A worm X found in freshwater and slow-moving streams has been accidently cut into three pieces. It was observed that in due course of time, each cut piece of the worm develops to become a complete worm by growing all the missing parts.
(a) Name the worm X which can exhibit this phenomenon of making complete worm from its cut body parts.
(b) Name another organism Y which possesses the same characteristic of growing fully from its cut body parts.
(c) What is the name of this process in which a complete organism is formed from its cut body part.
(d) State whether X and Y are unicellular and/or multicellular organisms.
(e) Can a dog be produced completely form its cut body part (say, a cut tail) just like organisms X and Y? Why?
(a) The worm X is Planaria.
(b) The organism Y which posses the same characteristic as of X is Hydra.
(c) The process in which a complete organism is formed from a lost body part of its parent is regeneration.
(d) X and Y are multicellular organisms.
(e) A dog cannot be produced from a lost body part like its tail, as this animal has a high degree of organisation in its body.
Lakhmir Biology 2013