The scientist who designed a system of classifying organisms based on their physical and structural similarities is Carl Linnaeus.

He is considered the father of taxonomy, the science of classifying organisms. His system, known as the Linnaean taxonomy, uses a hierarchical system of classification, with organisms grouped into increasingly specific categories:

* Kingdom

* Phylum

* Class

* Order

* Family

* Genus

* Species

Linnaeus's work was groundbreaking for its time and laid the foundation for modern biological classification.