Final answer:
Cleavage is a process in embryonic development that involves several mitotic divisions of a fertilized egg, leading to the formation of a morula and then a blastocyst, which are necessary stages before an embryo can grow and implant in the uterine wall. This process is crucial for achieving the correct cell number and positioning for further development and is a standard practice in in vitro fertilization (IVF) procedures to enhance pregnancy rates.
Step-by-step explanation:
The purpose of cleavage in embryonic development is to reach a certain number of cells before the embryo begins to grow and to accelerate embryogenesis. Cleavage refers to the first several mitotic divisions that a fertilized egg undergoes, resulting in a solid ball of cells known as the morula. This is followed by the development into the blastocyst stage before potential implantation into the uterine wall. The process of cleavage ensures that the embryo has the correct cell number and is properly positioned to initiate further developmental stages. In clinical settings, such as with in vitro fertilization (IVF), fertilized eggs are often cultured until they reach the blastocyst stage, as this has been shown to result in a higher pregnancy rate.