What is the process of cleavage?

Cleavage is the process of cell division that occurs immediately after fertilization in an embryo. It divides the fertilized egg (zygote) into smaller cells called blastomeres without increasing total size.

Steps of cleavage

• Fertilization forms the zygote.
• The zygote undergoes rapid mitotic divisions.
• Cells get smaller with each division, forming a multicellular structure called a morula.
• Eventually, the morula becomes a blastula.

Types of cleavage

• Holoblastic cleavage: Complete division of the egg (in amphibians and mammals).
• Meroblastic cleavage: Partial division (in birds and reptiles).