Final answer:
The greater anatomical variety found in Haplorrhines, including tarsiers and simians, compared to Strepsirrhines is due to their evolutionary adaptations, reliance on vision, and diverse habitats leading to features like larger brains and diurnal lifestyles.
Step-by-step explanation:
The anatomy of Haplorrhines is considerably more varied than that of Strepsirrhines largely due to their evolutionary adaptations and diversity of habitats. Haplorrhines, which include tarsiers and simians (New World monkeys, Old World monkeys, apes, and humans), are generally diurnal and have evolved to depend more on vision rather than smell, unlike the nocturnal Strepsirrhines with larger olfactory centers. This has led to different anatomical features such as larger brain sizes in Haplorrhines, adaptations for a diurnal lifestyle, and a reliance on sight over smell for navigation and foraging. Moreover, the Haplorrhini suborder, which is broken down into Simiiformes and Tarsiiformes, showcases a wide range of adaptive traits. For instance, New World monkeys possess prehensile tails, while Old World monkeys and apes do not. Additionally, apes—including gibbons, chimpanzees, gorillas, orangutans, and humans—are largely terrestrial and lack tails. These physical differences reflect their varied lifestyles and habitats which contribute to the anatomical diversity found within Haplorrhines compared to Strepsirrhines.