Related Experiment Video
Updated: Apr 28, 2026

Three and Four-Dimensional Visualization and Analysis Approaches to Study Vertebrate Axial Elongation and Segmentation
Published on: February 28, 2021
The evolutionary origin of the vertebrate body plan: the problem of head segmentation
Takayuki Onai1, Naoki Irie, Shigeru Kuratani
1Laboratory for Evolutionary Morphology, RIKEN Center for Developmental Biology, Kobe 650-0047, Japan; email: tonai@cdb.riken.jp , irie@biol.s.u-tokyo.ac.jp , saizo@cdb.riken.jp.
Abstract:
The basic body plan of vertebrates, as typified by the complex head structure, evolved from the last common ancestor approximately 530 Mya. In this review, we present a brief overview of historical discussions to disentangle the various concepts and arguments regarding the evolutionary development of the vertebrate body plan. We then explain the historical transition of the arguments about the vertebrate body plan from merely epistemological comparative morphology to comparative embryology as a scientific treatment on this topic. Finally, we review the current progress of molecular evidence regarding the basic vertebrate body plan, focusing on the link between the basic vertebrate body plan and the evolutionarily conserved developmental stages (phylotypic stages).
Related Concept Videos
Neurulation
Gastrulation
Whole Body Regeneration
Body Planes
The sagittal plane is the plane that divides the body or an organ vertically into right and left sides. If this vertical plane runs directly down the middle of the body resulting in equal division, it is called the midsagittal or median...
Cleavage and Blastulation
Convergent Evolution

