Online Custom «Chimpanzees and Australopithecus Afarensis Comparative Research» Essay Sample

Australopithecus afarensis (“southern ape of Afar”), the first known “ape”, probably appeared about 4 million years ago. He was named after the findings of the so-called northern triangle of the Afar in Ethiopia, though Afar Australopithecus fossils were also found in Omo (Ethiopia) and Laetoli (Tanzania). This creature resembled a small chimpanzee that walked erect. It is said to be one of the first hominids and is hardly distinguished from an ape. Therefore, there is a necessity to find characteristic features that distinguish Australopithecus from a modern chimpanzee.

Body size of A. afarensis is extremely varied. The difference reflects, apparently, sexual dimorphism, which is equal to that of gorillas and orangutans, and greater than that of chimpanzees. The height of small specie could be just above the meter, while the large one could be more than meter and a half; weight ranged, respectively, from about 30 to 45 kg, up to, perhaps, 55 kg. In comparison, chimpanzees can be up to 170 cm tall and can weight up to 70kg, i.e., they are a little larger than Australopithecus (Smith et al., 2013).

The skull of A. afarensis is rather small. It has volume of approximately 380-430 cm³, which is slightly larger than that of a chimpanzee. A. afarensis’ skull has a low, sloping forehead and protuberant brow ridge. Temporal line of the frontal bone forms a low sagittal crest. Back of the head is refracted, and occipital crest is well-marked (Stern, 2000). Base of the skull is bent very slightly. In occipital zone, the skull of A. afarensis is lower and more extended at the bottom than in chimpanzee, which is a more primitive one. Endocranium of Australopithecus looks very similar to that of chimpanzee, but it does not have the print lunate (“monkey”) furrows (Stern, 2000). Parietal and temporal association areas are increased, which, undoubtedly, distinguishes A. afarensis from chimpanzees and makes them look like human beings.

Characteristic feature of the teeth structure of A. afarensis is a large size of incisive teeth. Their upper canines strongly protrude above the adjacent teeth, their size and morphology is intermediate between a chimpanzee’s and human one, approximating yet to the last. Their fangs are pointed at the top, their roots are laid back. Dental arcade is U-shaped and the teeth structure is rather primitive. However, canine teeth are much smaller than those of a chimpanzee. In addition, there is no CP₃ honing in these species (Stanford, Allen, & Anton, 2010). Therefore, the teeth of A. afarensis more resemble human one than of a chimpanzee.

The complex structure of the distal radius indicates that the A. afarensis, or their immediate ancestors, could walk on the phalanges of the fingers. Characteristic structure of the pelvis of Australopithecus afarensis is very different from a high-narrowed pelvis of chimpanzees. Their pelvis is very wide and short (Stanford, Allen, & Anton, 2010). Femur is angled towards knees to keep it under the center of gravity. Apparently, ability to walk bipedally in A. afarensis had developed much since their tibia is constructed to bear large weight and a big toe is in line with others. This eliminates the seizing ability of muscular cramps, which is largely different from that of chimpanzee. Postcranial skeleton is similar to that of a chimpanzee since thorax is more of funnel type similar to apes, indicating that A. afarensis has a vegetable diet (Stanford, Allen, & Anton, 2010).

In general, hands of A. afarensis are somewhat elongated relative to the legs; the corresponding index has a value intermediate between the one of a chimpanzee and a modern man. Also, the size of the feet is similar to that of chimpanzees. Australopithecus had rather small pollex and large hallux; they had curved phalanges, which probably served for climbing the trees while escaping from predators. Therefore, some scientists assume that despite their bipedalism, they easily could climb the trees like chimpanzees. Such a finger structure is similar to the one of a chimpanzee; the only distinction is that chimpanzees have small membrane developed between the toes of the hind limbs.

Australopithecus lived in groups of a few individuals, and, apparently, constantly roamed around the expanses of Africa in search of food (Smith et al., 2013). More likely, they lived in families consisting of one male, who was the head of a family, and several females, who obeyed. Such social structure is rather weak in comparison to that of chimpanzees, who live in organized social groups with an alpha male in charge (Smith et al., 2013). Family groups of A. afarensis were engaged in gathering plant foods, which included hard, solid or fibrous seeds and fruits. This diet is the same to that of the modern chimpanzees. Some individual specimens may have produced crude tools out of wood and stone to separate the meat from the bones of animals killed by predators. A. afarensis lived in a wide range of conditions - from rainforests to dry savannas. In contrast, chimpanzees primarily inhabit wood areas in order to hide in trees for the night (Smith et al., 2013). For the most part, A. afarensis inhabited relatively open spaces.

Overall, the morphological characteristics and socio-cultural implications of Australopithecus afarensis indicate that these ancient species had some distinctive features being similar to that of a chimpanzee. However, the large part of physical characteristics, such as the structure of bones and skull, are different. Moreover, one can notice that a physical structure of the body of Australopithecus is similar to the human one. Therefore, the conclusion is that Australopithecus can be considered as common ancestor of both a human being and a chimpanzee.