Regeneration In Biology

In biology, regeneration is the process of renewal, restoration, and growth that makes genomes, cells, organisms, and ecosystems resilient to natural fluctuations or events that cause disturbance or damage.[1] Every species is capable of regeneration, from bacteria to humans.[2][3] Regeneration can either be complete[4] where the new tissue is the same as the lost tissue,[4] or incomplete[5] where after the necrotic tissue comes fibrosis.[5] At its most elementary level, regeneration is mediated by the molecular processes of gene regulation.[6][7] Regeneration in biology, however, mainly refers to the morphogenic processes that characterize the phenotypic plasticity of traits allowing multi-cellular organisms to repair and maintain the integrity

The case of autotomy, for example, serves as a defensive function as the animal detaches a limb or tail to avoid capture. After the limb or tail has been autotomized, cells move into action and the tissues will regenerate.[12][13][14] Limited regeneration of limbs occurs in most fishes and salamanders, and tail regeneration takes place in larval frogs and toads (but not adults). The whole limb of a Salamander or a Triton will grow again and again after amputation. In reptiles, Chelonians, crocodiles and snakes

Many annelids are capable of regeneration.[28] For example, Chaetopterus variopedatus and Branchiomma nigromaculata can regenerate both anterior and posterior body parts after latitudinal bisection.[29] The relationship between somatic and germline stem cell regeneration has been studied at the molecular level in the annelid Capitella teleta.[30] Leeches, members of the Annelid subclass Hirudinid, are incapable of segmental regeneration.[31] Furthermore, their close relatives, the branchiobdellids, are also incapable of segmental regeneration.[31][32] However, certain individuals, like the lumbriculids, can regenerate from only a few segments.[31] Segmental regeneration in these animals is epimorphic and occurs through blastema formation.[31] Segmental regeneration has been gained and lost during annelid evolution, as seen in oligochaetes, where head regeneration has been lost three separate