Aristotle (384-322 BCE)
"The Father of Biology"

    Aristotle was a student of Plato (ca. 428~423 – 348~347 BCE) (they are respectively the white-haired and dark-haired figures at the center of Raphael's 1511 fresco of the School of Athens), and the author of several books describing in detail the natural history of creatures in and about the Aegean Sea near Greece. He attempted one of the first systematic of living organisms, and developed a theory of progressive evolution, based on development of simpler to more complex organisms.

    Plato was himself the student of Socrates (470-399 BCE): the mnemonic for the historical order is SPA.