Vertebrate embryonic development. Historical artwork showing the development of an embryo from cleavage (top left) to gastrulation (bottom right). In the top two rows the embryo is a solid ball of cells that is growing simply by each cell doubling in number. During the next stage (blastulation,left,third row) the cells begin to move towards the edge of the ball,leaving a fluid-filled cavity. Next is gastrulation (right,third row),where cells at one position start to move inwards forming a tube. The cells also differentiate into the 3 germ layers; the ectoderm (outer),endoderm (inner) and mesoderm (middle). Illustration by Ernst Haeckel | |
Licence : | Droits gérés |
Crédit: | Science Photo Library / Kulyk, Mehau |
Taille de l’image : | 3467 px × 5184 px |
Model Release : | Non requis |
Property Release : | Non requis |
Restrictions : | - |