Chimpanzees are the closest living relative to humans with only a genetic difference of 1.2 %. And the Australopithecus afarensis shows a clear mosaic of human-like and ape-like anatomical structures. Here in this paper I would compare and contrast the physical characteristics and social behaviors of chimpanzees and Au. afarensis. Through investigating the relationship between chimpanzees and Au. afarensis it may give us a better picture of how and why humans evolved to what we are today.
The average male Au afarensis weighs about 92 lbs and females about 64 lbs. (National Museum of Natural History) For chimpanzees males could weigh up to 150 lbs and 10-15% heavier than females. Au. afarensis has a cranial capacity of 450cc and the Chimpanzees …show more content…
afarensis had adaptions to their anatomical stucture to support bipedal locomotion. The foramen magnum of the Au. afarensis was located closer to the base of the cranium than the chimpanzees which located at the rear end. The head of the Au. afarensis was then supported by a S-shaped spine to bring the center of gravity closer to the hips, over the two feet, so that it doesn’t fall over. A chimpanzee’s C-shaped spine causes its body to fall forward and therefore they couldn’t walk well bipedally. The pelvis of Au. afarensis transformed to a shorter appearance with short, broad and bowl-shaped ilium blades compared to those of chimpanzees. The basin-shaped pelvis helps to support abdominal organs when walking upright. The broader ilium also pulls the hip joint closer to the sacrum which gives better balance. Like the humans, the Au. afarensis had angled femur that places the foot under the center of gravity. The femur of chimpanzees on the other hand are straight down. The patellar groove on the Au. afarensis was found to be deeper to avoid the patella dislocating outwards. The end of the femur and the tip of the tibia was also enlarged to bear more weight. The hallux of the Au. afarensis had extended in line with the other toes and enlarged while chimpanzees had opposed hallux. (Stanford et al., 2013) According to researchers the Au. afarensis had arches in the feet, the arch acts as a shock absorbant and provides a stiff platform for bipedal walking. (Ward, …show more content…
They follow the fission-fusion mating system where they don’t stay in stable units. Subgroups are formed within the community when performing different activities. The community would occupy a territory then the males would patrol around the boundaries regularly and kill any intruding chimpanzees unless it’s a sexually receptive female chimpanzee which they would bring back to the community. Chimpanzees live in male-philopatric communities, where the male would stay in their birth communites for their whole lives. Once female chimpanzees reach maturity, they would visit other communities and may settle down there. Au. afarensis possibly lived in groups too. They probably follow a polygynous mating strategy since they are very sexually dimorphic. Tool use behavior were found in both Au. afarensis and chimpanzees. Some chimpanzees would use stones to crack open hard-shelled nuts. There is also some degree of hunting behavior observed in chimpanzees. (Stanford et al., 2013) Evidence has also been found by archaeologist that Au. afarensis had use stone tools and consuming large mammals. Cut marks and percussion marks are found on large mammal bones suggesting the use of stone tools. (California Academy of Sciences,
The average male Au afarensis weighs about 92 lbs and females about 64 lbs. (National Museum of Natural History) For chimpanzees males could weigh up to 150 lbs and 10-15% heavier than females. Au. afarensis has a cranial capacity of 450cc and the Chimpanzees …show more content…
afarensis had adaptions to their anatomical stucture to support bipedal locomotion. The foramen magnum of the Au. afarensis was located closer to the base of the cranium than the chimpanzees which located at the rear end. The head of the Au. afarensis was then supported by a S-shaped spine to bring the center of gravity closer to the hips, over the two feet, so that it doesn’t fall over. A chimpanzee’s C-shaped spine causes its body to fall forward and therefore they couldn’t walk well bipedally. The pelvis of Au. afarensis transformed to a shorter appearance with short, broad and bowl-shaped ilium blades compared to those of chimpanzees. The basin-shaped pelvis helps to support abdominal organs when walking upright. The broader ilium also pulls the hip joint closer to the sacrum which gives better balance. Like the humans, the Au. afarensis had angled femur that places the foot under the center of gravity. The femur of chimpanzees on the other hand are straight down. The patellar groove on the Au. afarensis was found to be deeper to avoid the patella dislocating outwards. The end of the femur and the tip of the tibia was also enlarged to bear more weight. The hallux of the Au. afarensis had extended in line with the other toes and enlarged while chimpanzees had opposed hallux. (Stanford et al., 2013) According to researchers the Au. afarensis had arches in the feet, the arch acts as a shock absorbant and provides a stiff platform for bipedal walking. (Ward, …show more content…
They follow the fission-fusion mating system where they don’t stay in stable units. Subgroups are formed within the community when performing different activities. The community would occupy a territory then the males would patrol around the boundaries regularly and kill any intruding chimpanzees unless it’s a sexually receptive female chimpanzee which they would bring back to the community. Chimpanzees live in male-philopatric communities, where the male would stay in their birth communites for their whole lives. Once female chimpanzees reach maturity, they would visit other communities and may settle down there. Au. afarensis possibly lived in groups too. They probably follow a polygynous mating strategy since they are very sexually dimorphic. Tool use behavior were found in both Au. afarensis and chimpanzees. Some chimpanzees would use stones to crack open hard-shelled nuts. There is also some degree of hunting behavior observed in chimpanzees. (Stanford et al., 2013) Evidence has also been found by archaeologist that Au. afarensis had use stone tools and consuming large mammals. Cut marks and percussion marks are found on large mammal bones suggesting the use of stone tools. (California Academy of Sciences,