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Evolution a complicated process
Similarities between humans and chimpanzees
Similarities between humans and chimpanzees
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Charles Darwin founded the theory of evolution by natural selection, which according to this principle defines; biological characteristics enhance survival increase in frequency from generation to generation (Larsen et al. 22). These individuals are inclined to produce more sustainable offspring to pass their genes to, meaning that some individuals are more reproductively fruitful than others. Natural selection requires variation in a species, which can result by gene flow, mutation, or genetic drift & also involves environmental stresses such as climate change. These result as the evolutionary means of how certain traits can be selected. Eventually, traits that give individuals certain advantages, such as bipedalism in hominids, will be selected …show more content…
The short, broad modern human pelvis has evolved from a taller, narrower pelvis of the chimpanzee or gorilla. Lucy's pelvis, the first Australopithecus Afarensis skeleton to be recovered, differed from a chimpanzee’s pelvis. In the structure of the hipbones, a chimpanzee’s are facing straight forward, whereas in Lucy’s the pelvis was much more human like as it was small & wide but it required the modifications that enable today’s hominids to walk with a striding posture (Becoming Human: Part 1). Natural selection created a human pelvis giving a saddle like support system for bipedal locomotion. The iliac bones construct the saddle feature around the human waist, while in chimpanzees the bones lie flatly posteriorly. This assisted chimpanzees because important climbing muscles attach to the iliac blade. In humans the curved iliac bones provide stability & support for the weight of standing upright & walking; this shape allows the attachment of the big gluteal muscles which are also used to support upright posture …show more content…
The human foot is transverse & arched, while the chimpanzee foot lacks these arches due to the fact that their feet are flat. This distinct feature gives human’s increased leverage as the body pushes forward & serves as a shock absorber when the feet make contact with the ground during walking & running (Larsen et al. 232). Also, humans have fully extendable legs due to a lockable knee joint & a natural knock-kneed stance which differs from the chimpanzee bow-legged stance. Additionally, the human femur attaches at an inward angle to the pelvis which makes the knees lie underneath the center of gravity, the pelvis. This inward angle of the femur provides stability in standing, walking & running (Lecture). As the climate was drying in East Africa, sources of food, such as fruit trees, were growing farther apart & hominids would have to walk farther & farther to gather food (Becoming Human: Part 1). As a result of this anatomical variance, humans can stand upright for long periods of time without much energy outlay. Whereas in quadrupeds, upright posture takes up much more energy because their legs need to stay flexed, requiring the use of more muscles than a human to keep their balance, which is where the bow-legged stance comes into
Irregular bones are bones of various shapes that do not fall into these other categories. The hip bones, the vertebrae, and many of the bones of the skull are example.
Bipedalism is a form of locomotion that is on two feet and is the one factor that separates humans from other forms of hominoids. The first bipeds are believed to have lived in Africa between 5 and 8 million years ago. (Haviland et al. 2011, pg. 78). The evolution to bipedalism resulted in various anatomical changes. To be able to balance on two legs, the skull must be centered over the spinal column. As bipeds evolved, the foramen magnum, the opening at the base of skull for the spinal column, moved from the back of the skull to the center. The spinal column also evolved from a continuous curve to a spine with four concave and convex curves. (Haviland et al. 2011, pgs. 79, 80). Another change was the widening of the pelvis which gives a wider plateau for more balance when walking on two legs.
Ardi was the first primate to walk on two and who had begun the process for all other primates to walk on two. Ardi was four feet tall as was able to climb in trees but was able to walk upright while on the ground. Ardi has many similarities to humans, for example, Ardi’s top pelvic looked human, but the lower half is longer which meant it was useful for climbing. She was able to grasp with her toes and feet and her hands had long fingers and smaller palm like humans.
Lemelin, Pierre, Daniel Schmitt, and Matt Cartmill. “Footfall Patterns and Interlimb Co-Ordination in Opossums (Family Didelphidae): Evidence for the Evolution of Diagonal-Sequence Walking Gaits in Primates.” Journal of Zoology 260.4 (2003): 423–429.
There is great debate over the concept of primate evolution. Some research supports the idea that evolution occurred linearly as a continuum while other research supports the idea that fossils found to date should be separated into individual species. Through morphological, and geological evidence this paper explores this topic and provides concise arguments to further develop the understanding of human primate evolution.
Bipedalism is anatomically important because it now demonstrates to us modern day humans the cycle of how we came to be. This skill was vital to human evolution because it differentiates early hominins from apes. By being able to walk further distances, they brought them to a diverse new diet that enabled their brains to get bigger. Bipedal animals usually walk greater distances because less energy is needed with their longer strides. The stone stools show evidence of abstract thinking and it shows the early hominins adapting and using their environment to survive, which is a skill that we as modern humans have surpassed.
1.9 million years ago, Homo Habilis of East Africa had evolved into an entirely new species known as Homo erectus. Homo erectus directly translates to "Upright man" and for good reason. One of largest anatomical advancements of Homo erectus was their arm and leg bones which were very similar in shape and proportions to that of modern day humans. "Their legs would have made Homo erectus efficient long distance runners like modern humans."(Dennis). Along with their longer more developed legs, Homo erectus's leg were also hairless which allowed them to evaporate sweat and thus be more efficient at not overheating. This advantage allowed Homo erectus to chase down four legged mammals to the point of heat exhaustion and thus drastically increase the efficiency their hunting tactics. Another change in the legs of Homo erectus was their slightly more narrow pelvises. This forced the size of a child’s head to be smaller at birth and undergo most of its development during childhood. (Dennis)
The members of the Homo genus possess a combination of unique features that distinguish them from other related species. At the time that each respective species was alive, they were able to walk upright on two legs, use their large brains for the benefit of their species, and could thrive in many geographically and climatically diverse areas of the world. One of the most mysterious quandaries in science is how the lineage of the Homo genus became so different from their primate relatives. Bipedalism, brain size, and location diversity all have a common link that may explain this difference – dietary evolution allowed humans to adapt to their surroundings, and in turn, become a more advanced species. The Homo diet evolved in relation to food availability and nutritional necessity. With the ability to maintain a proper diet, the species of the Homo genus were able to flourish and advance toward the development of modern Homo sapiens.
With the studies that Charles Darwin obtained he published his first work, “The Origin of Species.” In this book he explained how for millions of years animals, and plants have evolved to better help their existence. Darwin reasoned that these living things had gradually changed over time to help themselves. The changes that he found seemed to have been during the process of reproduction. The traits which would help them survive became a dominant trait, while the weaker traits became recessive. A good example of what Darwin was trying to explain is shown in giraffes. Long-necked giraffes could reach the food on the trees, while the short-necked giraffes couldn’t. Since long necks helped the giraffes eat, short-necked giraffes died off from hunger. Because of this long-necks became a dominant trait in giraffes. This is what Charles Darwin would later call natural selection.
The axial skeleton is the central point of the body; movement evolves around this axis. It consists of 80 bones, there are 29 bones altogether in the cranium as well as 24 bones in the ribs and 1 as the sternum. 26 bones as the vertebral column, 24 being the vertebrae as well as the sacrum and the coccyx. The functions of the axial skeleton are that it helps to support and protect the organs as well as creating a surface of attachment
Some paleontologist considers walking upright on two legs is the characteristic that defines humankind. There could be some truth into that statement but I believe that our higher brain function or big brain is the trait that defines humanity. So, among the living primates, just us humans are bipedal. Facultative bipedalism is a time where an animal stands on two legs for a limited amount of time. That is used for survival, as opposed to hominids where they use it primarily or exclusively. For instance, animals could still be on two legs to keep away from a predator, or to reach food that is in a high area. Numerous creatures use facultative bipedalism. Bipedalism is significantly more extraordinary this is what humanity uses. Bipedalism isolated
The characters in the caveman walked bipedally all through the movie without any clips of quadrupedalism. There is no evidence or scientific proof to back up that bipedalism or walking upright existed one zillion years ago just as the film portrayed. They got this wrong based on what I have learned in my Anthropology class that bipedalism does not exist not until of recent.
Mountain Gorillas are known to walk on two arms and two legs. This is different than being a quadruped because they do not possess four feet since there is a physiological difference between their arms and legs: that being that their arms are longer. They do, however, possess the capability to run on their two legs for short distances.
Transportation has vastly changed since the beginning of man. We started with nothing but our feet and the ground below. Quadrupedalism was our ancestor’s first step moving around on all four limbs held huge disadvantages to daily life. Moving all four required large amounts of energy to be spent on movement and it was rather slow. Our spines were bent at an odd angle from where they are today. Also being on all four’s meant a larger area exposed for su...
One of the most important and pivotal physical and biological adaptations that separate humans from other mammals is habitual bipedalism. According to Darwin, as restated by Daniel Lieberman, “It was bipedalism rather than big brains, language, or tool use that first set th...