KSEEB Solutions For Class 8 Science Chapter 12 Reproduction In Animals

KSEEB Solutions For Class 8 Science Chapter 12 Reproduction In Animals Points To Remember

Reproduction: This is a process in which organisms produce young ones of their own kind.

There are two modes by which animals reproduce. These are;
1. Sexual reproduction, and
2. Asexual reproduction

Sexual Reproduction

Reproduction resulting from the fusion of male and female gametes is called sexual reproduction.

The reproductive organs in the female include ovaries, oviducts, and uterus.

The reproductive organs in males include the testes, sperm ducts, and penis.

The ovary produces female gametes called ova and the testes produce male gametes called sperms.

The fusion of the ovum and sperm is called fertilisation. The fertilized egg is called a zygote.

Fertilization that takes place inside the female body is called internal fertilization. This is observed in human beings and other animals such as hens, cows, and dogs.

Fertilization that takes place outside the female body is called external fertilization. This is observed in frogs, fish, starfish, etc.

The zygote divides repeatedly to give rise to an embryo.

The embryo gets embedded in the wall of the uterus for further development

The stage of the embryo in which all the body parts are identifiable is called the fetus.

Animals such as human beings, cows, and dogs that give birth to young ones are called viviparous animals.

Oviparous Animals: Animals that lay eggs are called oviparous animals, for example, frogs, lizards, butterflies, etc.

The transformation of the larva into an adult through drastic changes is called metamorphosis.

Asexual Reproduction

The type of reproduction in which only a single parent is involved is called asexual reproduction.

In hydra, new individuals develop from buds. This method of asexual reproduction is called budding.

Amoeba reproduces by dividing themselves into two. This type of asexual reproduction is called binary fission.

KSEEB Solutions For Class 8 Science Chapter 12 Reproduction In Animals

Kseeb Solutions For Class 8 Science Chapter 12 Reproduction In Animals Pdf

Reproduction In Animals NCERT Textbook Exercises

Question 1. Explain the importance of reproduction in organisms.
Answer: The production of new individuals from the parents is known as reproduction. Reproduction is very important as it ensures the continuation of similar kinds of individuals, generation after generation. If this process does not exist, the generation of living beings will vanish from the earth.

Question 2. Describe the process of fertilisation in human beings.
Answer:

In human beings, sexual reproduction occurs in which reproduction results from the fusion of male and female gametes.

Males produce sperm intestines and females produce ovum in the ovary.

Malerelease their sperms in the female reproductive organ during copulation called the vagina from where the sperms move towards the fallopian tube.

Females release one ovum every month in the middle of the menstruation cycle which travels toward the fallopian tube.

The fusion of male and female gametes takes place in the fallopian tube. The fusion of male and female gametes is called fertilisation.

Step-By-Step Solutions For Reproduction In Animals Class 8 Karnataka Board

Question 3. Choose the most appropriate answer.

Internal fertilisation occurs
1. In the female body.
2. Outside female body
3. In the male body
4. Outside male body

A tadpole develops into an adult frog through the process of
1. Fertilisation.
2. Metamorphosis
3. Embedding
4. Budding

The number of nuclei present in a zygote is
1. None
2. One
3. Two
4. Four

Answer:

Internal fertilisation occurs: 1. In the female body.

A tadpole develops into an adult frog by the process of 2. metamorphosis.

The number of nuclei present in a zygote is 2. One.

Karnataka Board Class 8 Science Chapter 12 Solutions

Question 4. Indicate whether the following statements are True or False

Oviparous animals give birth to young ones.
Each sperm is a single cell.
External fertilisation takes place in frogs.
The number of nuclei present in a zygote is
Egg laid after fertilisation is made up of a single cell.
Amoeba reproduces by budding.
Fertilisation is necessary even in asexual reproduction.
Binary fission is a method of asexual reproduction.
A zygote is formed as a result of fertilisation.
An embryo is made up of a single cell.

Answer: True/False

False
True
True
True
True
True
True
True
True
False

Question 5. Give two differences between a zygote and Foetus
Answer:

When fertilisation takes place, the nuclei of the sperm and the egg fuse to form a single nucleus, which results in the formation of a fertilized egg or zygote.

The zygote now begins to develop into an embryo.

The embryo continues to develop in the uterus and produces body parts such as hands, legs, head, eyes, etc the stage of the embryo in which all the body parts are identified is called a fetus.

Question 6. Define asexual reproduction. Describe two methods of asexual reproduction in animals.
Answer:

The type of reproduction in which only a single parent is involved is called asexual reproduction.

Asexual reproduction takes place in very small animals like Hydra and microscopic organisms like Amoeba.

Budding: New individual develops as outgrowths from a single parent. In hydra small bulges called buds develops into new individuals.

Binary fission: The body of unicellular organisms like amoeba divides into two equal parts and each part develops as a new individual.

Question 7. In which female reproductive organ does the embryo get embedded?
Answer: The embryo gets embedded in the wall of the uterus for further development.

Reproduction In Animals Class 8 Kseeb Solutions With Answers

Question 8. What is metamorphosis? Give examples.
Answer: The drastic change which takes place during the development of an animal is called metamorphosis The animals that undergo metamorphosis are
1. Silkworm (egg -> caterpillar-> pupa ->adult)
2. Frog (egg —> tadpole —> adult)

Question 9. Differentiate between internal fertilisation and external fertilisation.
Answer:

Internal fertilisation
1. fertilisation takes place inside the female body.
2. Example: human beings, hens, dogs,s, etc.

External fertilisation
1. The fertlilsatlon takes place outside the body of the female.
2. Example: frog, fish, etc.

Question 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 the hen.
7. 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 the fertilized egg.
4. These animals lay eggs
5. A type of fission in Amoeba

Reproduction In Animals Additional Questions

Question 1. What is a fertilised egg called?
Answer: Zygote

Question 2. Which mode of reproduction does take place in human beings?
Answer: Sexual reproduction

Question 3. Name two animals in which asexual reproduction takes place.
Answer: Hydra and yeast

Question 4. What is male gamete or sperm?
Answer: The reproductive cell produced by male reproductive organs is called the male gamete or sperm.

Question 5. What is a female gamete or ova?
Answer: The reproductive cell produced by female reproductive organs is called the female gamete or ova.

Question 6. Which organ produces eggs or the ovum?
Answer: A pair of ovaries.

Question 7. Which male reproductive organ produces sperm?
Answer: A pair of testes.

Question 8. In which organ fertillsation take place in female?
Answer: Fallopian tube

Question 9. What are the two methods of asexual reproduction?
Answer:

Budding
Binary fission

Question 10. Name two animals which undergo external fertilisation.
Answer: Frog and fish

Question 11. Name two animals which undergo internal fertilisation.
Answer: Human being and cow

Question 12. Which type of reproduction takes place in Amoeba?
Answer: Asexual reproduction through binary fission

Question 13. What type of reproduction is cloning?
Answer: Asexual reproduction

Question 14. What is a fetus?
Answer: Foetus is a well-developed embryo.

Kseeb Class 8 Science Reproduction In Animals Exercise Solutions

Question 15. How is an embryo developed?
Answer: Fertilisation results in the formation of a zygote. The zygote divides repeatedly to give rise to a ball of cells which then begin to form groups that develop into different tissues and organs of the body. This developing structure is called an embryo, It gets embedded in the wall of the uterus for further development.

Reproduction In Animals Class 8 KSEEB Questions And Answers

Question 16. What is cloning? Explain how the first cloned mammal was born.
Answer: Cloning is the production of an exact or a true copy of a cell, any other living part, or a complete organism by asexual reproduction, Cloning of an animal was successfully performed for the first time by Ian Wilmut and his colleagues at the Roslin Institute in Edinburgh, Scotland. They cloned the sheep named Dolly on July 5, 1996.
reproduction in animal sheeps

In the process of cloning Dolly, a cell was collected from the mammary gland of a female Finn Dorsett sheep. Meanwhile, an egg was obtained from a Scottish blackface ewe.

The nucleus was removed from the egg. Then the nucleus of the mammary gland cell from the Finn Dorsett sheep was inserted egg of the Scottish blackface ewe whose nucleus had been removed.

This egg was implanted into the Scottish blackface ewe. The egg developed normally and finally, Dolly was born.

The cloning of Dolly was a successful attempt. However, many clones often die soon after birth.

Sometimes cloning also leads to certain abnormalities among clones.

Unfortunately, Dolly died on 14th February 2003 due to a certain lung disease.

Question 17. What is budding? Explain.
Answer:

Budding is a type of asexual reproduction in which an organism or new individual develops from an outgrowth of a single parent. This outgrowth is called a bud.

On maturation, this bud gets separated from the parent’s body to grow into a new individual.

This process of reproduction is known as budding. For example, Hydra, yeast, and sponges produce their young ones through the process of budding.

In some organisms, like sponges, buds are not separated from their parent’s body and form a colony.

They remain attached to their parent’s bodies.

Question 18. Why do only male gametes have a tail?
Answer: Male gametes have to reach non-motile female gamete in the oviduct from the vagina. So they have a tail to reach the egg cell.

Reproduction In Animals Multiple Choice Questions

Question 19. Sets of reproductive terms are given below. Choose the set that has an incorrect combination.
1. Sperm, testis, sperm duct, penis
2. Menstruation, egg, oviduct, uterus
3. Sperm, oviduct, egg, uterus
4. Ovulation, egg, oviduct, uterus
Answer: 3. Sperm, oviduct, egg, uterus
Explanation: Sperm is the male gamete, the egg is the female gamete, oviduct, and uterus are part of the female reproductive system. Hence option 3. is an incorrect combination.

Question 20. In humans, the development of the fertilised egg takes place in the
1. Ovary
2. Testis
3. Oviduct
4. Uterus

Answer: 4. Uterus
Explanation: The development of the fertilised egg takes place in the uterus. Embryo gets embedded in the wall of the uterus for development by implantation.

Question 21. In the list of animals given below, the hen is the odd one out. a human being, cow, dog, and hen The reason for this is
1. It undergoes internal fertilisation.
2. It is oviparous.
3. It is viviparous.
4. It undergoes external fertilisation.

Answer: 2. It is oviparous
Explanation: The hen is oviparous, it lays the egg and the young one gets hatched later. The rest of the animals provided are viviparous. They give birth to young ones after they are developed completely.

Karnataka Board 8th Science Chapter 12 Important Questions And Answers

Question 22. Animals exhibiting external fertilisation produce a large number of gametes. Pick the appropriate reason from the following
1. The animals are small in size and want to produce more offsprings.
2. Food is available in plenty of water.
3. To ensure a better chance of fertilisation.
4. Water promotes the production of a large number of gametes.

Answer: 3. To ensure a better chance of fertilization
Explanation: Because they release gametes in water chances of getting washed away by water, wind and rain are more. Hence To ensure a better chance of fertilisation. A large number of gametes are produced by Animals exhibiting external fertilization.

Question 24. Reproduction by budding takes place in
1. Hydra
2. Amoeba
3. Paramecium
4. Bacteria

Answer: 1. Hydra
Explanation: Paramecium, Amoeba, and bacteria reproduce by binary fission. Hydra reproduces by budding where a bud detaches from the parent and grows into a complete organism.

Question 25. Which of the following statements about reproduction in humans is correct?
1. Fertilisation takes place externally.
2. Fertilisation takes place in the testes.
3. During fertilisation, the egg moves towards the sperm.
4. Fertilisation takes place in the human female.

Answer: 4. Fertilisation takes place in the human female.
Explanation: Male gametes are introduced into a female’s body through the vagina. Sperm reaches the uterus through the oviduct. At the uterus, the egg gets fertilized by sperm to form a zygote.

Question 26. In human beings, after fertilisation, the structure which gets embedded in the wall of the uterus is
1. Ovum
2. Embryo
3. Foetus
4. Zygote

Answer: 2. Embryo
Explanation: The egg fuses with sperm to form the zygote which will divide to form a clump of hundreds of cells that form the embryo. The process of moving down embryo from the oviduct into the uterus is called as implantation.

Explanation Of Reproduction In Animals In KSEEB Science

Question 27. Aquatic animals in which fertilisation occurs in water are said to be:
1. Viviparous without fertilisation.
2. Oviparous with external fertilisation.
3. Viviparous with internal fertilisation.
4. Oviparous with internal fertilisation.

Answer: 2. Oviparous with external fertilisation.
Explanation: Aquatic animals lay eggs and release sperm into the water for fertilization to take place. Young one is formed outside the body hence it is called external fertilization.

Kseeb Class 8 Science Chapter 12 Textbook Solutions

Question 28. After fertilisation, the resulting cell which gives rise to a new individual is the
1. Embryo
2. Ovum
3. Foetus
4. Zygote
Answer: 4. Zygote
Explanation: The zygote is the beginning of the formation of a new individual. All multicellular organisms start their life from the single-celled zygote.

Question 29. In human beings, the correct sequence of events during reproduction is
1. Gamete formation, fertilisation, zygote, embryo
2. Embryo, zygote, fertilisation, gamete formation
3. Fertilisation, gamete formation, embryo, the zygote
4. Gamete formation, fertilisation, embryo, the zygote
Answer: 1. Gamete formation, fertilisation, zygote, embryo
Explanation: In humans, male gametes fuse with female gametes to fertilise in the female ovary. Fertilised sperm and egg form zygote which will divide repeatedly to form the embryo.

Question 30. Although 2 cells called gametes fuse, the product formed is a single cell called the zygote. Justify.
Answer: During fertilization, only the nucleus ofthe sperm gets implanted into the uterus to forma zygote. Then sperm degenerates. Hence fused cell is called gamete. Stages in the lifecycle of silkwormare given below. Write them in sequential order.

Question 31. Stages in the lifecycle of silkworms are given below. Write them in sequential order. pupa, silkworm, egg, silkmoth
Answer:
1. Egg.
2. Pupa.
3. Silkmoth.
4. Silkworm.

Question 32. What is the importance of reproduction?
Answer: Reproduction ensures the continuation of species from generation to generation.

Question 33. In markets, eggs of birds are available but never eggs of dogs. Why?
Answer: Because the dog is viviparous. It does not lay an egg. It gives birth to a new one.

Question 34. The eggs of frogs do not have shells for protection, yet they are safe in the water. How?
Answer: Jelly-like covering on the eggs gives protection Hence frog eggs are safe in the water.

Question 35. The term metamorphosis is not used while describing human development. Why?
Answer: Because body parts of humans will be present by birth. Whereas in metamorphosis parts of adults are different from the young ones.

Kseeb 8th Standard Science Chapter 12 Notes And Solutions

Question 36. Mother gives birth to a baby but the baby has characteristics of both parents. How is this possible?
Answer: Though the mother gives birth to the baby fertilization involves the fusion of gametes from both parents. Hence character is obtained by both parents.

Question 37. How is reproduction in hydra different from that in amoeba?
Answer: Hydra reproduces by budding where a bud detaches from the parent which grows into a complete organism. Whereas amoeba reproduces by binary fission. The process of reproduction begins with the division of its nucleus into two. This is followed by the division of its body into two.

Question 38. State whether the following statements are True or False. If false, correct the statement:
1. External fertilisation can occur both in water and on land.
2. The eggs of fish are covered by hard shells for protection.
3. The human egg has a head, middle piece and tail.
4. In adult human females, a single mature egg is released into an oviduct every month.

Answer:
1. False: External fertilisation can occur only in water.
2. False: eggs of fish are covered by jelly-like substance for protection.
3. False: Human sperm has a head, middle piece and tail.
4. True

Question 39. Why do only male gametes have a tail?
Answer: Because sperm need to be motile to reach the non-motile egg in the ovary of the female.

KSEEB Solutions For Class 8 Science Chapter 12 Reproduction In Animals