No species remains constant: that great renovator of matter
Nature, endlessly fashions new forms from old: there's nothing in the whole universe that perishes, believe me; rather it renews and varies its substance. What we describe as birth is no more than incipient change from a prior state, while dying is merely to quit it. Though the parts may be transported hither and thither, the sum of all matter is constant.

Metamorphoses (Transformations)