Judged: two independent readers; copy check clear.
heterochrony
heterochrony Heterochrony is a historical term used for a principle of developmental acceleration in which traits that first appear in later growth stages come to show up progressively earlier in descendants, sometimes as early as embryonic life.
Heterochrony is a historical term used for a principle of developmental acceleration in which traits that first appear in later growth stages come to show up progressively earlier in descendants, sometimes as early as embryonic life. In this usage, it was invoked to explain the early appearance of certain characteristics in embryos.