As human evolutionary biologists, we are deeply interested in understanding how human morphology and behavior have evolved since we split from our last common ancestors with chimpanzees roughly six or seven million years ago. Unfortunately, fossil evidence for morphology is limited and behavior does not fossilize at all. Therefore, we must use our knowledge of evolutionary principles to make inferences about the ecology and social behavior of our fossil ancestors.
Suppose that you have discovered two species of ancient fossil hominins at separate sites in east Africa. At the first site, you determine that there are at least fourteen different adult individuals of both sexes, and you have sufficient post-cranial material to estimate body sizes for males and females. You estimate that male body size is 78 kg and female body size is 45 kg. Although you did not find any complete skulls, based on study of several mandibles you discover that the teeth have high cusps and thin molar enamel. You name this species Parahomo fracticranius. This site contains fossil remains of other animals that are typically assumed to be grazers and browsers living in relatively open habitats.
The hominin material at your second site is more limited. Your material is fragmentary and appears to come from only one male and one female, but happily the female fossil has a relatively intact skull. Based on careful measurements of the fossil material, you discover that males and females both weighed roughly 22 kg and possessed molars that were large, low, and rounded in shape, with very thick enamel. You also estimate brain size as being considerably larger than you would have predicted based solely on body size. You name this species Pithecophilus sapiofeminus. In addition to your new fossil hominin fossils, this site contains fossils of several species of strictly arboreal monkeys.
Based on your knowledge of the socio-ecology of living primates and the existing hominin fossil record gleaned from lecture, discussion section, and readings, describe the socio- ecology of your two hominin species in the form of an integrated essay. You may organize your thoughts in any way that makes sense, but be sure to address the following characteristics for each species: habitat, mating system, group size, ranging behavior and territoriality, and dietary composition during different seasons. In addition, suggest an extant (i.e., living) primate species or several species that might be considered as a reasonable model(s) for each of your fossil hominins. Be sure to fully explain the logic and theory underlying your arguments.