What is regeneration? Give one example.Why it does not occur in amoeba?
Answers
Regeneration, as one aspect of the general process of growth, is a primary attribute of all living systems. Without it there could be no life, for the very maintenance of an organism depends upon the incessant turnover by which all tissues and organs constantly renew themselves. In some cases rather substantial quantities of tissues are replaced from time to time, as in the successive production of follicles in the ovary or the molting and replacement of hairs and feathers. More commonly, the turnover is expressed at the cellular level. In mammalian skin the epidermal cells produced in the basal layer may take several weeks to reach the outer surface and be sloughed off. In the lining of the intestines, the life span of an individual epithelial cell may be only a few days.
Regeneration is the ability of an organism to shed its body part and grow a new one of instead of that.
Situations in which it is used are:
1) When the organism is attacked by a predator and the organism wants to run away then it sheds a body part as a distraction, then grow it again.
Eg) Starfish
2) When a organism is injured then it can grow the body part again.
Eg) A lizard can grow its tail again.
3) Very few organism use it as a method of reproduction.
Eg) Planaria, it divides it body in several pieces and each piece grows and becomes a new individual organism.
Amoeba is a unicellular organism so it doesn't have any body part or organ to shed, as it is made up of a single cell