Plus Two Botany Class Notes First Bell 2.0

CHAPTER 1- Text Based Exercise 

REPRODUCTION IN ORGANISMS 

Textual Exercise Answers  Part -01 

1.why reproduction is essential for organisms?

Reproduction is essential for an organism because through reproduction organism get  young one which are similar to shared characters of that organism . Reproduction becomes a vital process without which organism cannot survive for long.

2.Which is a better mode of reproduction: sexual or asexual Why ?

 Sexual mode of reproduction is better than asexual reproduction. because Sexual mode of reproduction enables creation of new variants, so that survival advantage is enhanced.

3.why is offspring formed by asexual reproduction referred  to as clone?

In this method, a single individual  (parent) is capable of producing offspring. As a result, the offspring that  are produced are not only identical to  one another but are also exact copies of their parent. clone is used to describe such morphologically and genetically similar individuals.

4.Offspring formed due to sexual reproduction have better chances of survival. Why? Is this statement always true?

 Sexual reproduction involves formation of the male and female gametes, either by the same individual or by different individuals of the opposite sex. These gametes fuse to form the zygote which develops to form the new organism.  The fusion of male and female gametes, sexual reproduction results in offspring that are not identical to the parents or amongst themselves.

In the process of  crossing over segregation of chromosomes, there are more number of elimination of unfavourable  character from offspring  as a result offspring is not identical to parents.

5.How does the progeny formed from asexual reproduction differ from those formed by sexual reproduction?

 In asexual reproduction offspring is produced by a single parent with or  without the involvement of gamete formation. As a result, the offspring that are produced are not only identical to one another but are also exact copies of their parent.  But in sexual reproduction, When two parents (opposite sex) participate in the reproductive process and also involve fusion of male and female gametes .So offspring is not Identical to parents.      

6.Distinguish between asexual and sexual reproduction. Why is vegetative reproduction also considered as a type of asexual reproduction?

In vegetative propagation,  there is no fusion of gametes. In plants, the units of vegetative propagation such as runner, rhizome, sucker, tuber, offset, bulb are all capable of giving rise to new offspring. These structures are called vegetative propagules

Asexual reproduction

Sexual reproduction

 

 

single individual

(parent) is capable of producing offspring.

Sexual reproduction involves formation of the male and female gametes, either by the same individual or by different individuals of the oppositesex.

offspring that are produced are  not only identical to

one another but are also exact copies

of their parent.

sexual reproduction

results in offspring that are not identical to the parents or amongst themselves

There is no fusion of gametes

Fusion of gametes

 

It’s faster than sexual reproduction

It is an elaborate, complex and slow process as compared to asexual reproduction.















7-What is vegetative propagation? Give two suitable examples.

In plants, the units of vegetative propagation such as runner, rhizome, sucker, tuber, offset, bulb are all capable of giving rise to new offspring . These structures are called vegetative propagules



8.Define

(a) Juvenile phase,

(b) Reproductive phase,

(c) Senescent phase.           

  (a) Juvenile phase - All organisms have to reach a certain stage of growth and maturity in their life, before they can reproduce sexually. That period of growth is called the juvenile phase.

(b) Reproductive phase -  At the end of juvenile phase enter into reproductive phase. In this phase secondary sexual characters developed.

(c) senescent phase – final stage of growth period. In this phase functional capacity decrease and breakdown of cell increases.

For Chapter -01 Textual Exercise Answers  Part -02-: Click Here