Question

(a) What is the difference between the two asexual methods of reproduction : fission and fragmentation ? 

(b) Name one organism which reproduces by fission and another which reproduces by fragmentation. 

(c) What is meant by multiple fission ? Name one organism which reproduces by the process of multiple fission. 

(d) Describe the process of reproduction in Hydra with the help of labelled diagrams. What is the name of this process of reproduction ? 

(e) Name one unicellular organism which reproduces by the same asexual process as

Answer 1

(a) Fission 

(i) It is a process in which an organism splits to form two or more new organisms. 

(ii) Fission occurs in unicellular organisms. Example : Amoeba. 

Fragmentation 

(i) It is a process in which the body breaks up into two or more pieces on maturing, each of which subsequently grows to form a complete new organism. 

(ii) It takes place in multicellular organisms. Example : Spirogyra. 

(b) Amoeba reproduces by fission and spirogyra reproduces by fragmentation. 

(c) Multiple fission is a process in which a parent organism splits to form many new organisms at the same time. Plasmodium reproduces by multiple fission. 

(d) Hydra reproduces by budding. In hydra, first a small outgrowth called bud is formed on the side of its body by repeated mitotic divisions of its cells. This bud then grows gradually to form  a small hydra by developing a mouth and tentacles. The tiny new hydra detaches itself from the parent body and develops into a separate organism.

 (e) Yeast