Describe, illustrate, and explain what scientists have discovered and/or inferre
ID: 85100 • Letter: D
Question
Describe, illustrate, and explain what scientists have discovered and/or inferred regarding the distinctive biological, ecological, and cultural adaptations of African Homo erectus (the species that included Turkana Boy skeleton). Include what is known of the the brain size (cranial capacity), body size, stature, limb proportions, relative size, proportions and orientation of the limb, hand and foot elements, and their relationship to the locomotor patterns of Homo erectus. Also masticatory system of Homo erectus with the masticatory system found in Australopithecus afarensis. Compare the relative size and orientation of jaw elements (ascending ramus, corpus, and symphysis, as well as the size and orientation of the jaw muscles. For the dentition, compare the size and orientation of the incisors, the relative size and homing pattern of canines, relative size and proportions of cheek teeth, thickness of molar enamel. Next, discuss the archaeological evidence for the technology employed by African Homo erectus (Acheulian Industry. Finally, summarize what scientists have discovered or inferred from anatomical, paleontological, and stable isotope studies regarding the probable adaptive patterns (habitat, paleodiet, size, daily and patterns) of Homo erectus in East Africa around 1.5 Mya. Be sure to discuss the importance of cooperation (during food gathering (foraging), hunting, food sharing, food processing, etc.) gatherer societies.Explanation / Answer
Origin
Homo erectus
1.meaning "upright man", from the Latin "to put up, set upright"The first hypothesis of origin is that Homo erectus rose from the Australopithecina in east Africa during—or perhaps even before—the Early pleisticene geological epoch, which itself dates to 2.58 million years ago. From there it migrated, in part, by 2.0 mya, probably as a result of broad desertifying conditions developing then in eastern and northern Africa; it joined the migrations through the Saharan Pump and dispersed around much of theOld world. The fossil record shows that its development from about 1.8 mya to one mya was widely distributed: in Africa Lake turkana,olduvai Gorge ,Georgia,Indonesia sangiran, central java, Vietnam, China and India.
2.The second hypothesis is that H. erectus evolved in Eurasia and then migrated to Africa. They occupied the Dmanisi site from 1.85 million to 1.77 million years ago, which was about the same time or slightly before their earliest evidence in Africa.
Australopithecus afarensis (Latin: "Southern ape from Afar") is an extinct hominin that lived between 3.9 and 2.9 million years ago. A. afarensis was slender built, like the younger A Australopithecus afarensis is thought to be more closely related to the genus homo (which includes the modern human species homo sapiens), whether as a direct ancestor or a close relative of an unknown ancestor, than any other known primate from the same time. Some researchers include A. afarensis in the genus praeanthroupus
The most famous fossil is the partial skeleton named Lucy (3.2 million years old) found by Donald Johansson and colleagues.
Discovery of fossils
1.Haeckel&Research Team:-to find a human ancestor. In 1891, his team discovered a human fossil on the island of Java,DutchEast Indies. Excavated from the bank of the solo River at Trinil in East java, he named the species Pithecanthropus erectus from the Greek "ape", Man"based on a skullcap (calotte) and a femur like that of Homo sapiens.
2.Dubois' 1891 find was the first fossil of a Homo-species (or any hominin species) found as result of a directed expedition and search and which was inspired by Darwin's radical theory that humans, like all other species, evolved from ancestral species,
3.The Java fossil from Indonesia aroused much public interest. It was dubbed by the popular press asJAVA MAN but few scientists accepted Dubois' argument that his fossil was the Transitional Form the so-called “missing Link”between apes and humans.Java Man is now classified as Homo erectus.
Australopithecus afarensis :studies suggest an upright spine and a primarily vertical body plan in primates dates back to Morotopithecus bishopi in the Early miocene of 21.6 Mya, the earliest human-like primates. Known from fossil remains found in Africa, australopithecines represent the group from which the ancestors of modern humans emerged. As generally used, the term "australopithecine" covers all early hominin fossils dated from about 7 million to 2.5 million years ago and some others dated later, i.e., from 2.5 million to 1.4 million years ago. Australopithecines became extinct after that time.
Use of Tool And Fire
At Chesowanja, archaeologists found fire-hardened clay fragments, dated to 1.42 mya. Analysis showed that, in order to harden it, the clay must have been heated to about 400 °C (752 °F). At Koobi Fora, two sites show evidence of control of fire by Homo erectus at about 1.5 mya, with reddening of sediment associated with heating the material to 200–400 °C (392–752 °F). At a "hearth like depression" at a site in Olorgesailie, Kenya, some microscopic Charcoal was found but that could have resulted from natural brush fires.
Australopithecus afarensis :No Evidence Found of using Fire Yet.
Cooking :
Homo erectus cooked their food According to archaeological evidence.
Australopithecus afarensis :No Evidence Found of using Cooking Yet.
Sociality:
Homo erectus was probably the first hominin to live in a hunter gatherer society, and anthropologists believe that erectus was socially more like modern humans than the more Australopithecus like species before it. Likewise, increased cranial capacity generally coincides with the more sophisticated tools occasionally found with fossils.
The discovery of Turkana Boy (H. ergaster) in 1984 evidenced that, despite its Homo sapiens-like anatomy, ergaster may not have been capable of producing sounds comparable to modern human speech. It likely communicated in a proto language lacking the fully developed structure of modern human language but more developed than the non-verbal communication used by chimpanzees This inference is challenged by the find in Dmanisi, Georgia, of an H. ergaster / erectus vertebrate (at least 150,000 years earlier than the Turkana Boy) that reflects vocal capabilities within the range of H. sapiens. Both brain size and the presence of the Broca’s Area also support the use of articulate language.
H. erectus was probably the first hominin to live in small, familiar band societies similar to modern hunter-gatherer band-societies; and is thought to be the first hominin species to hunt in coordinated groups, to use complex tools, and to care for infirm or weak companions.
Australopithecus afarensis on the basis of observations on the relationship between sexual dimorphism and social group structure from modern great apes are applied to A. afarensis, then these creatures most likely lived in small family groups containing a single dominant male and a number of breeding females Other studies have shown there could have been substantial overlap between males and females in size. This, along with the reduction of the canine teeth, has been argued to suggest A. afarensis males and females were monogamous. Males may have engaged in provisioning behavior, and the need for carrying may have led to the evolution of bipedalism.
Anatomy
A) Homo erectus fossils show a Cranial capacity greater than that of Homo habilis (although the Dmanisi specimens have distinctively small crania): the earliest fossils show a cranial capacity of 850 cm³, while later Javan specimens measure up to 1100 cm³, overlapping that of H. sapiens.; the Frontal bone is less sloped and the dental arcade smaller than that of the Australopithecines; the face is more orthognatic than either the australopithecines or H. habilis, with large brow-ridges and less prominent zygomata (cheekbones). The early hominins stood about 1.79 m (5 ft 10 in) only 17 percent of modern male humans are taller and were extraordinarily slender, with long arms and legs.
B)Sexual dimorphisam in H. Erectus males are about 25% larger than females is slightly greater than seen in the later H. sapiens, but less than that of the earlier genus Australopithecus. Regarding evolution of human physiology, the discovery of the skeleton of "Turkana boy" (Homo ergaster) near lake turkana, kenya one of the most complete hominin skeletons ever discovered.
a)Australopithecus afarensis Compared to the modern and extinct great apes, A. afarensis has reduced canines and molars, although they are still relatively larger than in modern humans. A. afarensis also has a relatively small brain size (about 380–430 cm3) and a prognathic face (i.e. a face with forward-projecting jaws).
B) A. afarensis was almost exclusively bipedal, while others propose that the creatures were partly arboreal. The anatomy of the hands, feet, and shoulder joints in many ways favor the latter interpretation. In particular, the morphology of the scapula appears to be ape-like and very different from modern humans. The curvature of the finger and toe bones (phalanges) approaches that of modern-day apes, and is suggestive of their ability to efficiently grasp branches and climb. Alternatively, the loss of an abductable great toe and therefore the ability to grasp with the foot (a feature of all other primates) suggests A. afarensis was no longer adapted to climbing.
C) A. afarensis skeleton strongly reflect bipedalism, to the extent some researchers have suggested bipedality evolved long before A. afarensis in overall anatomy, the pelvis is far more human-like than apelike.
The iliac blades are short and wide, the sacrum is wide and positioned directly behind the hip joint, and evidence of a strong attachment for the knee is clear. While the pelvis is not wholly human-like (being markedly wide, or flared, with laterally oriented iliac blades), these features point to a structure that can be considered radically remodeled to accommodate a significant degree of bipedalism in the animals' locomotor repertoire.