Final answer:
Homo heidelbergensis and H. erectus have some differences. H. erectus appeared earlier, around 1.8 million years ago, and had a larger brain and different-shaped skull. Homo heidelbergensis is a variable group with characteristics from different Homo species.
Step-by-step explanation:
Homo heidelbergensis and H. erectus are both early hominin species, but they have some differences. H. erectus appeared earlier, around 1.8 million years ago, and was the first hominin to migrate out of Africa. It had a larger brain, different-shaped skull, and a nose with downward-facing nostrils. On the other hand, Homo heidelbergensis is an incredibly variable group that possessed features resembling a mix of H. ergaster, H. erectus, and modern humans. They were associated with modified dwellings and had a mosaic of characteristics from different Homo species.