Sample Paper on Essay 2

Brief Overview

In essence, the origin of the New World monkeys (Platyrrhine primates) remains an unsolved mystery to many scholars and Anthropologists. This document analyses the unlikelihood of Platyrrhine having an origin in the New World. Similarly, the document describes the available evidences explaining why it is difficult to comprehend how Platyrrhine could have gotten into the New World. In addition, the possible solutions to the mystery surrounding the origin of the Platyrrhine primates are explicitly given in this document.           Question A

In biology, homology refers to features (traits) that are shared by certain species primarily due to a possibility of a common ancestry while an analogy explains a similarity in characteristics not attributed to common ancestors. As such, from phylogeny, the Platyrrhine and the Catarrhines are placed under Haplorrhini clade, a proof of common ancestry. Arguably, the original habitat of primates on the South American continent has for some time now been a subject of discussion. For instance, to some Anthropologists, the existence of the Platyrrhine can be traced in the New World while the Catarrhines have mostly been traced in the Old World. However, both the Platyrrhine and Catarrhines do share many homologous traits given the assumption of common ancestry.

For instance, the presence of a dry nose on both primates and the absence of tapetum lucidum and postorbital closure on both among other inherent features explains the possibility of a common lineage. Notably, the above-described conditions can similarly be traced to the African continent from a common lineage with the haplorhines. To other Anthropologists, the Platyrrhine may have ascended when their common ancestors migrated through the broken parts of the African continent and floated into the new world. This explains why some Anthropologists claim that the Platyrrhine may have not originated from the New World as commonly propagated. Most of the current archeological evidence also points at Africa as a possible original habitat of the Platyrrhine primates.

Question B

According to most archeological data, the continent of South America was arguably separated from the African continent during the Mesozoic era making it hard to explain the exact way the Platyrrhine and Catarrhine primates reached the continent. Much more evidence points at Africa as a conceivable origin of the Platyrrhine monkeys. For instance, the ocean currents during that period would have only made it possible for the Platyrrhine monkeys to cross from Africa into the South American continent and not into the New World. In essence, the very first fossil of the Platyrrhine monkeys can be traced back to the late Oligocene period making it possible to argue that the Platyrrhine might have originated from South America. Correspondingly, other morphological traits also relates the Platyrrhine monkeys with the Oligocene of the African continent. Other morphological characteristics suggest that Platyrrhine of South America claim their origin and ancestry to the African continent. In addition, no evidence points to North America as a possible origin of the Platyrrhine monkeys given that no notable anthropoid evidence were ever found in the continent.

The continent of Africa and South America are divided by an approximate distance of 300km. This suggests that the two continents may have been closer to each other than they are now making it possible for the Platyrrhine species to migrate. This can be explained from the theory of continental drift that propagated that initially, the world was once a one big mass that shifted positions due to some tectonic forces. Notably, most of the Platyrrhine fossils discovered on the African and South American continent and other parts of the world belongs to the modern Platyrrhine. This makes it difficult to ascertain the exact origin of the Platyrrhine monkeys. Similarly, most Anthropologists finds it hard to make a distinction on the various characteristics the New World monkeys and the Neogene Platyrrhine share.

Question C

The few fossils of the Platyrrhine primates discovered cannot adequately ascertain whether primates originated from the New or Old World. Most of the fossil records on the Platyrrhine monkeys are incomplete and unreliable making the origin of their origins a puzzle to most Anthropologists. For instance, most of the body parts of the Platyrrhine are considered soft and could not withstand the decay processes after million years. As such, most of the fossils are associated with the modern Platyrrhine primates and not the contemporary monkeys.

The puzzle explaining the origin of the Platyrrhine primates can be explained through two possible ways. For instance, one can argue that through a thorough analysis of the earliest primate fossils, the exact origin of the Platyrrhine primates can be ascertained. Using the fossil calibration restraints, the most recent lineage of the Platyrrhine monkeys can be ascertained easily. In addition, most Anthropologists assume that the morphological states that are observed in the fossils of the modern Platyrrhine reflect the primitive traits. Therefore, the trends in morphological traits from the fossil specimens and extent of diversity especially in dental forms can be used to trace the exact origin of the Platyrrhine primates. In addition, it can be argued that the Platyrrhine monkeys (New World primates) are immigrant mammals given the large number of fossil sediments discovered in Africa and South America.