Anthropology Case
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Humans have often wondered how we came to exist and who were the beings that came before us. There are several explanations to our existence, but the two most known or accepted is that of a creator or intelligent design and that of evolution by natural selection. Science has put forth the concept that humans like any other organism alive today has evolved from one common ancestor. From the life forms that exist today, humans are closest related to primates but to be more precise we are most related to apes and especially chimpanzees. Primates have evolved through a series of distinct stages. Below I will outline these stages and the major modifications, which took place in each. It is highly likely that the impetus for primate evolution was the adaptation to the arboreal setting and the interaction of genetic and natural selection factors.
Grade I-Lemuroids includes true lemurs, lorises and galagos and are the most primitive primates alive today. Lemurs are only found in the island of Madagascar where they were able to flourish, because of no competition from monkeys and apes. There are about 60 surviving species of lemurs on Madagascar. Because of their more primitive state lemurs have retained many ancestral characteristics like their rhinarium, a grooming claw and the fact that they mark their territories with scent. The rhinarium is a fleshy pad that most non-primate mammals have, that enhances their sense of smell. The fact that lemurs rely mostly on their sense of smell sets them apart from the rest of the primates. Lemurs and lorises both have retained a claw on their second toe much larger than the rest used to groom themselves. Lemurs also have a dental comb, that consists of their bottom incisors and canines projecting forward, a characteristic that they also share with lorises and galagos. The position in which the eyes of lemurs are in is also primitive because they are more the sides, rather than being more centered in at the middle.
Lemurs range in size and eating habits. The larger lemurs are diurnal and eat leaves, fruit, buds, and bark, while the smaller lemurs are nocturnal and eat insects. Nocturnal lemurs tend to be solitary whereas the diurnal ones tend to be in groups of 10 to 25. The lemur that I was able to observe at the zoo was the ring-tailed lemur. What I noticed was that they were making some sort if sound almost as if they were communicating with each other, something very strange. They were very calm and just sat there, either on the ground or on a tree, but I did notice that they did groom themselves.
Lorises and Galagos very similar to lemurs but they inhabit mainland areas. They were able to survive in the mainland because they took up nocturnal activity to avoid becoming extinct like their diurnal prosimian counterparts. These 8 lorises and 6 to 9 galagos species are found in India, Sri Lanka, Southeast Asia, and Africa. Lorises tend to be slow and cautious and are quadrupedal. Galagos on the other hand are very agile vertical clingers and leapers. Most are entirely insectivorous but some do eat fruit, leaves, gums, and slugs.
Lemurs and lorises are at the same evolutionary level, both have developed good visual ability, but it appears that their color vision is not as evolved as that of other primates. Their grasping and climbing abilities are also very well developed. They have a prolonged life span compared to their other mammals of such a size, lorises living about 14 years and lemurs about 19 years.
Grade II- The Tarsiers includes the primate tarsier which is small complex species. There are 5 tarsier species that are all found only in the Southeast Asia islands. They inhabit forested areas where they live amongst trees clinging to them. Tarsiers are insectivores that tend to hunt at night and to feed themselves they will usually surprise their prey by leaping from a branch. This particular primate is known to form bonds with someone that they can mate with, as a male and a female, and eventually with their offspring.
Tarsiers are a very complex primate because they seem to have a little bit of prosimians and anthropoids, and certain characteristics of their own. From prosimians they have retained the grooming claw that is a large claw on the second toe used to groom and the fusion of their mandible at the midline to form one bone by cartilage. But what tarsiers lack is the rhinarium that lemurs and lorises have, making them closer to anthropoids. Because of this trait there is much controversy as to what suborder tarsiers belong to, being stuck in between both. A characteristic that tarsiers have but is found in no other primate is the ability rotate their head 180%, this is to compensate for the fact that they are unable to move their eyes within their sockets. Their eyes are of great size compared to their body size, each eye is actually about the same size as their brain. I was not able to observe any tarsiers at the zoo, but I would have loved to because of their very interesting qualities.
Grade III- The Monkeys is part of the anthropoids suborder. Monkeys are broken down into two particular groups the New World monkeys and the Old World monkeys. There are about 195 monkey species that account for 85% of all primates. There are also new discoveries being made, so the status of some monkeys is currently in uncertainty. New World monkeys are monkeys that are only found in the new world, hence the name, that inhabit both continents. They are thought to have gotten to the New World by way of South America as a result of “rafting” on portions of land that broke away from Africa millions of years ago. They are found from the forested areas of southern Mexico to those of South America. The roughly 70 New World monkeys range in size and diet. Something quite interesting from these monkeys is that they are almost always on trees, living their whole lives swinging and climbing from tree to tree; this is so that some never come to the ground. These New World monkeys are all diurnal except the owl monkey that is of nocturnal activity. New World monkeys are known as platyrrhine meaning flat nose, this is because they have outward-facing noses and broad noses; this feature differentiates them from their Old World brothers.
Although in recent years there has been much controversy about what families these New World monkeys should be put in because of fossil evidence, the book continues to divide them in the traditional way of two families. These two families are Callitrichidae and Cebidae. The Callitrichidae family includes marmosets and tamarins, while Cebidae includes all of the remaining monkeys in the Americas. Some primatologists have argued that the marmosets and the tamarins should be added to the family Cebidae and that the family Callitrichidae be abolished. This change would also create a new family called Atelidae; this new family would include spider