Final answer:
The 'predation theory' and 'arboreal hypothesis' aim to explain why primates have developed certain traits, with the former focusing on adaptations for predation and the latter on arboreal living adaptations.
Step-by-step explanation:
The 'predation theory' and the 'arboreal hypothesis' are both theories proposed to explain the same common primate trait of having adaptations suitable for an arboreal lifestyle, such as forward-facing eyes, grasping hands and feet, and the presence of nails instead of claws. The arboreal hypothesis suggests that these primate traits evolved primarily as adaptations for living in trees, aiding in mobility and grasping of branches for safety and foraging. On the other hand, the visual predation hypothesis, a variant of the predation theory, argues that these traits evolved to aid in hunting insects and small animals in the shrubby forest undergrowth and lower tiers of the forest canopy.
Key to the understanding of both these theories is natural selection, where traits that enhance survival and reproductive success become more common over generations. Predation and predator avoidance exert significant pressures on species, leading both predators and prey to develop adaptations such as camouflage through natural selection. While the arboreal theory explains the evolution of primate traits as an answer to the challenges of arboreal living, the visual predation hypothesis emphasizes these traits as enhancements for predatory capabilities in a three-dimensional environment.