Describe the binary and multiple modes of asexual reproduction in organisms.

(i) Binary fission: It is found in unicellular animals like Amoeba, Paramoecium, Euglena, etc. After attaining an optimum size the adult individual undergoes a simple division into two daughters of equal size. It consists of division of the nucleus followed by cleavage of cytoplasm into equal parts, each having a daughter nucleus. Binary fission can occur in any place in Amoeba. It is longitudinal in Euglena and transverse in Paramoecium. The organisms undergoing binary fission are almost immortal since they never grow old but divide to form two young offspring after attaining the adult size.


(ii) Multiple fission: The mode of asexual reproduction is found in unicellular animals or protozoans, e.g., Amoeba, Plasmodium, Monocystis. The nucleus of the parent cell undergoes repeated divisions to produce a number of daughter nuclei. The cytoplasm cleaves around each nucleus simultaneously to form a number of daughter cells or individual inside a parent cell. Ultimately, under favourable conditions parent cell membrane ruptures and many daughter cells are released.