Reproduction in Organisms Class 12 Notes

Reproduction is a biological process of producing their young ones, which are identical to their parents. This process plays an important role in the continuity of the species, generation after generations. Reproduction is usually carried out by all living organisms from a single celled amoeba to the multicellular organisms. There are two modes of reproduction and are classified mainly based on the participation of one or both the parents.

Types of Reproduction

Asexual Reproduction

In this mode of reproduction, a new offspring is produced by the involvement or participation of a single parents only. The produced offspring are not only identical but are also the exact copies of their parent because in this process a single parent divides itself to reproduce its offspring.

The different types of asexual reproduction are as follows:

  • Budding.
  • Fragmentation.
  • Binary fission.

Examples of asexually reproducing organisms:

Asexual reproduction is common among:

  1. Single-celled organisms, such as Amoeba, Bacteria, Hydras, yeast cells, etc. In which, Amoeba and Bacteria reproduce by binary fission, Hydras, yeast cells reproduce by budding.
  2. Few plants species including, Ginger, potatoes, sugarcane, Agave, Bryophyllum, etc. reproduce through vegetative propagation.
  3. Few animal species including, starfish, black worms, etc. reproduce using fragmentation.

Sexual Reproduction

In this mode of reproduction, a new offspring is produced by the participation of two parents of the opposite sex. This type of reproduction is seen in all multicellular organisms including birds, reptiles, dog, cat, cattle’s, elephants, etc. The complete process of sexual reproduction consists of a set of events, including:

  • Pre-fertilization.
  • Fertilization.
  • Post-fertilization.

Few Important Questions

  1. What is a bisexual flower?
  2. What is vegetative propagation?
  3. Distinguish between Asexual and Sexual Reproduction?
  4. Distinguish between Gametogenesis and Embryogenesis?

Learn more about reproduction and their types from the topics given below:


Practise This Question

Some statements about isomerism are given 

(I) n - propyl amine and isopropyl amine are position isomers 
(II)n - butyl amine, isobutyl amine are chain isomers 
(III)n - propyl amine and tri methyl amine are functional isomers 

(IV)di ethyl amine and n - propyl methyl amine are metamers The correct statements are