Modifications

Modifications, changes in organisms, both plant and animal, caused by various conditions of nutrition and environment. The term M. was first proposed by Nageli, who pointed to their transient nature. These changes are not inherited, and therefore must be distinguished from mutations (see), or hereditary changes. The magnitude of changes in defining the concepts of M. and mutations is not important. Very large changes in organisms can only be transient M. In the statistical study of M., a normal variation curve is found. A special group is represented by long-term M.; their peculiarity consists in that, in contrast to M. of the usual type, they remain constant for many generations. Long-term modifications (see) have great significance for resolving the question of the heritability of acquired characteristics and therefore deserve to be выделены into a special group. On M. in the physical sense-see Allotropy-.

Junipers: 1-common Juniperus communis; 2-Cossack Juniperus sabina.

normal variation curve. A special group is represented by long-term modifications; their peculiarity consists in that, in contrast to modifications of the usual type, they remain constant for many generations. Long-term modifications (see) have great significance for resolving the question of the heritability of acquired characteristics and therefore deserve to be выделены into a special group. On modifications in the physical sense-see Allotropy-.