epigenesis The hypothesis that an organism develops by the new appearance of structures and functions. An alternative hypothesis (termed ‘preformation’) is that the development of an organism occurs by the unfolding and growth of characters already present in the egg at the beginning of development.

epigenesis The hypothesis that an organism develops by the new appearance of structures and functions. An alternative hypothesis (termed ‘preformation’) is that development of an organism occurs by the unfolding and growth of characters already present in the egg at the beginning of development.

epigenesis The hypothesis that an organism develops by the new appearance of structures and functions. An alternative hypothesis (termed ‘preformation’) is that development of an organism occurs by the unfolding and growth of characters already present in the egg at the beginning of development.