Gif animation by Andrew Mills
from E. Muybridge"s (1913)
The Human Figure in Motion
Week 6: Genus Homo Part I
This lab focuses on the earliest two groups in the Genus Homo and provides some hands on experience with the skeletal material discussed in lecture. By the end of the lab you should be able to determine the identity of each specimen using the characteristic features discussed in lecture and lab. You should also notice how specific features change from the earliest to more recent species. For the first five stations, describe each feature and then determine the identity of the specimen. The final station of the lab introduces stone tools.OBSERVE THE FOLLOWING FOR EACH OF THE FIRST 5 STATIONS:
Cranial capacity
Size of the Brow Ridge
Degree of post-orbital constriction
Shape of the cranium: cranial vault
Shape of the cranium: Height of the widest point
Size of the Jaw: Relative ro jaw of AMH's
Size of molars: compared to incisors
Identity of the specimen
WEB CREDIT: Many of the SPECIES DESCRIPTIONS from Week Six, Hominid skullduggery, and Week Eight come from Jim Foley's outstandingThe Talk.Origins website.
Homo habilis and Australopithicus africanus
Homo habilis
H. habilis, "handy man", was so called because of evidence of tools found with him. Habilis existed between 2.4 and 1.5 million years ago. It is very similar to australopithecines in many ways. The face is still primitive, but it projects less than in A. africanus. The back teeth are smaller, but still considerably larger than in modern humans. The average brain size, at 650 cc, is considerably larger than in australopithecines. Brain size varies between 500 and 800 cc, overlapping the australopithecines at the low end and H. erectus at the high end. The brain shape is also more humanlike. The bulge of Broca's area, essential for speech, is visible in one habilis brain cast, and indicates it was probably capable of rudimentary speech. Habilis is thought to have been about 127 cm (5'0") tall, and about 45 kg (100 lb) in weight, although females may have been smaller.
Habilis has been a controversial species. Some scientists have not accepted it, believing that all habilis specimens should be assigned to either the australopithecines or Homo erectus. Many now believe that habilis combines specimens from at least two different Homo species.Homo erectus (Java)
Homo erectus (China) & H.sapiens (for comparison)
There are "regional varieties" of Homo erectus e.g. Africa, Asia, Java
Homo erectus
H. erectus existed between 1.8 million and 300,000 years ago. Like habilis, the face has protruding jaws with large molars, no chin, thick brow ridges, and a long low skull, with a brain size varying between 750 and 1225 cc. Early erectus specimens average about 900 cc, while late ones have an average of about 1100 cc (Leakey, 1994). Some Asian erectus skulls have a sagittal crest. The skeleton is more robust than those of modern humans, implying greater strength. Body proportions vary; the Turkana Boy is tall and slender, like modern humans from the same area, while the few limb bones found of Peking Man indicate a shorter, sturdier build. Study of the Turkana Boy skeleton indicates that erectus may have been more efficient at walking than modern humans, whose skeletons have had to adapt to allow for the birth of larger-brained infants (Willis, 1989). Homo habilis and all the australopithecines are found only in Africa, but erectus was wide-ranging, and is found through Africa and Asia (and was probably in Europe, but no unambiguous skeletal remains are known from there). There is evidence that erectus probably used fire, and their stone tools are more sophisticated than those of habilis.
NARIOKOTOME BOY - photo Discovered by Kamoya Kimeu in 1984 at Nariokotome near Lake Turkana in Kenya (Brown et al.1985; Leakey and Lewin, 1992; Walker and Leakey, 1993). This is an almost complete skeleton of an 11 or 12 year old boy, the only major omissions being the hands and feet. (Some scientists believe erectus matured faster than modern humans, and that he was really about 9 years old (Leakey and Lewin, 1992).) It is the most complete known specimen of erectus, and also one of the oldest, at 1.6 million years. The brain size was 880 cc, and it is estimated that it would have been 910 cc at adulthood. The boy was 160 cm (5'3") tall, and would have been about 185 cm (6'1") as an adult. This is surprisingly tall, indicating that many erectus may have been as large as modern humans. Except for the skull, the skeleton is very similar to that of modern boys, although there are a number of small differences.
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