Reproduction in Animals Class 8 Extra Questions and Answers

These AP 8th Class Biology Important Questions and 4th Lesson Reproduction in Animals Class 8 Extra Questions will help students prepare well for the exams.

Class 8 Science Reproduction in Animals Extra Questions

Reproduction in Animals Class 8 Important Questions

Question 1.
What is meant by external fertilization ?
Answer:
The process of fertilization that occurs outside of an organism is called External Fertilization.
E.g.: Frog, Fish, Star fish etc.

Question 2.
What is meant by internal Fertilization ?
Answer:
The process of fertilization that takes place inside the body of females is called Internal Fertilization. E.g.: Animals, Human beings.

Question 3.
Which are called viviparous animals ?
Answer:
Animals which give birth to their offsprings are called Viviparous animals.
E.g.: Animals, Hiiman beings.

Question 4.
What are oviparous animals ?
Answer:
Animals which lay eggs are called oviparous animals.
E.g. Hen, Duck, Pigeon etc.

Question 5.
Which is formed by the fusion of maid and female gametes ?
Answer:
Zygote is formed by the fusion of’male and female gametes.

Question 6.
Which gamete is that has a tail and travel to fuse with female gamete ?
Answer:
Male gamete or sperm or spermatozoa. The structure of sperm has a head, a middle piece and a tail.

Question 7.
What are different modes of reproduction in animals ?
Answer:
There are two different types of reproduction in animals.
They are

1. Sexual reproduction and
2. Asexual reproduction.

Question 8.
What are the male reproductive organs in humans ?
Answer:
The male reproductive organs are a pair of tastes, sperm ducts and penis.

Question 9.
What are the female reproductive organs in humans ?
Answer:
The female reproductive organs of humans are a pair of ovaries, oviducts (fallopian tubes) and the uterus.

Question 10.
What does ovary produce ?
Answer:
Ovary produces female gametes called Ova (or) Egg.

Question 11.
Expand IVF.
Answer:
IVF : In Vitro Fertilisation.

Question 12.
What is the larva of frog ?
Answer:
Tadpole larva.

Question 13.
What is an embryo ?
Answer:
The zygote undergoes repeated cell divisions and form groups of tissues and organs of the body. This developing structure is called an embryo.

Question 14.
What is foetus ?
Answer:
The stage of the embryo in which all the body parts can be identified is called a foetus.

Question 15.
What is the larva of butterfly ?
Answer:
Caterpillar larva.

Question 16.
What is metamorphosis ?
Answer:
The transformation of the larva into an adult through drastic changes is called metamorphosis.

Question 17.
What is budding ?
Answer:
New individuals develop from the buds in hydra, this type of asexual reproduction is called budding.

Question 18.
How many daughter amoeba are formed at the end of the binary fission ?
Answer:
Two daughter amoeba are formed.

Question 19.
What is binary fission ?
Answer:
The mode asexual reproduction in which an animal reproduces by dividing into tw,o individuals is called binary fission.

Question 20.
How are chicks born in hens ?
Answer:
Chicks are not actually born, they are hatched from eggs. A hen will ovulate and lay egg within 24 hours. It takes about 3 weeks for them to hatch.

Question 21.
How are the eggs of frogs are protected in water even though they have no shells ?
Answer:
A layer of jelly covers the eggs of the frog and provides protection.

Question 22.
What happens just before the following stages ?
a) Formation of embryo
Answer:

1. The first step in the process of reproduction is the fusion of a sperm and an ovum.
2. When sperms come in contact with an egg one of the sperms may fuse with the egg.
3. Such fusion of the egg and the sperm is called fertilization. During the fertilization, the nuclei of the sperm and the egg fuse to form a single nucleus called zygote.
4. The zygote divides repeatedly to give rise to a ball of cells. These cells begin to form groups that develop into different tissues and organs of the body.
5. This developing structure is termed as an embryo.

b) Development of embryo
Answer:

1. The embryo gets embeded in the wall of the uterus for further development.
2. The embryo continues to develop in the uterus. It gradually develops body parts such as hands, legs, head, eyes, ears etc.
3. The state of embryo in which all the body parts can be identified is called a foetus.
4. When the development of the foetus is complete, the mother gives birth to the baby.

Reproduction in Animals Extra Questions

Question 1.
Differentiate between sexual reproduction and asexual reproduction.
Answer:

Sexual Reproduction	Asexual Reproduction
1. Male and female gametes are formed.	1. No production of gametes.
2. Involves fusion of male and female gametes.	2. No fusion of gametes.
3. Involves two organisms.	3. Involves a single organism.
4. Offsprings have some characters from male parent and other from female parent, feome characters may not be present in either of the parents.	4. Produces offsprings that are identical to the parent.

Question 2.
Complete this flow chart.

Answer:
1 – Testes
2 – Sperms
3 – Ovary
4 – Ovum
5 – Embryo
6 – Foetus

Question 3.
What is meant by cloning ? Who invented this ?
Answer:

1. Cloning is the reproduction of an exact copy of the cell any other living part or complete organism from somatic cells.
2. Cloning of an animal was successfully performed for the first time by Ian Wilmut in Scotland.

Question 4.
If you want to clarify some doubts about test tube babies what questions do you ask a doctor ?
Answer:

1. Who are test tube babies ? Why are they called so ?
2. What differences may we find between normally born babies and a test tube baby ?
3. What problems will test tube babies face in their life ?
4. Why people believe rumours about test tube babies ?

Question 5.
Draw and label the structure of Human Ovum.
Answer:

Question 6.
Draw a neat diagram showing the process of fertilisation.
Answer:

Question 7.
Draw a neat and labelled diagram of zygote.
Answer:

Question 8.
Draw a neat and labelled diagram showing foetus in the Uterus.
Answer:

Question 9.
Draw a neat diagram, showing budding in hydra.
Answer:

Question 10.
Draw a neat diagram showing binary fission in amoeba.
Answer:

Question 11.
Write a short note on human sperm.
Answer:

1. Sperms are male gametes produced in millions by testes.
2. Though they are small in size, each has a head, a middle peice and a tail.
3. Each sperm is a single cell with all the usual cell components.
4. The tail of sperm is useful in motility to reach the ovum in oviduct. Then, fertilisation takes place.

Extra Questions of Reproduction in Animals Class 8

Question 1.
How are test tube babies born ?
Answer:

1. In some women oviducts are blocked. So, these women are unable to bear babies because sperms can not reach the egg for fertilisation.
2. In such cases, doctors collect freshly released egg and sperms and keep them together for a few hours for IVF (In Vitro Fertilisation means fertilisation outside the body of women)
3. The fertilised zygote is allowed to develop for about a week and then it is placed in the mother’s uterus.
4. Complete development takes place in the uterus of mother and baby is born like any other baby.
5. Babies born through this method are called test tube babies.

Question 2.
Write a detailed note on cloning.
Answer:

• Besides Asexual and Sexual Reprodution, there is other mode of reproduction called cloning.
• Cloning is the production of an exact copy of a cell, any other living part, or a complete organism.
• 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 successfully cloned a sheep named Dolly. Dolly was born on 5th July 1996 and was the first mammal to be cloned.
• During the process of cloning dolly, a cell was collected from the mammary gland of a female Finn Dorset Sheep.

• Simultaneously, an egg was obtained from Scottish black face ewe.
• The nucleus was removed from the egg. Then the nucleus of the mammary gland cell A) Finn Dorset B) Scottish C) Dolly from the Finn Dorset sheep was inserted sheep Black face into the egg of the Scottish black face ewe – ewe whose nucleus had been removed.
• Thus the egg produced was implanted into the Scottish black face ewe. Development of this egg followed normally and finally Dolly was born.
• Though Dolly was given birth by the Scottish black face ewe, it was found to be absolutely identified to the Finn Dorset sheep, from which the nucleus was taken.
• Since the nucleus from the egg of the Scottish black face ewe was removed, Dolly did not sho\y any character of the Scottish black face ewe.
  Dolly was a healthy clone of the Finn Dorset sheep and produced several off¬springs of her own through normal sexual means.

Question 3.
What would happen if all the organisms stop the process of reproduction ?
Answer:

1. Without reproduction living organisms would not survive long.
2. Different species of living organisms die due to various reasons.
   E.g. Old age, diseases, accidents, etc.
3. Imagine the death of members of a species continues and new individuals of that species are not added.
4. A stage will come when that species will disappear.
5. To ensure the continuity of the species reproduction is important.
6. Depending on the available conditions in a community, different species will reproduce continuously and increase their numbers.
7. Reproduction in a species will therefore:
   a) Replace those species that die and
   b) Allow an increase in total numbers of the species under suitable conditions.

Question 4.
Draw a neat and labelled diagram of male reproductive system in humans.
Answer:

Question 5.
Draw a neat and labelled diagram of female reproductive system in humans.
Answer:

Question 6.
Draw a neat and labelled diagram of zygote formation and development of an embryo from the zygote.
Answer:

Question 7.
Draw a neat and labelled diagram of life cycle of frog.
Answer:

Question 8.
Write the differences you observed in the reproduction of amoeba and frog.
Answer:

Reproduction in Amoeba	Reproduction in Frog
1. Reproduces asexually through binary fission.	1. Reproduces sexually.
2. Fusion of gametes will not occur.	2. Fusion of gametes, takes place.
3. Only two daughter amoebas are formed.	3. Through external fertilisation many off springs will take birth in water.
4. Daughter amoebas completely resemble parent amoeba	4. Offsprings horned exhibit variations.
5. Mother amoeba will extinct after binary fission	5. Mother frog will not extinct after external fertilisation.

Question 9.

Now observe the above diagram and answer the following questions.
1) Name the reproductive system shown in the above picture.
2) What are the labelled parts A, B. C ?
3) Which of the above organ produces sperm cells ?
4) What is the function of Part – A ?
Answer:
1) Human male reproductive system.
2) A – Sperm ducts
B – Testes
C – Penis
3) Testes produce sperm cells.
4) This ducts connects each testis to the urethra they transport sperms into the penis.

Question 10.

Observe the above reproductive system and answer the questions.
1) Name the reproductive system shown in the above diagram.
2) Name the labelled parts A, B. C in the above diagram.
3) Where does fertilisation take place ?
4) Where does the fertilised zygote develop ?
Answer:
1. Female reproductive system in humans.
2. A – Oviduct
B – Ovary
C – Uterus
3. In Oviduct
4. In Uterus.

Question 11.
How do you differentiate between egg ova and sperm?
Answer:

Sperm (Male gamete)	Ova or egg (Female gamete)
1) These are produced in male organisms.	1) These are produced in female organism.
2) Each sperm has a head, middle piece and tail.	2) It is round in shape.
3) These are produced in millions.	3) These are produced single every month.
4) These are motile.	4) These are non-motile.
5) Life span is 24 to 72 hours.	5) Life span is 25 hours.
6) Sperm is smaller in size.	6) Ovum is larger in size.

Question 12.
Describe the development of Embryo into the baby.
Answer:

1. Fertilization results in the formation of zygote which begins to develop into an embryo.
2. The zygote divide repeatedly to give rise to a ball of cells. The cells then begin to form groups that develop into different tissues and organs of the body.
3. This developing structure is termed as Embryo. The embryo gets embedded in the wall of the uterus for further development.
4. The embryo continues to develop in the uterus. It gradually develop body parts such as hands, legs, head, eyes, ears, etc.
5. The stage of embryo in which all the body parts can be identified is called a Foetus.
6. When the development of the foetus is complete, the mother.gives birth to a baby.