Answer
The main differences between radial and spiral cleavage are how the cells cleave (reproduce) in early embryonic development. In radial cleavage, there is symmetry across the polar axis and multiple layers arise, but in spiral cleavage, the planes proceed diagonally and unequally along alternating lines.
Work Step by Step
Radial cleavage refers to cleavage that produces layers (tiers) of cells, which are symmetrical across the polar axis and in which each blastomere is directly above the next tier's blastomere. (p. 467)
Spiral cleavage refers to development cleavage with planes diagonal to the polar axis and the development of unequal cells along alternate lines (clockwise / counterclockwise) (p. 469)
