Hydra, regeneration, pattern for-mation, model system, teaching tool.
Abstract
Hydra, a freshwater diploblast, with a simple but defined body plan, an organized nervous system, and the presence of stem cells, is one of the oldest model organisms used in biology. It exhibits many embryonic features even as an adult, a spectacular ability of regeneration, and lack of organismal aging. Hydra can provide insights into how complex animal forms evolved and is waiting to be better utilized in teaching.
