Final answer:
The most primitive of lower primates are the Strepsirrhini or Prosimians, including creatures like lemurs and bush babies, which are smaller and have larger olfactory centers than their more evolved primate relatives.
Step-by-step explanation:
The Strepsirrhini or Prosimians are considered the most primitive of lower primates. They evolved earlier than other primates, are generally nocturnal, and tend to have smaller brains in comparison to anthropoids. The order Primates is divided into two main groups: the Prosians, which include the bush babies, the lemurs of Madagascar, and the lorises, pottos, and tarsiers of Southeast Asia; and the Anthropoids, which include the monkeys, apes, and humans. Prosimians are distinguishable by their large olfactory centers in the brain, which is indicative of their reliance on smell. Unlike Anthropoids, Prosimians typically have larger eyes relative to their head size, a trait that aids in their nocturnal lifestyle. Over time, as primates evolved, traits such as larger brains and smaller muzzles became more predominant, especially among Anthropoids, leading to the development of apes and humans.