Transformation of a single–celled zygote (fertilized egg) into an organism results from three interrelated processes: namely cell division, cell differentiation and morphogenesis. Cell division alone, however, would produce only a great ball of identical cells, nothing like an animal or plant. During embryonic development, cells not only increase in number, but also undergo cell differentiation, the process by which cells become specialized in structure and function. Moreover, the different kinds of cells are not randomly distributed but are organized into tissues and organs.
The physical processes that give an organism its shape constitute morphogenesis, meaning "creation of form". The processes of cell division, differentiation, and morphogenesis overlap in time. Morphogenetic events lay out the basic body plan very early in embryonic development, establishing, for example, which end of an animal embryo will be the head or which end of a plant embryo will become the roots. These early events determine the body axes of the organism, such as the anterior–posterior (head–to–tail) axis and the dorsal–ventral (back–to–belly) axis. Later morphogenetic events establish relative locations of structures within smaller regions of the embryo, such as the fins on a fish, or the digits on a vertebrate limb–and then within regions still smaller.
Stem cells are biological cells found in all multicellular organisms
These can divide (through mitosis) and differentiate into diverse specialized cell types and can self–renew to produce more stem cells Cell division and differentiation play important roles in morphogenesis in all organisms. Morphogenesis and growth in overall occur throughout the life of the plant. Morphogenesis, the shaping of an organism by embryological processes of differentiation of cells, tissues, and organs and the development of organ systems according to the genetic "blueprint" of the potential organism and environmental conditions.
Totipotency is the ability of a single cell to divide and produce all of the differentiated cells in an organism, and example totipotent cells are spores and zygotes. Pluripotency refers to a stem cell that has the potential to differentiate into any of the three germ layers: endoderm (interior stomach lining, gastrointestinal tract, the lungs), mesoderm (muscle, bone, blood, urogenital), or ectoderm (epidermal tissues and nervous system).