Practice question

Regulative development emphasizes ongoing plasticity and environmental instruction of cell fate. Blastomere fates are not preassigned; instead, continuous dialogue via secreted morphogens, juxtacrine Notch signaling and mechanical cues guides differentiation and spatial organization. If cells are lost experimentally or embryos split, neighbors adjust gene expression to compensate, producing normal embryos or identical twins. Mammals, sea urchins and urodele amphibians illustrate this flexibility, enabling regeneration after ablation and self-organization of embryonic fields. Such regulative ability reflects potency greater than fate and characterizes embryos as dynamic adaptive systems rather than assembly.