Question

Write a short note on regeneration.

Answer 1

Hint: Every species is some way capable of reconstruction of damaged and diseased parts of the body. Some species can completely restore the lost part or organ while others may partially do so.

Complete answer:
The process of regeneration can be defined as the process of renewal or restoration of tissues of organisms that has been damaged or lost due to normal wear and tear. Regeneration can be complete or incomplete in nature. In complete regeneration, the new tissues formed are very similar to the old or lost tissues and in incomplete regeneration, the new tissues come after regeneration may not be identical to the previous ones.
Organisms as their natural tendency have the ability to regrow a lost part so that their normal functioning is restored. However, the ability of regeneration varies greatly in different groups of organisms. In newts or salamanders, complete regeneration of a lost limb or part of the body is possible but the mammals cannot undertake complete regeneration of the lost part.
The process of regeneration occurs in different groups of organisms throughout the animal kingdom. But it is better marked in lower animals such as in protozoans, sponges and coelenterates.
According to T.H.Morgan, two types of mechanisms of regeneration are observed in animals. The two types of mechanism are morphallaxis and epimorphosis. In morphallaxis, the construction of an entire animal can take place from a small fragment of the body by recognising the existing cells as in hydra. Whereas, in epimorphosis, the regeneration process takes place to replace a lost organ by proliferation of new cells from the surface of the injured part.

Additional information:
Regeneration can be of two types: reparative, in which the organism has the power to repair only damaged cells of the body and restorative process the organism can completely restore any lost part of the body as in salamanders.

Note: Regeneration is defined as the post embryonic biological process in which organisms have the tendency to repair, restore or regrow any part of the body that is damaged or lost.