Final answer:
Homo heidelbergensis had a larger average brain size, a more pronounced brow ridge, and a thicker skull compared to Homo erectus. Although they shared the receding chin feature, H. heidelbergensis exhibited a shift towards less robust facial features and maintained long legs for endurance.
Step-by-step explanation:
Homo heidelbergensis differs from its likely ancestor Homo erectus in several anatomical features. The changes reflect adaptations and evolution of the species. Notably, H. heidelbergensis had a larger brain size, averaging 1,200 to 1,400 cubic centimeters, compared to the 775 to 1,100 cubic centimeters of H. erectus. This increase in brain size is a general trend observed in the evolution of hominids. In addition to brain size, H. heidelbergensis had a more pronounced brow ridge and a thicker skull than H. erectus. Though they shared the trait of a receding chin, the facial features of H. heidelbergensis were less robust than those of H. erectus, indicating a shift towards more modern anatomical structures. Long legs and a stature similar to modern humans, an evolutionary trait of H. erectus, were also typically seen in H. heidelbergensis, suggesting good endurance capabilities for hunting and travelling over long distances.