Additional Questions - Chapter 1 Reproduction in Organisms 12th Biology Zoology Guide Samacheer Kalvi Solutions - SaraNextGen [2024-2025]

Updated On May 15, 2024

By SaraNextGen

Additional Questions and Answers
1 - Mark Questions
I. Choose the Correct Answer
Question 1.
Transverse binary fission is noticed in
(a) Amoeba
(b) Planaria
(c) Ceratium
(d) Vorticella
Answer:
(b) Planaria
Question 2.
Multiple fission occurring in the oocyte of plasmodium is called
(a) Schizogony
(b) Merogamy
(c) Syngamy
(d) Sporogony
Answer:
(d) Sporogony
Question 3.
Taenia solium requires as a secondary host to complete its life cycle.
(a) Mosquito
(b) pig
(c) dog
(d) human
Answer:
(b) pig

Question 4.
Which type of parthenogenesis only females are produced?
(a) Arrhenotoky
(b) Amphitoky
(c) Thelytoky
(d) Both (a) and (b)
Answer:
(c) Thelytoky
Question 5.
Which among the following animal is not a continuous breeder?
(a) Hen
(b) Rabbit
(c) Honey bees
(d) Frogs
Answer:
(d) Frogs
Question 6.
Match the following.

Answer:
a - iii, b - iv, c - ii, d - i
Question 7.
Identify the incorrect statement regarding parthenogenesis.
(a) Development of sperm without fertilization.
(b) It was first discovered by Charles Bonnet.
(c) Honey bees exhibit incomplete parthenogenesis.
(d) Amphitoky is a type of natural parthenogenesis.
Answer:
(a) Development of sperm without fertilization.
Question 8.
Oblique binary fission is seen in
Answer:
Dinoflagellates
Question 9.
The process by which gravid proglottids of tapeworm gets cut off is called Answer: apolysis
Question 10.
The concept of regeneration was first noticed in
Answer:
Hydra
Question 11.
Fusion of small sized, morphologically different gametes is called
Answer:
merogamy

Question 12.
Identify the wrong statement.
(a) Oviparous animals lays eggs.
(b) Viviparous animals give rise to young ones.
(c) Ovoviviparous animals lays eggs and then hatch it to young ones.
(d) Amphibians are oviparous animals.
Answer:
(c) Ovoviviparous animals lays eggs and then hatch it to young ones.
Question 13.
Assertion (A): Organisms show three phases in their life cycle.
Reason (R): Juvenile phase is a degenerative phase.
(a) $A$ is correct $R$ but is incorrect.
(b) Both $A$ and $R$ are correct
(c) $\mathrm{R}$ is the correct explanation for $A$
(d) A is not correct but $\mathrm{R}$ is correct
Answer:
(a) A is correct $R$ but is incorrect.
Question 14
Match the statements.

Answer:
a - iii, b-iv, c-i, d- ii.
Question 15.
The ploidy of males produced by arrhenotoky parthenogenesis is
Answer:
haploid
Question 16.
Identify the mismatched pair.
(a) Paedogenesis - Liver fluke
(b) Strobilation - Aurelia
(c) Amphitoky - Honey bee
(d) Encystment - Amoeba
Answer:
(c) Amphitoky - Honey bee
Question 17.
Identify the proper sequence.
(a) juvenile phase, senescent phase, vegetative phase
(b) juvenile phase, maturity phase, senescent phase
(c) vegetative phase, maturity phase, juvenile phase
(d) senescent phase, juvenile phase, vegetative phase
Answer:
(b) juvenile phase, maturity phase, senescent phase
Question 18.
Match the following:

Answer:
a - iv, b - iii, c - ii, d - i
Question 19.
Which of the following types of asexual reproduction is noticed in Amoeba?
(a) Sporulation
(b) Encystment
(c) Binary fission
(d) All the above
Answer:
(d) All the above
Question 20.
Pick out the organism whose fertilization occurs internally.
(a) reptiles
(b) sponges
(c) pisces
(d) amphibians
Answer:
(a) reptiles
Question 21.
Assertion (A): Asexual reproduction is called blastogenic reproduction.
Reason (R): It is accomplished by mitotic and meiotic divisions.
(a) $A$ and $R$ are correct
(b) $A$ is correct but $R$ is incorrect
(c) Both $A$ and $R$ are incorrect
(d) $\mathrm{R}$ is the correct explanation for $\mathrm{A}$
Answer:
(b) $\mathrm{A}$ is correct but $\mathrm{R}$ is incorrect
Question 22.
Egg laying hen is an example for
(a) Thelytoky
(b) Ovovivipary
(c) Vivipary

(d) Ovipary
Answer:
(d) Ovipary
Question 23.
Assertion (A): Syngamy refers to the fusion of two haploid gametes.
Reason (R): Syngamy leads to zygote formation.
(a) $A$ and $R$ are correct.
(b) $\mathrm{A}$ and $\mathrm{R}$ are incorrect.
(c) $\mathrm{R}$ is not the right explanation for $\mathrm{A}$
(d) $\mathrm{A}$ is correct but $\mathrm{R}$ is incorrect.
Answer:
(a) $A$ and $R$ are correct.
Question 24.
Human beings are an example for breeders.
Answer:

continuous
2 - Mark Questions
Question 1.
Why asexual reproduction is called as somatogenic reproduction?
Answer:
Asexual reproduction is usually by amitotic or mitotic division of the somatic (body) cells, hence is also known as somatogenic or blastogenic reproduction.
Question 2.
Name the four types of fission seen in animals.
Answer:
Binary fission, Multiple fission, Sporulation and Strobilation.
Question 3.
Define fission.
Answer:
Fission is the division of the parent body into two or more identical daughter individuals.
Question 4.
Differentiate between transverse binary fission and longitudinal binary fission.
Answer:
Transverse binary fission:
1. Plane of division runs along the transverse axis of the organism
2. Example: Paramecium
Longitudinal binary fission:
1. Plane of division runs along the longitudinal axis of the organism.
2. Example: Euglena

Question 5.
Define Plasmotomy with example.
Answer:
Plasmotomy is the division of multinucleated parent into many multinucleate daughter individuals with the division of nuclei. Nuclear division occurs later to maintain normal number of nuclei. Plasmotomy occurs in Opalina and Pelomyxa (Giant Amoeba).
Question 6.
What do you mean by regeneration in living organisms? Mention its types.
Answer:
Regeneration is the regrowth of injured region.
It is of two types:
1. Morphallaxis
2. Epimorphosis.
Question 7.
How is the fertilization of amphibians differs from aves based on site?
Answer:
In amphibians the fertilization is external (taking place outside the body of female organism) whereas internal fertilization takes place in aves.
Question 8.
What is Paedogamy?
Answer:
Paedogamy is the sexual union of young individuals produced immediately after the division of the adult parent cell by mitosis.
Question 9.
Write a brief note on conjugation.
Answer:
Conjugation is the temporary union of the two individuals of the same species. During their union both individuals, called the conjugants exchange certain amount of nuclear material (DNA) and then get separated. Conjugation is common among ciliates, e.g. Paramecium, Vorticella and bacteria (Prokaryotes).
Question 10.
Classify animal breeding based on time.
Answer:

On the basis of time, breeding animals are of two types: seasonal breeders and continuous breeders. Seasonal breeders reproduce at particular period of the year such as frogs, lizards, most birds, deers etc., Continuous breeders continue to breed throughout their sexual maturity e.g. honey bees, poultry, rabbit etc.
Question 11.
Define Vivipary.
Answer:
Vivipary is a condition in which animals give rise to live young ones after being nourished in the uterus though the placenta.
E.g. human.
Question 12.
List out the four types of binary fission.
Answer:
1. Simple irregular binary fission
2. Transverse binary fission
3. Longitudinal binary fission
4. Oblique binary fission
Question 13.
Repeated fission is a type of multiple fission. Yes or No? Why?
Answer:
Yes. If multiple fission produces four or many daughter individuals by equal cell division and the young ones do not separate until the process is complete, then this division is called repeated fission e.g. Vorticella.
Question 14.
Define apolysis.
Answer:
The detachment of gravid proglottids either singly or in groups from the body of tapeworm is called apolysis.
3 - Mark Questions

Question 15.
Compare schizogony with sporogony of plasmodium.
Answer:
Schizogony:
1. In schizogony, the multiple fission occurs in the schizont.
2. It results in the formation of merozoites.
Sporogony:
1. In sporogony, the multiple fission occurs in the oocyte.
2. It results in the formation of sporozoites.
Question 16.
Write a short note on encystment in amoeba.
Answer:
During unfavorable conditions (increase or decrease in temperature, scarcity of food) Amoeba withdraws its pseudopodia and secretes a three-layered, protective, chitinous cyst wall around it and becomes inactive. This phenomenon is called encystment. When conditions become favourable, the encysted Amoeba divides by multiple fission and produces many minute amoebae called pseudopodiospore or amoebulae.
The cyst wall absorbs water and breaks off liberating the young pseudopodiospores, each with a fine pseudopodia. They feed and grow rapidly to lead an independent life.
Question 17.
How exogenous buds are developed by Hydra?
Answer:
When buds are formed on the outer surface of the parent body, it is known as exogenous budding e.g. Hydra. In Hydra when food is plenty, the ectoderm cells increase and form a small elevation on the body surface. Ectoderm and endoderm are pushed out to form the bud. The bud contains an interior lumen in continuation with parent's gastrovascular cavity. The bud enlarges, develops a mouth and a circle of tentacles at its free end. When fully grown, the bud constricts at the base and finally separates from the parent body and leads an independent life.

Question 18.
Apolysis favours Taenia solium. How?
Answer:
In the tapeworm, Taenia solium the gravid (ripe) proglottids are the oldest at the posterior end of the strobila. The gravid proglottids are regularly cut off either singly or in groups from the posterior end by a process called apolysis. This is very significant since it helps in transferring the developed embryos from the primary host (man) to find a secondary host (pig).
Question 19.
What is autogamy?
Answer:
In autogamy, the male and female gametes are produced by the same cell or same organism and both the gametes fuse together to form a zygote
e.g. Actinosphaerium and Paramecium.
Question 20.
What is exogamy?
Answer:
In exogamy, the male and female gametes are produced by different parents and they fuse to form a zygote. So it is biparental. e.g. Human - dioecious or unisexual animal.
Question 21.
Give the definition for
1. Arrhenotoky
2. Thelytoky
3. Amphitoky
Answer:
1. Arrhenotoky: In this type only males are produced by parthenogenesis eg: honey bees
2. Thelytoky: In this type of parthenogenesis only females are produced by parthenogenesis.
e.g: Solenobia
3. Amphitoky: In this type parthenogenetic egg may develop into individuals of any sex. e.g: Aphis.
Question 22.
What is Incomplete parthenogenesis? Explain with example.
Answer:
Incomplete parthenogenesis is a type of reproduction in which both sexual reproduction and parthenogenesis occurs. Example: In honey bees, the fertilized eggs develop into queen bee and worker bees, whereas the unfertilized eggs develop into drones (male).
Question 23.
Explain briefly on the nature of Ovovivipary.

Answer:
In Ovoviviparous animals, the embryo develops inside the egg and remains in the mother's body until they are ready to hatch. This method of reproduction is similar to viviparity but the embryos have no placental connection with the mother and receive their nourishment from the egg yolk. Ovoviviparity is seen in fishes like shark.
Question 24.
Point out any six modes of asexual reproduction seen in animals. Answer:
1. Fission
2. budding
3. fragmentation
4. sporulation
5. regeneration
6. gemmule formation.
Question 25.
Enumerate the types of syngamy.
Answer:
1. Autogamy
2. Exogamy
3. Hologamy
4. Paedogamy
5. Merogamy
6. Isogamy
7. Anisogamy
8. Conjugation
Question 26.
Name the types of animals based on embryonic development with an example for each. Answer:
1. Oviparous animals e.g. Birds
2. Viviparous animals e.g. Human beings

3. Ovoviviparous animals
e.g. Shark
Question 27.
Write a short note on phases of life cycle.
Answer:
1. Juvenile phase - Period of growth between birth of an individual and reproductive maturity.
2. Reproductive phase - Period of growth when an organism attain reproductive maturity and produces new off springs.
3. Senescent plane - Period of growth when the structure and functioning of body starts degenerating.
Question 28.
What is a Paedogenesis?
Answer:
In paedogenetic parthenogenesis (paedogenesis) the larvae produce a new generation of larvae "by parthenogenesis. It occurs in the sporocysts and Redia larvae of liver fluke. It is also seen in the larvae of some insects, e.g. Gall fly.
Question 29.
Draw and label a gemmule of sponge.
Answer:

Question 30.
Differentiate between asexual and sexual reproduction.
Answer:
Asexual Reproduction:
1. Involves only one parent
2. Only mitotic cell division takes place.
3. Off springs are genetically identical to parent.
4. Gametes are not produced
Sexual Reproduction:
1. Involves two parents (male \& female)
2. Both mitosis \& meiosis takes place.
3. Off springs genetically differ from the parents.
4. Gametes are produced.
5 - mark Questions
Question 31.
Describe the regeneration process noticed in living organism.
Answer:
Regeneration is regrowth in the injured region. Regeneration was first studied in Hydra by Abraham Trembley in 1740. Regeneration is of two types, morphallaxis and epimorphosis. In morphallaxis the whole body grows from a small fragment e.g. Hydra and Planaria. When Hydra is accidentally cut into several pieces, each piece can regenerate the lost parts and develop into a whole new individual. The parts usually retain their original polarity, with oral ends, by developing tentacles and aboral ends, by producing basal discs.
Epimorphosis is the replacement of lost body parts. It is of two types, namely reparative and restorative regeneration. In reparative regeneration, only certain damaged tissue can be regenerated, whereas in restorative regeneration severed body parts can develop e.g. star fish, tail of wall lizard.
Question 32.
Given an account on following terms.

1. Hologamy
2. Isogamy
3. Anisogamy
4. Merogamy
5. Paedogamy
Answer:
1. Hologamy: In Hologamy, the adult individuals do not produce gametes, but they themselves act as gametes and fuse to form new individuals.
E.g : Trichonympha
2. Isogamy : Fusion of morphologically \& physiologically similar gametes.
E.g : Monocystis.
3. Anisogamy: Fusion of morphologically \& physiologically dissimilar gametes. Eg: Vertebrates.
4. Merogamy : Fusion of small sized morphologically different gametes (merogametes)
5. Paedogamy : Fusion of young individuals produced immediately after the mitotic division of adult parent cell.
Higher Order Thinking Stills (HOTs) Question
Question 1.
Under threat or attack, garden lizard loses a part of its tail which trembles and avert the attention of predators, so that the lizard escapes later the tail regrown for lizard. The same phenomenon can also be noticed in organisms like starfish etc. What do you call this phenomenon? Define it.
Answer:
Regeneration is the regrowth in the injured region.
Question 2.
Complete the table.

Answer:
A - Only males
B - Only Females
C - Both Males \& Females
Question 3.
In Vivipary, how the developing embryoes are nourished?
Answer:
In Vivipary, the embryo develops inside the womb of females body, hence they are nourished by the mother through placenta.
Question 4.
How Charles Bonnet and Abraham Trembley contributed to Biological filed?
Answer:
Charles Bonnet discovered the process of parthenogenesis. Abraham Trembley was the first to study the concept of Regeneration in the Hydra
Question 5.
' $A$ ' and 'B' are the male \& female sex cells respectively which look alike and performs similar functions. ' $A$ ' and ' $B$ ' fuse to form a new individual ' $D$ ' Which type of gametic fusion does this represent? Give an example.
Answer:
Isogamy Eg: Monocystis
Question 6.
Complete the flow chart by mentioning the ploidy of cells in boxes.
Answer:

1. Queen Bee Worker Bee - Diploid (2n)
2. Drones (Male Bee), Egg, sperm - Haploid (n)
Question 7.
Meiosis is a type of cell division where the chromosomal number is reduced to half the number daughter cells. Which type of cellular division occurs in the drones to produces spermatozoa?
Why?
Answer:
The gonadal cells of drones undergo mitosis to form sperms. Because the drones are haploid in nature since they develop from unfertilized eggs. To avoid further reduction in chromosome no. and maintain the chromosomal constancy, (instead of undergoing meiosis), mitosis will take place leading to formation of haploid gametes.