Question

Draw diagrams to explain the regeneration that takes place in each of the body parts of Planaria when its body is cut into three pieces. Name any other organism in which a similar process can be observed.

Answer 1

Hint: In plants and animals, regeneration is the natural process of repairing or rebuilding weakened or absent cells, tissues, muscles, and even whole parts of the body to full function. For its possible applications in medicine, such as curing a number of fractures and illnesses, scientists are researching regeneration.

Complete answer:
Planaria shows the ability to develop completely new individuals from their body parts and this process of development is called regeneration. Whenever the body of Planaria is cut or broken down into many pieces, it leads to development of a complete organism from that particular piece. It can occur at any place and any part of the Planaria.

Regeneration and reproduction differ, regeneration takes place from any part of the organism, whereas the reproduction process takes place to form a new organism through specialized cells which are called gametes. On the other hand, regeneration does not assure development of new organisms always, whereas reproduction will always lead to production of new individuals from the parental organisms.

Let’s now discuss what molecular biology is taking place at the site of regeneration which leads to development. So, the cells present at the site of wound proliferate and form a blastema. This blastema differentiate into new tissues and then carries out regeneration of the missing parts of the piece of Planaria that were cut down or broken. This ability or feature designated them as immortals under the knife’s edge. Hydra also shows the similar property of regeneration.

Note: Students should remember that regeneration and reproduction are two different things and cannot be intermixed or to get confused with. Fragmentation is an asexual reproduction system in which an organism reproduces into fragments through the means of fracturing and each fragment develops into an individual organism. On the other hand, reproduction occurs as an individual regrows certain parts or limbs that have been destroyed due to predation.