?
Answer:
Millions of sperms.
10. Name the process by which a tadpole develops into a frog.
Answer:
Metamorphosis.
Multiple Choice Questions (MCQ):
1. The development of the baby happens in the:
(a) Fallopian tube
(b) Uterus
(c) Ovary
(d) Ovum
Answer: (b) Uterus
2. Name the stage in the life cycle of a silkmoth right before the moth is formed
(a) Pupa
(b) Caterpillar
(c) Cocoon
(d) Egg
Answer: (a) Pupa
3. In human beings, after fertilisation, the structure which gets embedded in the wall of uterus is
(a) ovum
(b) embryo
(c) foetus
(d) zygote
Answer: (b) embryo
4. In human beings, the correct sequence of events during reproduction is (NCERT Exemplar)
(a) gamete formation, fertilisation, zygote, embryo
(b) embryo, zygote, fertilisation, gamete formation
(c) fertilisation, gamete formation, embryo, zygote
(d) gamete formation, fertilisation, embryo, zygote
Answer: (a)
5. Which of the following is true about frog’s eggs:
(a) They lay hundreds of eggs and they all hatch
(b) They lay hundreds of eggs and most die on their own
(c) They lay hundreds of eggs and most are destroyed by the elements and animals
(d) They lay hundreds of eggs and most fail to hatch because of the weather
Answer: (c)
Short Answer Type:
1. Give one way in which reproduction in plants and animals is similar.
Answer:
In both plants and animals male and female gametes fuse to form a zygote.
2. Name the three parts of the male reproductive system.
Answer:
The male reproductive organ includes a pair of testes, two sperm ducts and a penis.
3. Name one common characteristic of a sperm and an egg.
Answer:
They are both single cells.
4. What is ovulation?
Answer:
Ovulation is process of release of mature egg from the ovary.
5. Why does an offspring inherit characteristics of both parents?
Answer:
The process of fertilisation is the meeting of an egg cell from the mother and a sperm cell from the father. So, the new individual inherits some characteristics from the mother and some from the father.
6. How is the egg formed from the zygote in a hen?
Answer:
Soon after fertilisation, the zygote divides repeatedly and travels down the oviduct. As it travels down, many protective layers are formed around it. The hard shell that you see in a hen’s egg is one such protective layer.
7. Why are some women unable to bear babies? What is the solution for this?
Answer:
In some women oviducts are blocked. These women are unable to bear babies because sperms cannot reach the egg for fertilisation. The solution is IVF or in vitro fertilisation where fertilisation happens outside the body and the zygote is placed inside the mother’s uterus for further development.
8. Frog’s eggs are laid in water and do not have a shell. How do they survive?
Answer:
Although the frog’s eggs do not have a shell, a layer of jelly holds the eggs together and provides protection to the eggs.
9. What is cloning?
Answer:
Cloning is the production of an exact copy of a cell, any other living part, or a complete organism.
10. Why did Dolly not show any characteristics of the Scottish blackface ewe?
Answer:
Dolly did not show any characteristics of the Scottish blackface ewe because the nucleus of the egg from the Scottish blackface ewe was removed and replaced with the nucleus from the mammary gland cell of the Finn Dorsett sheep. The nucleus determined the organism’s characteristics.
Long Answer Type:
1. Describe the main stages of reproduction in humans.
Answer:
The main stages of reproduction in humans are as follows:
(i) In females the ovary produces eggs which are released into the oviduct.
(ii) The male sperm fuses with the egg in the oviduct.
(iii) This results in the formation of the zygote.
(iv) The zygote divides repeatedly to give rise to a ball of cells and develops into an embryo.
(v) The embryo gets embedded in the wall of the uterus for further development.
(vi) The embryo gradually develops hands, legs, head, eyes, ears etc and forms a foetus.
(vii) When the development of the foetus is complete, the mother gives birth to the baby.
Fill in the Blanks:
foetus, internal, cloned, one, viviparous, oviparous, external
(a) The number of nuclei in an ovum is __________.
(b) An advanced stage of the embryo is called the __________.
(c) The dog is an example of a _________ animal and the hen is an example of a _________ animal.
(d) Cows reproduce via _________ fertilisation and starfish reproduce via _________ fertilisation.
(e) Many-a-time _________ animals are found to be born with abnormalities.
Answers:
(a) The number of nuclei in an ovum is one.
(b) An advanced stage of the embryo is called the foetus.
(c) The dog is an example of a viviparous animal and the hen is an example of a oviparous animal.
(d) Cows reproduce via internal fertilisation and starfish reproduce via external fertilisation.
(e) Many-a-time cloned animals are found to be born with abnormalities.
Match and Pair:
| Column A | Column B |
| (i) Frog | (a) Budding |
| (ii) Hydra | (b) Test-tube babies |
| (iii) IVF | (c) Ian Wilmut |
| (iv) Mammals | (d) Metamorphosis |
| (v) Cloning | (e) Viviparous |
Answer:
| Column A | Column B |
| (i) Frog | (d) Metamorphosis |
| (ii) Hydra | (a) Budding |
| (iii) IVF | (b) Test-tube babies |
| (iv) Mammals | (e) Viviparous |
| (v) Cloning | (c) Ian Wilmut |
++++++++++++++
Frequently Asked Questions (FAQs) on NCERT Solutions to Class 8 Science Chapter 6 Reproduction in Animals
We have answered all Chapter 6 exercise questions, extended learning activities, in-text questions, in-text activities and even self-designed extra questions, in a scientific manner to help you understand the material. If you study this solutions package in detail, you will be thoroughly prepared for your exams.
The free PDFs of the solutions are also available for download anytime! If you like our study material and want more from us, keep visiting our website and subscribe to our email list.
The following topics are covered:
6.1 – Modes of Reproduction
6.2 – Sexual Reproduction
6.3 – Asexual Reproduction
3. How many problems are there in the exercises for NCERT Solutions for Class 8 Science Chapter 6 Reproduction in Animals?
Here are the number of problems for the chapter:
(i) 6 Short Answer Type Questions (Questions 1, 2, 5, 7, 8, 9)
(ii) 1 Multiple Choice Question (Question 2)
(iii) 1 Long Answer Type Questions (Question 6)
(iv) 1 Word Game-based Question (Question 10)
Yes indeed! Feel free to download the PDF versions of educationroundtheworld.com’s NCERT Solutions for Class 8 Science Chapter 6 Reproduction in Animals anytime for free! The entire material is included in the PDF version. Please look towards the top of the page to find the download button!
Study sexual reproduction in humans in detail as you will see questions from this portion in your exams. Apart from that study asexual reproduction in amoeba and hydra as they are important for your exams. We included all the other important parts of the chapter in this solutions material, so study it in detail.
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