Question

when does a group of cells become a multicellular individual

Answer 1

Ans. All organisms may be unicellular or multicellular begin their life as a single cell. In a unicellular organism, all the life processes are carried out by a single cell whereas in multicellular organisms special functions are carried by specialized cells. A multicellular organism increases the number of its cells by mitosis but so do unicellular organisms do. The thing which makes these groups of cells multicellular is coordination between them. Unicellular organisms also like in colonies form a group but there is no coordination among the cells in this group. But, the multicellular organism coordinate among themself due to which some cells get specialized to do some specific function due to which various functions are carried out by various specialized cells and together these cells carry out all the life processes of the organism like respiration, digestion, excretion, reproduction, etc. For the coordination purpose these organisms have signaling molecules which helps in the working of the different cells in harmony. These very features of the division of labor and coordination between different cells turns a group of cells into a multicellular individual.