{"id":25500,"date":"2021-06-23T11:49:43","date_gmt":"2021-06-23T06:19:43","guid":{"rendered":"https:\/\/mcq-questions.com\/?p=25500"},"modified":"2022-03-02T10:36:20","modified_gmt":"2022-03-02T05:06:20","slug":"ncert-solutions-for-class-8-science-chapter-9","status":"publish","type":"post","link":"https:\/\/mcq-questions.com\/ncert-solutions-for-class-8-science-chapter-9\/","title":{"rendered":"NCERT Solutions for Class 8 Science Chapter 9 Reproduction in Animals"},"content":{"rendered":"

These NCERT Solutions for Class 8 Science<\/a> Chapter 9 Reproduction in Animals Questions and Answers are prepared by our highly skilled subject experts to help students while preparing for their exams.<\/p>\n

Reproduction in Animals NCERT Solutions for Class 8 Science Chapter 9<\/h2>\n

Class 8 Science Chapter 9 Reproduction in Animals Textbook Exercise Questions and Answers<\/h3>\n

Page 110-111<\/span><\/p>\n

Question 1.
\nExplain the importance of reproduction in organisms.
\nAnswer:
\nReproduction is very important for the organisms. The organisms reproduce to generate young ones like them. It helps to maintain their existence generation after generation. If reproduction does not take place, no living being will survive on the earth. Had the process of reproduction not been there, all the plants and animals would have become extinct. Secondly, special characters of an organism are carried over to its next generation through reproduction only.<\/p>\n

Question 2.
\nDescribe the process of fertilisation in human beings.
\nAnswer:
\nThe mode of reproduction in human beings is sexual reproduction. Ovaries in females produce ova while the testes in males produce sperms. Millions of sperms are ejected inside the female reproductive tract where one of them fuses with the ovum and forms zygote. This process is known as internal fertilisation. The zygote, then, begins to develop into an embryo which attaches to the female uterus wall.<\/p>\n

Question 3.
\nChoose the most appropriate answer:
\na. Internal fertilisation occurs
\n(i) in female body
\n(ii) outside female body
\n(iii) in male body
\n(iv) outside male body
\nAnswer:
\n(i) in female body<\/p>\n

b. A tadpole develops into an adult frog by the process of
\n(i) fertilisation
\n(ii) metamorphosis
\n(iii) embedding
\n(iv) budding
\nAnswer:
\n(ii) metamorphosis<\/p>\n

c. The number of nuclei present in a zygote is
\n(i) none
\n(ii) one
\n(iii) two
\n(iv) four
\nAnswer:
\n(ii) one<\/p>\n

Question 4.
\nIndicate whether the following statements are True (T) or False (F):
\na. Oviparous animals give birth to young ones. ( )
\nb. Each sperm is a single cell. ( )
\nc. External fertilisation takes place in frog. ( )
\nd. A new human individual develops from a cell called gamete. ( )
\ne. Egg laid after fertilisation is made up of a single cell. ( )
\nf. Amoeba reproduces by budding. ( )
\ng. Fertilisation is necessary even in asexual reproduction. ( )
\nh. Binary fission is a method of asexual reproduction. ( )
\ni. A zygote is formed as a result of fertilisation. ( )
\nj. An embryo is made up of a single cell. ( )
\nAnswer:
\na. False
\nb. True
\nc. True
\nd. False
\ne. False
\nf. False
\ng. False
\nh. True
\ni. True
\nj. False<\/p>\n

\"NCERT<\/p>\n

Question 5.
\nGive two differences between a zygote and a foetus.
\nAnswer:<\/p>\n\n\n\n\n\n
Zygote<\/td>\nFoetus<\/td>\n<\/tr>\n
a. It is formed after the fusion of the sperm with the egg cell.<\/td>\na. It is a mature stage of the embryo that shows all the main recognisable body parts resembling a mature organism.<\/td>\n<\/tr>\n
b. The zygote divides several times to ^ form an embryo.<\/td>\nb. An embryo gradually develops into a foetus.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Question 6.
\nDefine asexual reproduction. Describe two methods of asexual reproduction in animals.
\nAnswer:
\nWhen a single parent is involved in reproduction and gametes are not formed, it is called asexual reproduction. Two methods of asexual reproduction are as follows:<\/p>\n

i. Budding: Budding involves the formation of a new individual from the bulges or outgrowths, known as buds, formed on the parent body. This method of reproduction is common in Hydra. In Hydra, the cells divide rapidly at a specific site and develops into an outgrowth, called the bud. These buds, while being attached to the parent plant, develop into smaller individuals. When these individuals become mature enough, they detach from the parent\u2019s body and become independent individuals.
\n\"NCERT<\/p>\n

ii. Binary Fission: It is a type of asexual reproduction in which a single cell divides into two halves. Organisms that reproduce through binary fission are bacteria and Amoeba. In Ainoeba, the division of cells can take place in any plane. It involves the division of its nucleus into two nuclei, which is followed by the division of the cytoplasm into two halves. Each half of the body receives a nucleus.
\n\"NCERT<\/p>\n

Question 7.
\nIn which female reproductive organ does the embryo get embedded?
\nAnswer:
\nThe embryo gets embedded in the wall of the uterus. The embryo, while it is still attached to the uterus, gradually develops the various body parts such as hands, legs, head, eyes, etc. The embryo at this stage is called a foetus.<\/p>\n

Question 8.
\nWhat is metamorphosis? Give examples.
\nAnswer:
\nIn case of indirect development, the transformation of the young ones into an adult through drastic changes is called metamorphosis. Larva of butterfly undergoes metamorphosis to become a butterfly. A tadpole undergoes metamorphosis to become a frog.
\n\"NCERT
\nThe tadpole that emerges from the egg contains gills, a tail and a small circular mouth. It can swim freely in water. The tadpole grows and undergoes abrupt changes in its structure and develops into a mature frog. A tadpole\u2019s metamorphosis begins with the development of limbs, lung development and finally the absorption of the tail by the body.<\/p>\n

\"NCERT<\/p>\n

Question 9.
\nDifferentiate between internal fertilisation and external fertilisation.
\nAnswer:<\/p>\n\n\n\n\n\n\n
\n

Internal fertilisation<\/p>\n<\/td>\n

\n

External fertilisation<\/p>\n<\/td>\n<\/tr>\n

a. It involves the fusion of the male and the female gamete inside the female body.<\/td>\na. It involves the fusion of the male and the female gamete outside the female body.<\/td>\n<\/tr>\n
b. Chances of the survival of offspring are more. Therefore, a small number of eggs are produced.<\/td>\nb. Chances of the survival of the eggs are less. Therefore, a large number of eggs are produced.<\/td>\n<\/tr>\n
c. Humans, cows, hens, etc., are various organisms showing internal fertilisation.<\/td>\nc. Fish, frog, starfish, etc., are the organisms showing external fertilisation.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Question 10.
\nComplete the crossword puzzle using the hints given below.
\nAcross
\n1. The process of the fusion of the gametes.
\n6. The type of fertilisation in hen.
\n7. The term used for bulges observed on the sides of the body of Hydra.
\n8. Eggs are produced here.
\nDown
\n2. Sperms are produced in these male reproductive organs.
\n3. Another term for in-vitro fertilisation.
\n4. These animals lay eggs.
\n5. A type of fission in
\n\"NCERT
\nAnswer:
\n1. Fertilisation
\n2. Testes
\n3. IVF
\n4. Oviparous
\n5. Binary
\n6. Internal
\n7. Buds
\n8. Ovary<\/p>\n

NCERT Extended Learning Activities and Projects<\/span><\/p>\n

Question 1.
\nVisit a poultry farm. Talk to the manager of the farm and try to find out the answers to the following.
\na. What are layers and broilers in a poultry farm?
\nb. Do hens lay unfertilised eggs?
\nc. How can you obtain fertilised and unfertilised eggs?
\nd. Are the eggs that we get in the stores fertilised or unfertilised?
\ne. Can you consume fertilised eggs?
\nf. Is there any difference in the nutritional value of fertilised and unfertilised eggs?
\nHint:
\na. Layers are chickens raised for eggs and broilers are chickens raised for meat.
\nb. Yes, hens lay both the fertilised egg (if mating has occurred) and the unfertilised egg (according to light patterns if no mating has occurred).
\nc. Fertilised eggs are obtained by allowing hens to mate with roosters. Unfertilised eggs are obtained by exposing hens to suitable light patterns.
\nd. They are mostly unfertilised eggs.
\ne. Yes, fertilised eggs can be consumed.
\nf. No, there is no difference in the nutritional value of fertilised and unfertilised egg.<\/p>\n

Question 2.
\nObserve live Hydra yourself and learn how they reproduce by doing the following activity:
\nDuring 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.
\nHydra 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.
\nHint:
\nDo it yourself.<\/p>\n

\"NCERT<\/p>\n

Question 3.
\nThe 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.
\nHint:
\nDo it yourself.<\/p>\n

Question 4.
\nTalk 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.
\nHint:
\nTwins are identical when they are formed due to a random splitting in the developing embryo which then develops into two different individuals. Since they are formed from the same zygote, their sex is always the same. However, non-identical twins are formed by the fertilisation of two different egg cells.<\/p>\n

Activity 1<\/span><\/p>\n

Objective: To observe and study the eggs of frog.
\nProcedure: Visit some ponds or slow-flowing streams during spring or rainy season and observe the colour and size of frog\u2019s eggs floating on the water.
\nObservation: Amphibian eggs do not have a hard protective shell like the eggs of birds or reptiles. Frogs and toads lay eggs in jelly-like masses, and unless the eggs are covered with water, they will dry up and die.
\n\"NCERT<\/p>\n

Most amphibian eggs become much bigger after they are laid because the eggs absorb water and swell up to several times their original volume. The colour of the eggs is dull white and size ranges from less than a centimetre to a few centimetres.<\/p>\n

Asexual Reproduction: The type of reproduction in which only a single parent is involved is called asexual reproduction. It can be of the following major types:
\ni. Budding: This method is seen in multicellular organisms which are highly simple in structure. A small bud develops on the body. The bud grows and starts resembling its parent cell. After sufficient growth, the bud gets detached from the parent\u2019s body to begin life as a new individual. Examples: Hydra and sponges reproduce by budding.
\n\"NCERT<\/p>\n

Activity 2<\/span><\/p>\n

Objective: To study budding in Hydra with the help of permanent slide.
\nMaterials Required: Permanent slide of Hydra and a compound microscope.
\nProcedure:<\/p>\n