Primates and Primate Evolution

Primates and Primate Evolution

 Primates evolved from mammals in the Mesozoic era about 225-65 million years. Firstly, the primates evolved during the adaptive radiation to produce archaic hominids. The earliest primates were known as the proto-primates.  They include the plesiadapiformes, such as the purgatorious, and emerged during the period of cretaceous in the Paleocene epoch Sicox, 2016). Primate evolution has been explained through various theories and fossil evidence such as the skull, the teeth, and the skeletons. However, fossil records have been insufficient in elaborating on the evolution of primates. The inadequate evidence maybe because the primates die and decompose quickly. Besides, the scavengers fed on the primates when they died, and their bodies were not preserved. The paper aims at discussing primates and their evolution.

Living primates have a suite of traits shared traits that comprise convergent eyes. Most primates depend primarily on the sense of vision compared to other animals. The eyes are located at the front of the skull and have a postorbital closure that protects the eye socket. Moreover, primates have a large and complex brain, which is twice the size of the brains of other animals of the same size. The large surface of the brain helps in navigating the complicated social life.  Most primates are the arboreal, most significant time of the experiences is spend on trees such as chimpanzees, gorillas, monkeys (Silcox & Lopez-Torres, 2017, p. 113-137).

Besides, the primates have a more extended life history compared to the other animals. Primates reproduce less often, grow slowly, and live longer. Another trait is that primates are pentadactyl having five fingers and five toes that help in grasping and climbing trees. nIn addition, primates have a strong social network and do not migrate. Primates live at a particular place for an extended period without migrating.  They establish a long- term relationship with the individuals they interact with, leading to tremendous social behavior. Moreover, primates have tactile pads for having an exquisite sense of touch when handling food and grooming, for example, humans. The primates have flattened nails behind the fingers and toes instead of the claws and hooves, which other animals lack (Silcox & Lopez-Torres, 2017, p. 113-137).

The traits primates have can be derived (synapomorphies) or primitive ( symplesiomorphies). The types of attributes help in identifying the primate species that have a close relationship. Primitive traits are those the primates inherited from a distant ancestor many years ago. For example, hairy bodies the primates have were inherited from the ancestors of mammals long ago. However, while comparing the other mammals with fish, then the hairy bodies become a derived trait, which was acquired to help the other mammals adapt to the environment they exist. Most primates have mammary glands and suckle young ones, which is yet another primitive trait that was inherited (Silcox & Lopez-Torres, 2017, p. 113-137).

On the other hand, the derived traits are those that are acquired recently and distinguishes one group of primates with the other. For instance, humans move on two limbs, differentiating them with the other primate species. Besides, if other primates that locomote on two legs sare identified, then conclusions are drawn as being closely related to the species of humans more than the pan, which include the gorillas and chimpanzee. Different species of primates can become unique from the other depending on the derived and primitive traits. It is, however, worth noting that derived and primitive can be used interchangeably, relying on the primates in question.

Nonetheless, a few features have provided by the evidence found in the fossil record, such as the postorbital closure as observed from the skull found, large brains and fingers, and thumbs that are opposable. As mentioned earlier, in the beginning, primates die, and their bodies decompose quickly, leaving behind skeletons. Thus makes it challenging to tell if the body was covered by fur or not.

The earliest primate known is the plesidapis, whose fossils were found in Africa, Eurasia, and North America. It was 55 million years ago during the Eocene epoch and looked like the present prosimians.  They had large brains, eyes, and smaller muzzles. They are related to the flying lemurs and had a small skull size with a body length of about 6 inches. Plesidapis had robust limbs that curved to form claws that enable them to climb trees. Besides, they had separated jaw for fruit-eating. The plesidapis and the plesiadapiforms have a common ancestor establishing their origin. The plesidapis existed in the Eocene epoch 55 million years ago, while the plesiadapiforms were in existence  65 to 55 million years during the paleocene era. Whereas the plesidapis had claws, the plesiadapiformes had fingers in place of claws for grasping and climbing (Scott et al., 2016, p. 343-354).

The plesidapiforms originated from North America and Europe while plesidapis originated from Africa, Eurasia, and North America. Both the plesidapis and plesidapiforms ate fruits and insects as they had a separated jaw. The plesidapis had larger brains compared to the plesidapiformes. They both had eyes located at their sides and did not have the postorbital bar for safeguarding the eye sockets. The plesidapiformes were considered to be the earliest primates as they fall into one category of the proto-primates, which was considered the earliest archaic hominids (Scott et al., 2016, p. 343-354). They had primitive traits, which were not highly evolved as the present primates. They have the same characteristics the earliest primates had, such as moving slowly. The eyes location at the sides and lack of postorbital closure signifies its existence in ancient times (Boyer et al., 2016, p. 373-419). There is a lot of literature support that considers plesidapiformes to be the earliest primate. The plesidapiforms, however, got extinct due to competition from the earliest monkeys and the cooler temperatures that were unconducive for their survival (Silcox, 2016).

The evolution of primates is a fascinating topic seeking to explain how the primates, especially the mammals, evolved to what they are today. The fossil evidence has indeed helped in conceptualizing the subject and understanding the various stages, geological period, and distribution of the earliest primates. The paper has embraced the understanding of the multiple traits shared by the primates and how they distinguish one species of the primates to the other.