Binary Fission: -
i) It takes place in unicellular organisms.
ii) In this method one cell gets divided into two daughter cells under suitable
conditions.
iii) Daughter cells are identical to parent cell.
iv) In this method nucleus becomes elongated and divides into two.
v) Afterwards cell also divides into two daughter cells.
vi) For example: amoeba and paramecium reproduces with this method.
Multiple Fission: -
i) This is division of unicellular organisms into many small cells under
unfavorable conditions.
ii) The organism becomes enclosed in a cyst.
iii) Its nucleus divides into many nuclei and each nucleus surrounded by a bit
of cytoplasm.
iv) When conditions become suitable, the cyst ruptures and large number of
daughter cells are released.
v) For example: amoeba and plasmodium reproduces with this method.
Budding: -
i) In this process, an out growth (bud) develops by mitosis on the body of
parent organism.
ii) After sometime it separate from parent body and grow into an individual.
iii) For example hydra, sea anemone and sponges reproduce with this
method.
Regeneration: -
i) Regeneration means formation of lost parts of the body.
ii) For example an arm of starfish if lost in accident can grow again on the
body.
iii) Earthworm is divided into two halves; each half can regenerate its lost
half. Each half becomes an individual.
iv) Annelids, echinoderms and flatworms reproduce with this method.
Parthenogenesis: -
i) In this process an unfertilized egg develops into a complete individual.
ii) For example queen bee lays eggs, which are either fertilized to form
diploid workers, or if not fertilized it forms the haploid males called
drones.