Final answer:
During the Cenozoic Era, key events in primate evolution include the appearance of the earliest primates, the emergence of fossil monkeys, and the evolution of primates, including human ancestors.
Step-by-step explanation:
The Cenozoic Era is divided into several epochs, and each epoch has key events in primate evolution. During the Paleocene epoch, the earliest unequivocal record of primates was found, represented by the creature called Purgatorius. This creature had distinct characteristics, such as an elongated last lower molar and an enlarged upper central incisor, which are shared by all living primates today. In the Oligocene epoch, the first fossil monkeys appeared, divided into two main groups: Parapithecoidea and Propliopithecoidea.
During the Tertiary Period of the Cenozoic Era, mammals called primates, including human ancestors, evolved. Modern rainforests and grasslands appeared, along with numerous flowering plants and insects. By the end of the Eocene epoch, many early prosimian species went extinct due to cooler temperatures or competition from the first monkeys.
Overall, the key events in primate evolution during the Cenozoic Era include the appearance of the earliest primates in the Paleocene epoch, the emergence of fossil monkeys in the Oligocene epoch, and the evolution of primates, including human ancestors, during the Tertiary Period.