What method involves grouping species based on shared derived characteristics?

The method of grouping species based on shared derived characteristics is called cladistics. Cladistics focuses on the evolutionary relationships among organisms by categorizing them into clades, which are groups that include an ancestor and all its descendants. The key aspect of cladistics is the use of synapomorphies, which are traits that are derived and shared by a group of organisms, to construct a visual representation known as a cladogram. This approach emphasizes the importance of evolutionary lineages and helps researchers understand the hierarchical relationships among different species based on their shared characteristics. Cladistics is particularly powerful in reconstructing the tree of life and understanding how various organisms are related through evolution.