Theory of Epigenesis
(i) It was proposed by C.F. Wolff & supported by Von Baer.
(ii) Wolff proposed that germ cells contain definite but undifferentiated substances which, after fertilization becomes organized into various complex body organs (New factors) which form the adult. This idea was referred to as epigenesis.
(iii) The theory of epigenesis is similar to our present day gene concept of heredity.
(iv) Wolff rejected the preformation theory by providing detailed structure of ovum and sperm in chick.
(v) Epigenesis term was coined by William Harvey.