Lakhmir Singh & Manjit Kaur: Reproduction In Animals- 3 | Lakhmir Singh & Manjit Kaur Solutions: Class 8 Science PDF Download

Q.61.
(A) Explain the term ‘fertilization’. Describe the process of fertilization in human beings.

The fusion of male and female gametes to form zygote is known as fertilization. The process of fertilization takes place in the fallopian tube (oviduct). As sperm enter into the vagina through the process of copulation; it moves upwards and enter into the oviduct. In the oviduct, ovum fuse with the sperm to form zygote.

(B) Draw a labeled diagram to show the fertilization of a human egg by a sperm to form a zygote.

Q.62.
(A) What type of couples are helped to have babies by the in vitro fertilization technique ?

In vitro fertilization technique is used to help those couples in having babies who can produce sperms and ovum but fertilization does not take place inside the woman’s body due to blocked oviducts.

(B) Describe the ‘in vitro fertilization’ technique of reproduction in humans.

In IVF or invitro fertilization technique, is a process by which an egg is fertilised by the sperm outside the body.
The process involves monitoring and stimulating a woman’s ovulatory process, removing ovum or ova (egg or eggs) from the woman’s ovaries and letting sperm fertilise them in a fluid medium in a laboratory.

Q.63.
(A) What are viviparous animals ? Give two examples of viviparous animals.

The animals which give birth to young ones are called viviparous animals. Human beings and cow are examples of viviparous animals.

(B) What are oviparous animals ? Give two examples of oviparous animals.

Those animals which lay eggs are called oviparous animals. Examples – Hens and frog.

Q.64.
(A) How does an Amoeba reproduce ? Describe with the help of labeled diagram.

Amoeba reproduces by common asexual method called binary fission. In this method, Amoeba cell divides into two equal daughter cells. The nucleus of amoeba first divides into two parts. After that the cytoplasm of amoeba divides into two parts, one part around each nucleus. This leads to the formation of the two daughter Amoebae cell having a nucleus and its own cell organelles.

Q.65. How does a Hydra reproduce ? Explain with the help of labeled diagrams.

Hydra reproduces by budding. In hydra, there may be one or more bulges. These bulges are the developing new individual and they are called buds. This bud then grows gradually to form a small hydra by developing a mouth and tentacles. The tiny new hydra detaches itself from the parent body and become new independent individual.

Q.66. Internal fertilization occurs :
(a) in female body
(b) outside female body
(c) in male body
(d) outside male body

Correct Answer is Option (a)
Fertilization which takes place inside the female body is called internal fertilization.

Q.67. The number of nuclei present in a zygote is :
(a) none
(b) one
(c) two
(d) four

Correct Answer is Option (b)
The correct answer is one nucleus is present in the zygote.
Zygote is the formed due to fertilization of the gametes. During fertilization, the nuclei of the sperm and the egg fuse to form a single nucleus.

Q.68. A tadpole develops into an adult frog by the process of :
(a) fertilization
(b) metamorphosis
(c) embedding
(d) budding

Correct Answer is Option (b)
The transformation of the larva into an adult through drastic changes is called metamorphosis. Metamorphosis occurs in frog and silk moth.

Q.69. Fertilization results immediately in the formation of :
(a) a zygote
(b) an embryo
(c) a placenta
(d) a foetus

Correct Answer is Option (a)
The process by which male and female gametes fuse to each other is called fertilization.

Q.70. Which of the following is not a part of the human male reproductive system ?
(a) tests
(b) oviducts
(c) seminal vesicles
(d) afoetus

Correct Answer is Option (b)
Oviducts is not a part of male reproductive system. It is a part of female reproductive system.

Q.71. Which of the following is not a viviparous animal ?
(a) rat
(b) lizard
(c) rabbit
(d) cat

Correct Answer is Option (b)
Rat, rabbit and cat are viviparous animals whereas lizard is a oviparous animal because it lays egg.

Q.72. The multicellular organism which reproducts by buddings is :
(a) Amoeba
(b) Yeast
(c) Paramecium
(d) Hydra

Correct Answer is Option (d)
Hydra is a multicellular organism which reproduce by budding.

Q.73. In asexual reproduction, two offsprings having the same genetic material and the same body features are called :
(a) callus
(b) twins
(c) chromosomes
(d) clones

Correct Answer is Option (d)
In asexual reproduction, two offsprings having the same genetic material and the same body features are called clones.

Q.74. Which of the following animal does not show metamorphosis ?
(a) fish
(b) frog
(c) silk moth
(d) mosquito

Correct Answer is Option (a)
Frog, silk moth and mosquito undergo metamorphosis whereas fish does not show metamorphosis.

Q.75. Asexual reproduction is :
(a) a fusion of specialized cells
(b) a method by which all types of organisms reproduce
(c) a method producing generally identical offsprings
(d) a method in which more than one parent are involved

Correct Answer is Option (c)
Asexual reproduction is a method producing generally identical offsprings.

Q.76. Which of the following organisms reproduces by binary fission ?
(a) Hydra
(b) Yeast
(c) Amoeba
(d) Sea anemone

Correct Answer is Option (c)
Amoeba, a unicellular organism reproduce by binary fission.

Q.77. Which of the following is not an oviparous animal ?
(a) snake
(b) fish
(c) rat
(d) frog

Correct Answer is Option (c)
Snake, fish and frog are oviparous animals whereas rat is viviparous animals.

Q.78. Tadpole is the larva of :
(a) fish
(b) frog
(c) mosquito
(d) butterfly

Correct Answer is Option (b)
Tadpole is the larva of frog.

Q.79. The production of an exact copy of an animal by asexual reproduction is known as :
(a) budding
(b) mating
(c) cloning
(d) hatching

Correct Answer is Option (c)
Cloning is the production of an animal by asexual reproduction.

Q.80. One of the following is not a part of the human female reproductive system. This one is:
(a) ovary
(b) uterus
(c) scrotal sacs
(d) oviducts

Correct Answer is Option (c)
Scrotal sac is a part of the human male reproductive system.

Q.81. Reproduction is essential for living organisms in order to :
(a) keep the individual organisms alive
(b) fulfill their energy requirements
(c) maintain growth
(d continue the species for ever

Correct Answer is Option (d)
Reproduction is one of the important characteristics of living things. The ability of organism to produce young ones of its own kind is called reproduction. It is essential for the continuity of species.

Q.82. One of the following occurs reproductive system of flowering plants well as that of humans. This is :
(a) sperm ducts
(b) anther
(c) ovary
(d) style

Correct Answer is Option (c)
Ovary is the structure that occurs in the reproductive system of flowering plants as well as of humans. In both of them, it produces female gametes called egg.

Q.83. In human males, the testes lie in the scrotal sacs outside the body because it helps in the :
(a) process of mating
(b) formation of sperms
(c) easy transfer of sperms
(d) all the above

Correct Answer is Option (b)
The testes are located outside the abdominal cavity in the scrotum because the temperature of scrotum is less than the normal body temperature which is requires for sperm formation.

Q.84. Characterstics that are transmitted from parents to offsprings during sexual reproduction show:
(a) only similarities with parents
(b) only variations with parents
(c) both similarities and variations with parents
(d) neither similarities nor variations with parents

Correct Answer is Option (c)
Characters that are transmitted from parents to offspring during sexual reproduction show both similarities and variations with parents.

Q.85. The offspring formed as a result of sexual reproduction exhibits more variations because :
(a) sexual reproduction is lengthy process
(b) genetic material comes from two parents of different species
(c) genetic material comes from two parents of same species
(d) genetic material comes from many parents

Correct Answer is Option (c)
The offspring formed as a result of sexual reproduction exhibits more variations because genetic material comes from two parents of same species.

Q.86. Two very small organisms X and Y both reproduce by the method of budding. Organism X is industrially very important because it is used in making alcohol from sugar. It is also used in making bread. Organisms Y is a tiny animal having tentacles which live in water.
(a) What is organisms X?

X is Yeast.
Yeasts are unicellular fungi which convert glucose into alcohol through the process of fermentation.

(b) Name the process in which X converts sugar into alcohol.

The process in which X converts sugar into alcohol is called Fermentation.
The following chemical reaction takes place:
Yeast + Glucose → Alcohol (l) + CO₂ (g)

(c) To which class of organism does X belong?

The organism X i.e. Yeast belongs to the fungi of living organisms.

Yeast is a single-cellular organism which divides by mitosis and shows budding. Fungi have the following characteristics:

• They have a cell wall.
• They have a nucleus.
• They have no chloroplasts.

(d) What are organisms Y?

Organism Y is Hydra.
Hydra is a genus of small fresh-water animals

(e) Out of X and Y, which organism is multicellular and which one is unicellular?

Yeast ( X) is a unicellular and Hydra (Y) is a Multicellular.
Yeasts are unicellular organisms because they are single-celled organisms.
Hydra are multicellular organisms with complex bodies

Q.87. A unicellular organism P lives in pond water. The organisms P has no fixed shape, its shape keeps on changing. It moves and catches its prey with the help of organs Q which keep on appearing and disappearing. The organisms P reproduces by a process R. Another organisms S also reproduces by this process. Name P, Q, R and S.

P is Amoeba ; Q is Pseudopodia ; R is Binary fission ; S is Paramecium.

Q.88. The animal A which is classified as an amphibian lays eggs in pond water. The hatching of its eggs produces a tailed-form B which looks very different from the animal A. The form B then undergoes a change C and gets converted into animal A.
(a) Name (i) animal A and (ii) form B.
(b) What is the change C known as ?
(c) name the breathing organs of A.
(d) What are the breathing organs of B?

(a) Animal A is Frog and form is Tadpole.

(b) The change from Tadpole to Frog is called as Metamorphosis.

(c) Since, A is Frog, hence the breathing organ of Frog is Lungs.

(d) Since, B is Tadpole. The breathing organ of Tadpole is gills.

Q.89. X and Y are the two types of animals. The animals like X undergo external fertilization whereas animals like Y undergo internal fertilization. The animals like X lay eggs from which baby animals are hatched. On the other hand, in animals like Y, the young one develops inside the uterus of mother which then gives birth to the baby.
(a) What is the general name of animals like X ?
(b) Give two examples of animals like X ?
(c) What is the general name of animals like Y ?
(d) Write the names if two animals like Y.

(a) General Name of Animals Like X is Oviparous. Oviparous animals are those which reproduce by laying eggs. The young ones develop inside the eggs.
(b) Examples of Animals like X are Frog, Fish and Star Fish etc.
(c) General Name of Animals Like Y is Viviparous. Viviparous animals are those animals in which the young ones develop inside the uterus of the mother.
(d) Examples of Animals like Y are Human beings, cattle, etc.

Q.90. A is an insect which breeds in ponds of stagnant water. The egg of this insect produces a worm like form B which is entirely different in appearance from the adult insects. The form B undergoes a change C and gets converted into insects A. The female of insects A is a carrier of protozoan D which spreads a disease in humans.
(a) What are A, B, C, and D ?
(b) Name another insect which also undergoes change C.

(a) A is Mosquito; B is Larva; C is Metamorphosis; D is plasmodium
(b) Butterfly is another insect which also undergoes metamorphosis.