Worksheet solutions for chapter: Reproduction in Animals for class 8 are provided below.
(1) Define reproduction? Name the male and female reproductive parts of the human.
Reproduction is a process in which male and female adults produce similar young ones.
Eg:- Human produces babies who looks like humans.
The male reproductive organs are two testes, two sperm ducts and a penis. The female reproductive parts are a pair of ovaries, oviducts (Fallopian tubes) and the uterus.
(2) What is test tube baby? Explain how they born.
When oviducts of some women blocked or male have less sperm count, sperm can not reach to egg for fertilisation. In these conditions doctors collect freshly released egg and sperm and keep them together for fusion (IVF). After fertilisation zygote is allowed to develop for a week. Then it is placed in mother’s uterus where zygote develop completely and a baby born.
The baby who is born with in vitro fertilisation is called test tube baby. The baby is called test tube baby because fusion takes place out side female body but zygote develops inside the body.
(3)Why aquatic animals lay hundreds of egg and release millions of sperm?
Aquatic animals lay hundreds of egg and release millions of sperm because of reasons given below:-
(i) Eggs and sperms get exposed to water movement.
(ii) Some times, eggs and sperms destroyed by the wind and rainfall.
(iii) Sometimes, eggs are eaten by the other animals of the pond.
All these reasons also support production of eggs and sperms in large number.
(4)Write down differences between viviparous animals and oviparous animals.
The differences between viviparous animals and oviparous animals are tabulated below:-
|S N||Viviparous Animals||Oviparous animals|
|1.||These animals give birth to young ones.||These animals lay egg.|
|2.||The internal fertilisation takes place in these animals.||The external fertilisation takes place in these animals.|
|3.||Eg:- Human, cow etc.||Eg:- fish, frog , hen etc.|
(5)Write down differences between sexual and asexual reproduction.
The differences between sexual and asexual reproduction are tabulated below:-
|SN||Sexual Reproduction||Asexual Reproduction|
|1.||Both parents (Male and female) are required for sexual reproduction.||Reproduction is completed by single parent.|
|2.||Male and female gametes are fussed to form zygote which develops into a new individual.||The new individual is born or develops from the out growth due to cell division.|
|3.||Eg:- Human, cow etc.||Eg:- Hydra, yeast, amoeba etc.|
(6) Match the items of group A to the items of group B.
Group A Group B
(i) Cloning Fish
(ii) IVF Ovary
(iii) Zygote Dolly
(iv) Female reproductive part Test tube baby
Group A Group B
(i) Cloning Fertilised egg (iii)
(ii) IVF Ovary (iv)
(iii) Zygote Dolly (i)
(iv) Female reproductive part Test tube baby (ii)
(7) Write a short note on the cloning of a sheep “Dolly”.
Cloning is a process in which clone of a cell or a complete organism is copied exactly.
It was first done by Ian Wilmut and his colleagues at the Roslin Institute in Edinburgh.They successfully cloned a sheep on 5 July 1966.
They collected a cell from a female of Finn Dorsett sheep. They also take an egg from a Scottish blackface ewe. The nucleus of the egg was removed. The nucleus of the Finn Dorsett sheep is transferred in to the egg of the Blackface ewe. After the development of the egg the sheep had born which is named “Dolly” which shows resemblance and characteristics of the Finn Dorsett Sheep whose nucleus was used in the development of the dolly.
(8) Give differences between embryo and foetus.
Differences between embryo and foetus are tabulated below:-
|1.||Embryo is a developed zygote.||It is a developed embryo.|
|2.||Different tissues and organs begin to develop.||All the body parts can be identified.|
|3.||Embryo turns in to foetus.||It is trun in to baby.|
(9) What is sperm and what purpose does the tail in a sperm serve?
The sperm is a single celled male gametes which is produced by the testes in millions.
It is very small in size. They have head, middle piece and a tail. The tail is very helpful in the movement.
(10) How a chick develops from an egg laid by mother hen?
After the fertilisation in the oviparous animals the zygote divides repeatedly and travels down the oviduct with many protective layers. When zygote has a hard shell like protective layer the egg came out from the oviparous animals. The embryo of egg develops inside the egg shell. The embryo of a hen takes about 3 weeks to develop into a chick. The hen sits on the egg to provide warmth to the egg. When the development of the chick takes place inside the egg shell the chick bursts open the egg shell.