Theophrastus $(371 - 287 \,BC)$ is known as Father of Botany. He prepared a list of about $500$ plants and divided them into trees, shrubs, undershrubs and herbs. He also distinguished between annual, biennial and perennial plants.
These organisms also differ in size, color, habitat, physiology, and morphology.
Biologists have developed certain rules and principles supplementary which are helpful in the identification, nomenclature, and classification of organisms.