Yes, Linnaeus used similarities in structure to determine relationships among organisms. This is the foundation of his Linnaean taxonomy, which was a system of classifying organisms based on shared physical characteristics.

Here's how it worked:

* Hierarchical System: Linnaeus grouped organisms into a hierarchical system, starting with broad categories like Kingdom and working down to species.

* Shared Physical Traits: He used observable physical features like the number of limbs, body shape, flower structures, etc., to place organisms into these categories.

* Binomial Nomenclature: He introduced the binomial nomenclature system, giving each organism a two-part name (genus and species).

Example: He placed humans and chimpanzees in the same order (Primates) because they share physical characteristics like five fingers, five toes, and opposable thumbs.

Important Note: While Linnaeus's system was revolutionary for its time, it relied solely on physical similarities and did not consider evolutionary relationships. Modern taxonomy, which is based on evolutionary relationships, uses a wider range of evidence, including genetics, molecular data, and fossil records.

However, Linnaeus's work laid the groundwork for modern taxonomy, and his contributions to the classification of organisms are still widely acknowledged.