Chapter 14 : Reproduction in Animals
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1. Genetically identical individuals are produced by
________ reproduction.
ANS: asexual
2. ________ are the specialised cells that take part
in sexual reproduction.
ANS: Gametes
3. An animal, that produces both male and female
gametes, is known as a ________ animal.
ANS:
hermaphrodite
4. A fertilised egg is also known as the ________.
ANS: zygote
5. The incubation period for a hen’s egg is ________.
ANS: 21 days
|
Column A |
Column B |
|
1. Hydra |
(c) budding |
|
2. Reptiles |
(d) oviparous |
|
3. Earthworm |
(a) hermaphrodite |
|
4. Gills |
(e) tadpole |
|
5. Egg shell |
(b) calcite |
1. The site of fertilisation, in humans, is the—
•
uterus
•
oviduct
•
vagina
•
ovary
ANS: oviduct
2. The reason, why parrot does not belong to the same
group as that of monkey, man, cat, is that—
•
it is
oviparous.
•
it undergoes
external fertilisation.
•
it undergoes
internal fertilisation.
•
it is
viviparous.
ANS: it is oviparous.
3. An organism, which reproduces by Budding, is—
•
Plasmodium
•
Amoeba
•
Yeast
•
Spirogyra
ANS: Yeast
4. A caterpillar develops into a silk moth through the
process of—
•
fertilisation
•
metamorphosis
•
hatching
•
parthenogenesis
ANS: metamorphosis
5. A foetus can be best defined as—
•
a fertilised
egg.
•
a developing
embryo.
•
a well
developed embryo.
•
an
unfertilised egg.
ANS: a well developed embryo.
1. Distinguish between asexual and sexual
reproduction.
ANS:
(a) Asexual reproduction involves only one parent, whereas sexual reproduction generally involves two parents.
(b) In asexual reproduction, fusion of gametes does not occur, whereas in sexual reproduction male and female gametes fuse together.
(c) Young ones formed by asexual reproduction are genetically identical to the parent, whereas in sexual reproduction they are not identical to the parents.
2. How is reproduction carried out in Hydra?
ANS:
Reproduction in Hydra takes place by budding. A small outgrowth called a bud develops on the body of Hydra. The bud gradually grows in size and finally separates from the parent body to live independently.
3. How is fertilisation in a hen different from
fertilisation in a frog?
ANS:
(a) In a hen, fertilisation is internal and occurs inside the body of the female.
(b) In a frog, fertilisation is external and takes place outside the body in water.
4. State the difference between oviparous and
viviparous animals.
ANS:
(a) Oviparous animals lay eggs, whereas viviparous animals give birth to young ones.
(b) In oviparous animals, development occurs outside the mother’s body, whereas in viviparous animals development occurs inside the mother’s body.
5. Why is the number of eggs, laid by frogs at a time,
much higher than those laid by a hen?
ANS:
In frogs, fertilisation and development take place externally in water. Many eggs are destroyed by predators and environmental conditions. Therefore, frogs lay a large number of eggs to ensure survival of some young ones.
6. How will you differentiate between a zygote and an
embryo?
ANS:
(a) A zygote is the fertilised egg formed after fusion of male and female gametes, whereas an embryo is the developing stage formed after repeated divisions of the zygote.
(b) A zygote is a single cell, whereas an embryo consists of many cells.
7. It is the mother who gives birth to a child. How do
children, then, get features of both the parents?
ANS:
Children get features of both parents because the zygote is formed by fusion of the sperm from the father and the ovum from the mother. Thus, the child inherits characteristics from both parents.
1. Define the term ‘Metamorphosis’.
List the changes that a tadpole undergoes to develop into a frog.
ANS:
Metamorphosis is the marked and abrupt change in the
structure and habits of an animal during its life cycle.
The changes in a tadpole during metamorphosis are:
(a) Hind legs develop first.
(b) Front legs appear later.
(c) Lungs develop and gills disappear.
(d) The tail gradually shortens and is absorbed.
(e) The tadpole changes into an adult frog.
2. Trace the sequence of events that lead to
development of a chick from the fertilised egg of a hen.
ANS:
(a) Fertilisation takes place inside the body of the
hen.
(b) The zygote moves down the oviduct.
(c) Protective layers and shell are formed around the
egg.
(d) The egg is laid outside the body.
(e) The embryo develops inside the egg during the
incubation period of about 21 days.
(f) The shell breaks and the chick comes out. This
process is called hatching.
3. Where does fertilisation occur in human beings? How
does the zygote formed eventually develop into an infant?
ANS:
Fertilisation in human beings occurs in the oviduct of
the female reproductive system. The zygote undergoes repeated cell divisions
and forms an embryo. The embryo gets implanted in the uterus and continues to
develop. When body parts become identifiable, it is called a foetus. After
complete development, the baby is born as an infant.
4. Draw a neat and well labelled diagram of the human
sperm. Also, write how its shape and size help it in its functioning?
ANS:
The human sperm consists of three parts — head, middle
piece and tail. The head contains the nucleus and enzymes that help the sperm
penetrate the ovum. The middle piece provides energy for movement. The tail
helps the sperm to swim towards the egg. The sperm is very small and
streamlined, which helps it move easily.
5. Draw a neat and well labelled diagram of (i) the
reproductive system of the human female (ii) the male reproductive system.
ANS:
(a) In the female reproductive system, label the
ovaries, oviducts, uterus and vagina.
(b) In the male reproductive system, label the testes,
sperm ducts, urethra and penis.
6. Write the function(s) of each of the following
parts of the human female reproductive system:
(a) Ovaries
ANS: Ovaries produce ova (eggs) and female hormones.
(b) Oviduct
ANS: Oviduct carries the ovum to the uterus and is
also the site of fertilisation.
(c) Uterus
ANS: Uterus is the site where the embryo gets
implanted and develops into a foetus.
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