Lesson: Reproduction in Animals
MULTIPLE CHOICE QUESTIONS
Sets of reproductive terms are given below.
Choose the set that has an incorrect combination.
(a) Sperm, testis, sperm duct, penis
(b) Menstruation, egg, oviduct, uterus
(c) Sperm, oviduct, egg, uterus
(d) Ovulation, egg, oviduct, uterus
In humans, the development of fertilised egg takes place in the:
In the list of animals given below, hen is the odd one out.
Human being, cow, dog, hen
The reason for this is:
(a) It undergoes internal fertilisation.
(b) It is oviparous.
(c) It is viviparous.
(d) It undergoes external fertilisation.
Animals exhibiting external fertilisation produce large number of gametes.
Pick the appropriate reason from the following:
(a) The animals are small in size and want to produce more offspring.
(b) Food is available in plenty in water.
(c) To ensure better chances of fertilisation.
(d) Water promotes production of large number of gametes.
Reproduction by budding takes place in
Which of the following statements about reproduction in humans is correct?
(a) Fertilisation takes place externally.
(b) Fertilisation takes place in the testes.
(c) During fertilisation egg moves towards the sperm.
(d) Fertilisation takes place in the human female.
In human beings, after fertilisation, the structure which gets embedded in the wall of uterus is
Aquatic animals in which fertilisation occur in water are said to be:
(a) Viviparous without fertilisation.
(b) Oviparous with external fertilisation.
(c) Viviparous with internal fertilisation.
(d) Oviparous with internal fertilisation.
After fertilisation, the resulting cell which gives rise to a new individual is the:
In human beings, the correct sequence of events during reproduction is
(a) Gamete formation, fertilisation, zygote, embryo
(b) Embryo, zygote, fertilisation, gamete formation
(c) Fertilisation, gamete formation, embryo, zygote
(d) Gamete formation, fertilisation, embryo, zygote
VERY SHORT ANSWER QUESTIONS (5)
Although 2 cells called gametes fuse, the product formed is a single cell called zygote. Justify.
During fertilisation, the nucleus of the sperm and the egg fuse to form a single nucleus. This results in the formation of zygote, which is the fertilized egg.
Stages in the lifecycle of silkworm are given below.
Write them in sequential order. Pupa, caterpillar, egg, silk moth
Egg, caterpillar, pupa, silk moth
What is the importance of reproduction?
Reproduction ensures the continuous generation of species by helping organism to produce their offspring.
In markets, eggs of birds are available but never eggs of dogs.
Dogs are viviparous so they cannot lay eggs.
The eggs of frogs do not have shells for protection, yet they are safe in water. How?
The eggs of frogs are covered by a layer of jelly which provides protection from the surrounding water.
SHORT ANSWER QUESTIONS (8)
Fill up the blanks with the terms given below:
Body, asexual, binary, single, nucleus
Amoeba is a ___________ celled organism. It reproduces by___________ reproduction. The process of reproduction begins by the division of its ___________ into two. This is followed by the division of its ___________ into two. This type of reproduction is called ___________ fission.
Single, asexual, nucleus, body, binary
The term metamorphosis is not used while describing human development. Why?
In metamorphosis, the body parts of the adult are different from those at the time of birth. This is not true for human beings. In human beings, body parts of an adult are present from the time of birth which only grow and develop in size with no complete changes in structure. Hence, we cannot use the term metamorphosis while describing human development.
Mother gives birth to a baby but the baby has characters of both parents.
How is this possible?
The fertilisation process involves two gametes, one from the mother and the other from the father. Therefore, the zygote has both the father’s and mother’s contributions. Hence, the baby has characteristics of both the parents.
How is reproduction in hydra different from that in amoeba?
Hydra reproduces by budding, in which an outgrowth arises from the parent and develops into a new individual. Whereas, an amoeba reproduces by binary fission, in which the parent cell is divided to form two new cells.
State whether the following statements are True or False.
If false, correct the statement:
(a) External fertilisation can occur both in water and on land.
(b) The eggs of fish are covered by hard shells for protection.
(c) Human egg has a head, middle piece and tail.
(d) In adult human females, a single mature egg is released into an oviduct every month.
(a) False. External fertilization can occur only in water.
(b) False. The eggs of fish are covered by jelly for protection.
(c) False. Human sperm has a head, a middle piece and a tail.
Why do only male gametes have a tail?
Male gametes have to be motile and reach the non-motile female gametes during fertilization. Hence, the male gametes have a tail.
What does the given figure represent?
The figure represents an amoeba undergoing binary fission with a dividing nucleus.
Observe the figure given and answer the questions that follow.
(a) Label A and B.
(b) Identify the process.
(c) What happens during this process and what is formed?
(a) A-sperm; B-ovum (egg)
(c) The nucleus of the sperm fuses with the nucleus of the egg to form the zygote.
LONG ANSWER QUESTIONS (4)
How can we say that fish exhibits external fertilisation?
Female fish releases eggs into water and male fish releases sperms into water. Sperms swim randomly and come in contact with the eggs. The nucleus of the sperm then moves into the egg, and fuses with it, causing fertilisation. Since fertilisation occurs outside the female fish’s body in water, it is called external fertilisation.
After observing the figure, answer the following:
a. Read the following statements and label them in the figure:
(i) The part which produces female gametes.
(ii) The part where development of the baby takes place.
(iii) The part through which the developing embryo passes to reach the uterus.
b. Explain the future development of the embryo that would take place after it gets embedded in the uterus.
a. (i) Ovary
(iii) Oviduct or fallopian tube
b. After the embryo gets embedded in the wall of the uterus, it develops body parts such as head, eyes, hands, legs, etc. The stage of the embryo in which all the body parts can be identified is called foetus. When the development of the foetus is complete, the mother gives birth to the baby.
Hens and frogs are both oviparous exhibiting different types of fertilisation. Explain.
Both hens and frogs produce eggs. But the difference lies where the fertilization occurs. In frogs, the fertilised egg develops into an embryo inside the body, whereas, the fertilization of hen’s egg takes place outside the body.
Observe the following figures:
(1). Identify the stages in figure during development of human baby.
(2). Arrange the stages in correct sequence of development.
(3). Explain the development that takes place in any one stage.
1 (a) Embedding of the embryo in the uterus
(c) Zygote formation and development of an embryo from the zygote
(d) Fusion of nuclei in the zygote
2 The correct sequence is c, b, d, a.
3 Zygote formation: The sperm and the egg nuclei fuse to form a single nucleus, which results in the formation of a fertilized egg called zygote.