Differentiation

Differentiation, that organic progress which occurs when certain parts of a uniform whole become structurally different from the others, or when, in other words, the homogeneous becomes heterogeneous. Inequality in internal and external conditions of life brings about restriction of certain vital processes and the predominance of others, and as this division of function is established, diversity of structure results. Differentiation is the structural change which is associated with the physiological 'division of labour,' and the process is essentially the same whether it find expression in cells, tissues, organs, or entire organisms. See DIVISION OF LABOUR, EVOLUTION, VARIATION, &c.