What is Regeneration?

Would it not be wonderful if people who lost an arm or a leg or even a finger in an accident could simply grow another one in its place? But in reality it does not happen in case of human beings. However, you will be surprised to know that there are some living beings in which a new limb

develops at the point from where the original limb has been lost. Development of a new part in place of a lost part is known as regeneration. Some creatures have the unique ability to regenerate their body parts. If small arm of a starfish is cut off or destroyed, it is regenerated. The hydra is also endowed with this wonderful capability of regeneration.
The ability of regeneration is different in different creatures. Living beings with complicated structures have lesser ability of regeneration. Man and other mammals have complex constitution. That's why they have lesser ability of regeneration. Because of lesser ability of regeneration, once our legs or hands are cut, they are not regenerated. Though in our body also, some type of regeneration takes place. For example, if the skin in any part of the body is burnt or cut, new skin comes up there again. Regrowing of wings of birds is another example of regeneration.
In some species new tissues grow from the surface of the wound and replace lost or damaged tissues. Sometimes, the tissues that an organism regenerates, are different from original tissues. The regenerated structure may be smaller than the original.