Asexual reproduction involves a single parent to produce offspring without the formation of gametes. It occurs by the following ways: Fission, Budding, Fragmentation, Spore formation and Regeneration. In one of the methods like regeneration, Planaria A is cut horizontally into three pieces – L, M and N and Planaria B is cut vertically into two equal halves – O and P. (a) Which of the cut pieces of the two Planaria could regenerate to form a complete organism? (b) Give an example of another organism which follows the same mode of reproduction as Planaria. (c) What is the meaning of ‘development’ in regeneration? OR (c) Differentiate between regeneration and fragmentation.
(a) All cut pieces (L, M, N from Planaria A and O, P from Planaria B) are capable of regenerating into a complete organism. This is because Planaria has a high regenerative ability due to specialized stem cells called neoblasts, which enable the formation of missing body parts. (b) An example of another organism that follows regeneration is the Hydra. Like Planaria, Hydra can regenerate its entire body from small fragments due to its regenerative cells. (c)In regeneration, development refers to the process by which specialized cells (stem cells) proliferate, differentiate, and organize to form the missing or damaged parts of an organism. It involves: • Proliferation: Growth and division of cells. • Differentiation: Cells specialize to perform specific functions. • Organization: Cells arrange themselves to restore the structure and functionality of the organism.
