Vertebrate embryonic development. Historical artwork showing the development of an embryo from cleavage (top left) to gastrulation (bottom right). In

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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.

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Size: 3467px × 5184px
Photo credit: © MEHAU KULYK/SCIENCE PHOTO LIBRARY / Alamy / Afripics
License: Licensed
Model Released: No

Keywords: action, anatomy, artwork, body, human, journey, journeying, journeys, motion, move, movement, moving, reproduction, reproductive, sperm, spermatozoa, system, team, teams, teamwork, togetherness, travel, travelling, travels