Which cell movements and shape changes contribute to morphogenesis?

Morphogenesis, the process by which an organism develops its shape, relies on distinct mechanisms in plants and animals.1

Plant Morphogenesis

In plants, morphogenesis is primarily driven by differential growth. The two key factors are:1
* Orientation of cell division: The planes in which cells divide determine the direction of tissue expansion.2
* Directional cell expansion: Once cells are formed, their shape is dictated by how they expand. This process is regulated by microtubules in the cytoplasm, which influence the construction of the cell wall and the deposition of cellulose.2

Animal Morphogenesis

Animal morphogenesis is accomplished through both growth and active cell movement. While some simple biological structures arise through the self-assembly of cells—where cells adhere and rearrange themselves into specific regions—normal development typically involves cells that remain in constant contact. In these masses, morphogenetic changes are produced by:13
* Differential adhesion: Changes in the intensity of adhesion between neighboring cells.3
* Surface-to-volume changes: Alterations in the proportion of cell surface area relative to cell volume.3