Final answer:
Cranial fossils are the skull bones, including the cranial fossae, while post-cranial fossils comprise the rest of the skeleton excluding the skull. They are crucial for studying evolutionary relationships and organismal adaptations in paleoanthropology.
Step-by-step explanation:
The difference between cranial and post-cranial fossils relates to the parts of the skeleton they represent. Cranial fossils consist of the bones of the skull, which include the cranial fossae—spaces within the skull that conform to the shape of the brain regions they contain. The cranial fossae are divided into the anterior, middle, and posterior fossae, each with specific boundaries and midline structures that divide them into right and left areas.
In contrast, post-cranial fossils refer to the skeletal remains that are part of the body not including the skull. This includes the vertebrae, ribs, pelvis, and limbs. These fossils are crucial in understanding the locomotion, behavior, and physiology of past organisms, including humans and their ancestors. In paleoanthropology, the study of early hominins often relies on the examination of both cranial and post-cranial remains to infer evolutionary relationships and adaptations.
Comparing common fossils, as seen in Exercise 7.2, involves sketching and describing observable differences. These comparisons can be challenging when distinguishing between species with overlapping traits, especially in the case of early hominins like Homo habilis, whose post-cranial features may not be as well established as their cranial counterparts.