...Primate Bipedalism Andrez Guillen Anthropology 301-02 No other form of locomotion has been as dominant over the years as bipedalism. We humans take this form of stance for granted, not fully understanding its importance. Compared to other stances, such as quadrupedalism, bipedalism serves us a better in many areas. Here we will look at the the advantages of walking upright Many theories have been said about how early hominids began evolving their stance from quadrupedal to bipedal. Charles Darwin, for example, claimed that we stood up to free our hands for tool making (Douglas 2012). Others say that our evolution began up in the trees where we see other primates, such as orangutans, walk bipedal to get fruit. Another is the idea of “carrying,” here we see other primates go from a qudrapedal position to a bipedal position when carrying something of importance (offspring, food, tool). All of these theories have something in common, each shows how advantageous it is to be bipedal and it could be said that these advantages helped our ancestors survive. One possible explanation for the development of bipedalism, is our search for food. Here the argument is that 5 million years ago, fruit trees in Africa were spreading further and further apart from one another. Hominids would have to walk with their young to find fruit trees, this caused a great deal of discomfort for the females, so the solution was to have the monogamous male do the travel while the female stayed put...
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...Bipedalism is form of locomotion such as walking and running on two legs. It isn't uncommon to see animals walking on two legs but it isn't a common practice as their usual means of locomotion. Many including gorillas and chimpanzees assume bipedalism on a temporary basis in order to act on a particular function or form of locomotion. Bipedalism has been discussed and reviewed many times and most explanation target a single cause. Like Lucy having having such a small stature standing at only 31/2 feet tall, the challenge she would have venturing out in the forest would be dangerous in the world of the grasslands. Standing through the grass would announce there presence to present predators in the area. Being slow, clumsy runners, the early hominids would have quickly fallen prey. Lacking the ability to fall back onto all fours and outrun the carnivores would have signaled the end of human evolution.There also anatomical changes that are associated with walking bipedally like the limbs and pelvis having to change.The pelvis had to be able to hold the weight of the whole body. The knees had to lock. There was also a difference in feet, and brain grew. The hind legs had to become stronger to carry all the weight....
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...Bipedalism Through the use of experimental studies, it can be concluded that locomotion in human beings showed that the evolution of bipedalism was more an intricate transformation rather than a simple transition from quadrapedalism. These studies also suggested that bipedalism first came about from an arboreal ancestor, rather than a terrestrial, land ancestor. 1. A 2007 study suggests that energy was the primary reason why bipedalism (walking on two legs) arose from quadrapedalism (walking on four legs or ‘knuckle walking’). Because of the reduction in energy expended from walking on two legs, it is suggested that this provided evolutionary advantages, and allowed chimpanzees to better accommodate to the varying terrestrial phenomena. It’s concluded that the smaller the chimpanzees steps, the greater the energy it uses. From the data gathered in the report it can be assumed that energy consumption in chimpanzees played a significant role in the transition from quadrapedalism to bipedalism. The findings allow researchers to examine adaptations such as the lengthening of limbs that may have contributed to the evolution of bipedalism in chimpanzees. 2. A second study from the University of Illinois which involved the study of biomechanics, that is, locomotion, joint movement and stress in bones and limbs assumes a dissimilar perspective to the notion put forward above. The hypothesis that is reached by a team of paleoanthropologists is that the evolution of upright...
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...While humans and primates are related in many ways, there are distinct characteristics for hominids. The most unique characteristic difference that separates hominids and non-human primates is bipedalism. While hominids walk on two feet, non-human primates are quadrupedal, using all fours to get around. Multiple experiments were conducted to identify between the advantages and disadvantages of being bipedal. The first experiment involved observing human and non-human primates and their difference in methods of locomotion. All of the people observed used two feet to get around. At the same time they all made use of their hands whether it was the biker steering his bicycle or the multiple people on holding their cell phones. On the other hand, the video of the gorilla demonstrated quadrupedalism. While the gorilla was able to go from walking slowly to running on all fours, it was unable to use its hands for other tasks. The gorilla demonstrated knuckle walking because they have many wrist and forearm features that allow them to do so (Hirji, 2009). Through observations in the video as well as at the zoo, it was easy to see that non-human primates do not have a skeletal structure that is specialized in bipedal locomotion. All in all bipedalism is necessary in order to carry objects and complete other tasks while moving. Therefore, the human body was able to evolve to compensate for bipedal locomotion. The next station involved putting the observations from station one into...
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...thing one can notice about the human body structure, from our vertical curved spine to the relative length of our legs, is that we are meant to be bipedal. Bipedalism is often mentioned as a factor that defines us as humans. Gordon Hewes (1961) stated that “man’s upright posture and bipedal gait have been justly considered outstanding features of human nature…” (p. 687). There’s no denying that bipedalism is important to us now, but the concept of bipedalism brings about the issue of why. Why did our early ancestors...
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...the male would be away for a long duration due to his search for food, monogamy was passed in order to keep his woman not to be involved with other men. His responsibility would mean, he would have to provide for his woman and carry the food. The man was able to carry it because his hands were free and walking bipedally instead of walking quadrupedally. On the Lookout Theory * Original Name: Vigilance Hypothesis * Theory by: Raymond Dart * “Raymond Dart's vigilance hypothesis described a situation where early hominids who stood upright would have the benefit of seeing over tall savanna grass (Dart 1926). This would allow them to see predators from a distance. Additionally, their other sense organs would be elevated with bipedalism.” * This hypothesis/theory states that early hominids stood upright in order to have a better view of what’s over the tall savanna grass and would allow them to see possible predators coming from a distance. As one stands upright over the grass, the upper body will be elevated and only 2 limbs will support you from the ground....
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... When moving in a variety of environments, quadrupedal mammals typically exhibit a form of lateral gait sequence, where the movement of a hind-limb is coupled with the movement of the fore-limb on the same side of the body (Lemelin, et. al: 2003). In contrast, all quadrupedal primates, with varying degrees of success, are able to move throughout their environment using a diagonal sequence gait (Lemelin, et. al: 2003; Schmidt: 2005; Schmidt, et. al: 2006). Here, locomotion is marked by the simultaneous motion of adverse fore-limb reaching and hind-limb pushing (Schmidt: 2005; Schmidt, et. al: 2006) (see Appendix V). In order for this particular gait sequence to be effective in a number of environments, both terrestrial and arboreal quadrupedal primates require the ability to generate sufficient power in the hind-limbs that pushes the body forward, while maintaining over-all stability. Moreover, to create the fore-limb motion associated with a diagonal gait, it is expected that terrestrial quadrupeds primarily depend upon humeral reduction (Whitehead and Larson: 1994), which refers to the motion of moving the body over the shoulder and fore-limbs (Larson and Stern: 2007). In contrast, arboreal primates rely upon increased scapular and shoulder joint mobility in order to achieve the reaching and pulling motion necessary for locomotion (Larson and Stern: 2007; Schmidt: 2005). The difference in the movement of the shoulder is due, in part, to the relatively upright and lowered...
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... The traits of the mystery mandible include small anterior/ large posterior teeth, a thick mandibular corpus, parabolic dental arcade, presence of molarized premolars, presence (and very thick) simian shelf, absence of chin, and absence of retromolar space. In accordance, these are all distinguishing traits for Australopitecus Boisei. The Ardipithecus ramidus is distinctly not the mystery mandible because it lacks megadontia and withholds a thinner enamel than that of the mystery mandible . Ar. ramidus thin enamel is one associated with a ripe-fruit frugivory. In this way, one can conclude that Ar. ramidus avoided tough diet foods, as they did not have the heavy chewing specializations (thick mandibular corpus/ megadontia) present in the features associated with that of the mystery mandible. The robust Australopithecines ( Au. boisei and Au. robustus) possessed greatly enlarged cheek teeth and very thick enamel when compared with the ‘gracile’ Australopithecines (Au. africanus ). This increased enamel thickness is directly related to their distinct dietary adaptation. In this way, the masseter muscles and temporalis muscles (zygomatic arch) were distinctly larger and their mandible was much more robust than that of the gracile Au. africanus. Such features indicate that the robust australopithecines were consuming a hard food diet that included nuts and seeds. For this reason, since the mystery mandible also possessed an extremely thick mandible with small anterior and large...
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...Early Hominin Species Hominin is used to refer to members consisted in the family of humans. These species are thought to have existed over 30 or 40 million years ago. An example of one of the early species is Australopithecus afarensis. A. afarensis is believed to have existed between 3.7-3.0 million years ago in east Africa. Their skeleton was transitional from the earlier species of ape since their face was apelike with a low forehead, a flat nose, a bony ridge on the eyes and had no chin. Their jaws were protruding and they had large back teeth. Its brain size ranged between 390 and 515cc. Their skull looked similar to that of the chimpanzee but their teeth looked more like those of humans. Their canine teeth were smaller and blunt than those of apes but larger and pointed than those of humans. Their molar teeth were large and had thick enamel. This suggests that they ate hard foods that required a lot of chewing. The shape of the jaw is between the parabolic shape of humans and the rectangular shape of apes. Their pelvis was bowl shaped which indicate that they were bipedal. Their legs were shorter and they were more adapted to walking than running (Leakey 1994). Their first toe was in line with the other toes (Ward, 2002; Harcourt-Smith and Aiello, 2004). Their forearm, toes and fingers were long and curved which suggests that they used trees regularly to forage and to refuge from predators at night. Their body size was small. Males weighed about 40kgs and...
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... Assignment 2 Abdulaziz alkharfi 15. Is a form of type locomotion where an organism walks by means of its two rear limbs or legs. 16.This feature indicates that the head of Sahelanthropus was on an uppper body, probably working with walking on two legs. Because if we set the skull on ape body the eye will be toward the ground which make no sense. 17.Hominids evolved to walk upright in response to climate change. As forest getting smaller, hominid ancestors found themselves descending from the trees to walk across stretches of grassland that separated forest areas. The most efficient way is to walk on the ground was bipedally. Their food supplies were becoming more widely dispersed. and the forest was changing to more open grassland, with more distance between food resources. If our ape ancestors had to roam farther to find food, and doing so on two legs saved energy, then those who moved across the ground more economically gained an advantage. 18.The older layers of the earth are exposed here, so fossils of all ages can be found. The many layers of sediment show the changes that occurred in the environment as the layers of dirt built up over time.. Ash layers from nearby volcanic eruptions can be dated, providing a time line for changes in climate, plants and animals, and the ways of life of early humans. Selam’s skull was CT scanned and it was this method that allowed her sex and age at death to be determined. The clue came from white volcanic ash that dated 3.4...
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...fully upright on two legs, known as bipedalism. These early humans showed prognathism, the jutting forward of the lower face and jaw area, they also had pointed canine teeth like that of apes. They had the brain size of chimps, about 480 ml, and weighed about 105 pounds on average. They also had long and heavily muscled arms and relatively shorter legs. These early hominins looked like apes, except they walked bipedally. Microscopic analyses of their teeth indicate a mixed vegetable diet of fruits and leaves. The fossil skeleton of ‘Lucy’ is an example of Australopithecus. The adaptive themes of bipedalism, large brains, complex social organizations, and tool technology were established during this period. The first hominin feature to evolve was bipedalism, millions of years before the development of our big brains. The evolution of bipedalism with the retention of long, strong, and powerful shoulders and arms was an adaptation to living in an environment of both arboreal (forested) and terrestrial (plains) areas, giving our early ancestors great adaptive flexibility. Bipedalism served various important functions. It freed the forelimbs to carry things such as food or offspring and it aided early hominins’ ability to find food and see danger by elevating the head up. The vertical orientation helped to cool the body by exposing a smaller area to the sun and placing more of the body above ground to catch cooling air currents. Bipedalism was...
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...species on earth. This shows that humans are apart from anything else that god has put forth on earth. People may ask, what makes us human? What are things that we have done or can do, that have got us to this point? Many Anthropologists have been thinking of answers to this question and have come up with a number of conclusions, but the 3 most defining characteristics human possess are bipedalism, communication through different forms of language, and lastly human’s ability of realization of belonging. Firstly, bipedalism is a natural trait humans have acquired which allows them to walk on two rear limbs in a vertical posture, with frontal limbs free. Importantly, bipedalism is a trait that has immensely contributed in advancing humans’ abilities and has allowed them to accomplish both simple and complicated tasks, furthermore advancing their repertoire compared to other mammals. It is estimated that humans in general started to become bipedal around 3.6 million years ago. Humans’ first try to attempt standing on their own two legs is in their late infancy stages (7-12 months). The act of bipedalism is crucial to a human’s development as it frees up our hands thus improving our ability to easily do things like eat while walking, make use of tools, and avoid predatory attack along with many other tasks. In the early stages of human development, in order to come up with food humans would need to hunt, which would be performed by throwing hand made spears at their prey and...
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...Haydee Munoz 01063896 ANT2033 15- April-2010 Physioanatomical Analysis of Australopithecus Afarensis The first Australopithecus afarensis was found in 1974 by Don Johanson at Hadar in Ethiopia, Africa, and dates from about 3.9 to 3 million years ago. The very complete fossil is thought to be a female skeleton and it is called “Lucy” after a Beatles song. Because the skeleton is 40 percent complete, it facilitates a more accurate analysis in a broader sense. When comparing A. afarensis to a chimpanzee, a species with many traits that for hominins are considered primitive, and a modern human, it is concluded that the subject is very primitive, because it shows few developed traits. The Lucy skeleton is female and it is approximately 3 or 4 feet tall, while other A. afarensis male fossils have been found that are about 5 feet tall. While male chimpanzees average height is 4 feet tall and female average height is 3 feet tall, the male human height average is 5 feet 9 inches and the female average is 5 feet 3 inches. Therefore, like chimpanzees, Australopithecus afarensis has smaller body size than the modern human. Also, A. afarensis is sexually dimorphic, which is a trait that is common for attraction and reproduction among apes, while humans are not very different in body size among sexes. One of the most characteristic derived traits of modern humans is brain size. Modern humans have between 1150 to 1750 cm3, chimpanzees have 285 to 500 cm3, and A. afarensis...
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...mammals. Primates have excellent visions. I have forward-facing eyes that sit close together. By it being shaped this way it allows me judge the distance of objects their size and height and to see things in three dimension. This lets me see how far a soccer ball it is its hight and size and at what pace the soccer ball is coming at me. My eyes are both able to look at things from different angles but bring together one image. Depth perception is important because it keeps me from bumping into things and being able to tell at what pace things are coming at. A major thing that helps me do everything in my every day life is being dexterous because having a power grip and being bipedalism helps in being able to hold things and to use them as tool for example being able to write is given to the power grip. Bipedalism gives me the availability to stand up right and walk on two feet being able to play sports is one example. Another one would be my teeth it allows me to eat food by using my canines that are much smaller than other mammals this allows be to be able to chew my food better and I am able to eat a variety of food not just one specific category. Every primate mammal has a parental investment it is not all the same but with me my parents growing up teach me from right and wrong I grow up doing what they do because I watch them do it and i think it is the right way. This leads to how I socially express myself I am able to express myself tell when I am mad angry and sad. This also...
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...Many different theories of human evolution cause people to think one way or another on how humans came about. The process of natural selection can easily be known as one of the most popular ideas that have dominated the beliefs of many people. Having a common ancestor is the act of descent with modification. There are many different species that are classified into groups depending on how they adapt. These groups of mammals have been given certain names depending on the lifestyle in which the species are adapted. These may range from living in water to being airborne, burrowing in the ground, open grassland, predation, and even trees. Cetaceans are the marine mammals. Chiroptera are the mammals that have the ability to fly, mostly known as the bat. Rodentia are the mammals known as the rodents. Ungulata are the mammals that are known as being hoofed. Carnivora are the mammals that are predators. Lastly, the primates are the mammals that are arboreal or live in trees.The common ancestor for humans happens to be those who adapted to living in trees. Humans are known as mammals. They have an adaptation that makes them survive called the mammary gland. This is an organ that produces milk to breast feed offspring. The word mammal in fact comes from mammary which is interesting enough why the young usually learn their first word as "mamma." All mammals happen to have a chemical that leads to the relationship between a mother and child. This hormone is called oxytocin. They are also...
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