Reproduction in Organisms: Questions and Answers (Evaluation)

Evaluation

1. In which type of parthenogenesis are only males produced?

a) Arrhenotoky

b) Thelytoky

c) Amphitoky

d) Both a and b

Answer: a. Arrhenotoky

2. Animals giving birth to young ones:

a) Oviparous

b) Oviviviparous

c) Viviparous

d) Both a and b

Answer: c. Viviparous

3. The mode of reproduction in bacteria is by

a) Formation of gametes

b) Endospore formation

c) Conjugation

d) Zoospore formation

Answer: c. Conjugation

4. In which mode of reproduction variations are seen

a) Asexual

b) Parthenogenesis

c) Sexual

d) Both a and b

Answer: c. Sexual

5. Assertion and reasoning questions:

In each of the following questions there are two statements. One is assertion (A) and other is reasoning (R). Mark the correct answer as

A. If both A and R are true and R is correct explanation for A

B If both A and R are true but R is not the correct explanation for A

C. If A is true but R is false

D. If both A and R are false.

I. Assertion: In bee society, all the members are diploid except drones.

Reason: Drones are produced by parthenogenesis.

A   B    C    D Answer: A

II. Assertion: Offsprings produced by asexual reproduction are genetically identical to the parent.

Reason: Asexual reproduction involves only mitosis and no meiosis.

A   B    C    D Answer: A

III. Assertion: Viviparous animals give better protection to their offsprings.

Reason: They lay their eggs in the safe places of the environment.

A    B    C    D Answer: C

6. Name an organism where cell division is itself a mode of reproduction.

Amoeba reproduces by fission, that is by cell division itself a mode of reproduction.

7. Name the phenomenon where the female gamete directly develops into a new organism with an avian example.

The phenomenon is Parthenogenesis. Turkey is the bird in which the female gamete directly develops into a new organism.

8. What is parthenogenesis? Give two examples from animals

• The egg develops into a complete individual without fertilization is known as parthenogenesis.

• Example : Rotifers, Honeybees and Turkey

9. Which type of reproduction is effective -Asexual or sexual and why?

• Sexual reproduction is more effective than asexual reproduction.

• In asexual reproduction there is no variation.

• In sexual reproduction due to fusion of two gametes, variation is found.

10. The unicellular organisms which reproduce by binary fission are considered immortal. Justify.

• Amoeba is an unicellular organism, which is considered as immortal.

• The parental amoeba mitotically divides into two daughter amoebae.

11. Why is the offspring formed by asexual reproduction referred as a clone?

• The offsprings formed by asexual reproduction is genetically identical to the parent.

• They can also be referred as a clone.

• Clone is the exact copy of an organism which it is developed.

12. Why are the offsprings of oviparous animal at a greater risk as compared to offsprings of viviparous organisms?

• The offsprings of the viviparous organism develops within the female.

• The offsprings of the oviparous organisms develops in the external environment.

• There are certain external environment factors that affects the development of the offsprings.

• Hence offsprings of the oviparous animals are at greater risk.

13. Give reasons for the following:

(a) Some organisms like honey bees are called parthenogenetic animals

(b) A male honey bee has 16 chromosomes where as its female has 32 chromosomes.

a) Organisms like honey bees can reproduce without fertilization.

b) • Male honey bees are formed without fertilization (ie) Egg alone.

• Female honey bees are formed fertilization (ie) Fusion of male and female gamete.

• That is why male has 16 chromosomes in the egg

• The female are diploid having 32 chromosomes, 16 from male and 16 from female.

14. Differentiate between the following:

(a) Binary fission in amoeba and multiple fission in Plasmodium

Binary fission in amoeba

• It is a simple binary fission type.

• Contractile vacuole disappears.

• Nucleoli disintegrate

Multiple fission in plasmodium

• In plasmodium multiple fission occurs in the schizont and in the oocyte stage.

• Multiple fission in schizont stage is called schizogony and it is called merozoites.

• Multiple fission in oocyte is called sporogony and the individual is called sporozoites.

(b) Budding in yeast and budding in Hydra

Budding in yeast

• It is an asymmetrical division.

• It produces a bud like projection.

• The bud grows and enlarges.

• The nucleus also splits and enters the bud.

Budding in hydra

• It is an exogenous budding.

• Ectodermal cells projects out.

• Along with endoderm they form a bud.

• The gastrovascular cavity of the parent continues in the bud

• The bud separates and develops into hydra.

(c) Regeneration in lizard and Planaria

Regeneration in lizard

• It is epimorphosis type of regeneration.

• It is replacement of the lost part.

• It is restorative regeneration.

Regeneration in planaria

• It is morphallaxis type of regeneration.

• New planaria can develop from a small fragment of it.

• The developed plaparia will be an active individual.

15. How is juvenile phase different from reproductive phase?

Juvenile Phase:

• It is the period of growth between the birth of the individual upto reproductive maturity.

• The juvenile stage of certain organisms

Insects - Larva

Cow - Calf

Ape - Infant

Cat - Kitten

Reproductive Phase :

• The period in which the organisms are able to reproduce.

• Each organism's breeding time differs.

• If they reproduce at the particular period of the year it is called seasonal breeders.

(Eg.) Birds.

• If they are able to reproduce throughout their sexual maturity it is known as continuous breeders. (Eg.) Poultry and Rabbit.

16. What is the difference between syngamy and fertilization?

Syngamy

• It is the fusion of male and female pronuclei after fertilization.

• It confirms the diploid state of the zygote.

Fertilization

• It is the fusion of male and female gamete.

• It refers to the process of confirming fertility.