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struggle of existence. They give benefit in survival and increasing the population.
Differential reproduction increases the useful variations in the populations.

 Accumulation of variations for several generations results in new set of traits
required for survival.
As they show results after many generations, they are not important for
individual.

3. Modes of Asexual Reproduction

a) Fission
 Asexual reproduction in which a parent separates into two or more individuals
of about equal size.
 Fission can be of two types, namely, binary fission and multiple fission.
In binary fission, parent cell divides into two equal halves called daughter
cells.
 Many bacteria and protozoa simply split into two equal halves during cell
division.
 In organisms such as Amoeba, the splitting of the two cells during division can
take place in any plane.
 The daughter cells formed are identical to each other and to their parent cell.
Organisms like the amoeba, bacteria, euglena, etc., exhibit binary fission.

 However, some unicellular organisms show somewhat more organization of
their bodies, such as is seen in Leishmania (which cause kala-azar), which
have a whip-like structure at one end of the cell. In such organisms, binary
fission occurs in a definite orientation in relation to these structures.

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