- Comparative Anatomy: Andreas Vesalius
- Observation and Natural Theology: William Harvey & William Paley
- Fossils and the Birth of Paleontology: Nicholas Steno
- Nested Hierarchies, the Order of Nature: Carolus Linnaeus
- Old Earth, Ancient Life: Georges-Louis Leclerc, Comte de Buffon
- The Ecology of Human Populations: Thomas Malthus