Question1: Explain
the importance of reproduction in organisms.
Answer:
1. Reproduction is essential for the continuation of a
species.
2. It ensures the continuation of similar kinds of
individuals, generation after generation.
Question2: Describe
the the process of fertilization in human beings.
Answer: There is sexual
reproduction in human beings. Male reproductive organs produce sperms (male gametes)
while the female gametes produce ova (female gametes). The sperms are ejected inside female bodies
where they fuse with ovum and forms zygote (called internal fertilization). The
single celled zygote begins to develop into an embryo which attaches to the
female uterus wall. The embryo further multiples into many cells and develops
further into a small baby called foetus.
Question3: Choose
the most appropriate answer:
(a) Internal fertilization occurs (i) in female body. (ii)
outside female body. (iii) in male body. (iv) outside male body.
Answer: (i) in female body.
(b) A tadpole develops into an adult frog by the process of
(i) fertilization. (ii) metamorphosis. (iii) embedding. (iv) budding.
Answer: (ii) metamorphosis.
(c) The number of nuclei present in a zygote is (i) none.
(ii) one. (iii) two. (iv) four.
Answer: (iii) two (fused
nuclei).
Question4: Indicate
whether the following statements are True (T) or False (F):
(a) Oviparous animals give birth to young ones.(F)
(b) Each sperm is a single cell. (T)
(c) External fertilization takes place in frog.(T)
(d) A new human individual develops from a cell called
gamete.(F)
(e) Egg laid after fertilization is made up of a single cell.(T)
(f) Amoeba reproduces by budding.(F)
(g) Fertilization is necessary even in asexual reproduction.(F)
(h) Binary fission is a method of asexual reproduction.(T)
(i) A zygote is formed as a result of fertilization.(T)
(j) An embryo is made up of a single cell.(F)
Question5: Give
two difference between a zygote and a foetus.
Answer:
ZYGOTE
|
FOETUS.
|
1)The
product of fusion of the nuclei of the sperm and egg is called zygote.
|
1)The stage
of the embryo which nearly resembles a human being is called a foetus.
|
2)It is a
unicellular structure. i.e single cell containing diploid(43 chromosomes)in
nucleus.
|
2)It is a
multicellular structure
|
Question6: Define
asexual reproduction. Describe two methods of asexual reproduction in animals.
Answer:Asexual reproduction is a
mode of reproduction in which only one parent is involved to reproduce
offspring. In asexual reproduction, the offsprings produced are exact copies of
their parents.
It is generally observed in very small sized organisms.
Binary fission, Budding, Fragmentation etc. are the examples of asexual
reproduction.
1. Budding: In this
mode, a part of the organism starts bulging out. Slowly it grows and develops
into a separate individual. Examples: Hydra, yeast.
2. Binary Fission: It
is a type of asexual reproduction in which a single cell divides into two
halves. Organisms that reproduce through binary fission are bacteria and
Amoeba.
Question7: In
which female reproductive organ does the embryo get embedded?
Answer:In walls of the uterus.
The embryo, once attached to uterus gradually develops various body parts such
as hands, legs, head, eyes, etc into an embryo.
Question8: What
is metamorphosis? Give examples.
Answer:Metamorphosis is a
biological process in which a larva transforms into an adult. It involves
sudden and abrupt changes in the body structure of the animal by cell growth
and differentiation. it is generally observed in amphibians (e.g. frogs) and
insects (e.g. butterflies) etc.
The life cycle of a frog has three life stages.
Egg >>>>> Tadpole >>>> Adult
1. Eggs: Eggs are the result of external fertilization which
transform into fish like tadpoles.
2. Tadpoles: Tadpole has gills, small mouth and fish like
tail to swim inside lakes and ponds.
3. Frog: Tadpoles grows and transform into a small frog
which is amphibian by nature.
Question9: Differentiate
between internal fertilization and external fertilization.
Answer:
INTERNAL
FERTILIZATION
|
EXTERNAL
FERTILIZATION
|
Fusion of male and
female gametes inside female body.
|
Fusion of male and
female gametes outside female body.
|
High chances of
survival of offspring, so less number of ova/eggs are produced.
|
Low chances of
survival, large number of eggs are produced
|
Cows, Hens, Human
beings (mostly mammals).
|
Examples: Fish, frog,
starfish
|
Question10: Complete
the cross-word puzzle using the hints given below
Across
1. The process of the fusion of the gametes.
6. The type of fertilization in hen.
7. The 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.
Answer:
1- FERTILIZATION
2- TESTIS
3- ZYGOTE
4- OVIPAROUS
5- BINARY
6- INTERNAL
7- BUDS
8- OVARY
Chapter 9 Reproduction in Animals 
0 Comments