Final answer:
A phylogenetic tree indicates major evolutionary events within a lineage by highlighting the common ancestry of species.
Step-by-step explanation:
A phylogenetic tree is a diagram that shows the evolutionary relationships between biological species based on similarities and differences in traits. It indicates major evolutionary events within a lineage by highlighting the common ancestry of species. The internal nodes on the tree represent ancestors and the branching points represent when an ancestor diverged to form two new species. The length of each branch on the tree is proportional to the time elapsed since the split.