ICSE Class 8 Answered

Reproduction in Amoeba under favourable conditions:

• Amoeba reproduces primarily by binary fission.
• 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.

Reproduction in Amoeba under unfavourable conditions:

• A method known as multiple fission is adopted by the unicellular organism Amoeba to survive and reproduce under unfavourable conditions.
• When the conditions are unfavourable, Amoeba withdraws its pseudopodia and becomes almost round.
• It secretes a hard covering called cyst. The cyst forms a thick protective coat around it.
• Inside the cyst, the nucleus undergoes repeated divisions to form many nuclei.
• Nuclear division is followed by the division of cytoplasm.