What diagram shows the evolutionary relationships among a group of organisms?

The phylogenetic tree is the correct choice as it illustrates the evolutionary relationships among a group of organisms. This diagram represents how different species or groups are related through common ancestry, depicting their evolutionary pathways and the divergence of species over time.

Each branch point, or node, in a phylogenetic tree indicates a common ancestor, while the branches demonstrate how species have evolved and diverged. The structure allows for a visual representation of evolutionary history and can include both extant (living) species and extinct lineages.

In contrast, a taxonomic chart categorizes organisms into hierarchical classifications but does not convey the relationships of evolutionary descent. A Venn diagram is typically used to show overlapping relationships among sets but is not appropriate for representing evolutionary connections. A genetic map focuses on the arrangement of genes on a chromosome and does not illustrate the evolutionary relationships among species.