Basil of Caesarea

Let the earth bring forth the living creature. Behold the word of God pervading creation, beginning even then the efficacy which is seen displayed to-day, and will be displayed to the end of the world! As a ball, which one pushes, if it meet a declivity, descends, carried by its form and the nature of the ground and does not stop until it has reached a level surface; so nature, once put in motion by the Divine command, traverses creation with an equal step, through birth and death, and keeps up the succession of kinds through resemblance, to the last. Nature always makes a horse succeed to a horse, a lion to a lion, and an eagle to an eagle, and preserving each animal by these uninterrupted successions she transmits it to the end of all things. Animals do not see their peculiarities destroyed or effaced by any length of time; their nature, as though it had been just constituted, follows the course of ages, for ever young.