Final answer:
Carolus Linnaeus divided humans into subspecies based on physical traits like shape and number of limbs, and developed the Linnaean classification system using morphological characteristics, later enhanced by genetic and biochemical information.
Step-by-step explanation:
The 18th century Swedish naturalist Carolus Linnaeus originally divided humans into subspecies based on obvious physical traits, such as the number of legs or shape of leaves.
Linnaeus developed the Linnaean classification system, grouping organisms that shared morphological traits into a hierarchical taxonomy consisting of kingdoms, classes, orders, genera, and species. His binomial nomenclature method provided each species a unique two-word Latin name, such as Homo sapiens for humans, meaning "wise human."
Although Linnaeus' classification was based primarily on morphology, with modern advances in science, scientists can now classify organisms on their biochemical and genetic similarities as well, leading to revisions in the original Linnaean system.