CBSE Class 10 Answered

METHOD

DESCRIPTION

Binary Fission

• Most common method in unicellular organisms.
• Binary fission is the division of the parent cell.
• When the organism matures, it grows in size. Its nucleus duplicates. Cytoplasm divides in the middle.
• A single parent organism gives rise to two identical daughter organisms.
• E.g. Amoeba, Paramoecium

Multiple Fission

• The parent cell divides to produce many identical new individuals.
• E.g. Plasmodium

Budding

• A small outgrowth called bud arises on the parent body.
• The bud grows and develops mouth and a ring of tentacles.
• The bud breaks off from the parent body and develops into a new individual.
• E.g. Hydra, Sponges, Corals

Regeneration

• Regeneration is the ability of the organisms to generate lost or damaged parts.
• It occurs by the process of growth and development.
• The cells from the part that has been cut off begin to divide rapidly and form a ball of cells.
• The cells move to their proper places where they have to form different organs and body parts.
• They then change their shapes, get specialised and start forming various tissue types.
• The tissues in turn form organs and the different body parts of the living organisms.
• E.g. Lizard, Starfish, Planaria, Hydra

Spore formation

• During spore formation, the parent plant or sporophyte produces hundreds of reproductive units called spores inside the sporangia.
• When the spore case ruptures or bursts, the spores spread into the air.
• When the air-borne spores land on food, soil or any suitable substratum under favourable conditions, they germinate and give rise to new organisms with many vegetative hyphae.
• E.g. Rhizopus, Mucor, Aspergillus

Fragmentation

• The breaking up of body of organisms into two or more pieces or fragments on maturing, each of which subsequently can grow into a complete new organism is called fragmentation.  
• Fragmentation is a method of rapid multiplication that occurs naturally on its own when the parent organism matures.
• During fragmentation, the parent organism undergoes accidental breakage into small pieces or fragments.
• Each fragment then develops into a new individual plant.
• E.g. Spirogyra, Oscillatoria, Hydrilla