Cleavage Becoming Multicellular Zygote is activated and begins to divide.
Cleavage gives rise over a number of hours to hundreds of cells.
Daughter cells are blastomeres. Patterns of cleavage influenced by distribution of egg yolk. Formation of the Blastula Blastula is a hollowed out morula. The blastomeres are pushed to the periphery. Fluid filled cavity is blastocoel.