Australopithecus
A Australopithecus is a Hominidé disappeared having lived between approximately 4,4 million and 1 million years before our era. The kind Australopithecus (of the Latin australis , “of the south”, and the old Greek πίθηκος , píthēkos , “monkey”) was defined by Raymond Dart at the time of discovered Australopithecus africanus in 1924. The Australopithecus present at the same time antiquated characters (not very bulky brain) and advanced characters (teeth close to that of the kind Homo ). Their locomotion is generally mixed and associates a form of bipédie with a capacity with climbing still marked. The human line is probably resulting from the old shape gracile of Australopithecus.
Evolution and genetics
The successive discoveries of Fossil bones S in several areas of Africa, the progress made in the reading of the chromosomal formulas and the biology of the development, which connects the genetic program to the formal amendments of the species during their evolution, allow a better comprehension of the evolution of the higher monkeys and the man.
The Orang-outang, the Gorilla, the Chimpanzee and the Homme have five identical chromosomes inherited their common ancestor, the proconsul. Approximately 12 million years ago, the orang-outang evolves/moves independently in Asia; the existence of an ancestor common to the three other lines is proven by the indisputable presence of 11 common chromosomes and 7 transferred chromosomes. 5 million years ago, the chimpanzee, the gorilla and the Australopithecus (i.e. the préhumain) isolates himself definitively to give rise to the current species.
Great discoveries
Until today, the discoveries of fossils of Australopithecus had exclusively as a framework Africa. Among the most significant places where were raised of the traces of bearing settlement on several hundreds of thousands of years, one will note the Ethiopian high plateau, the area of the big lakes and the high plateaus of the south of the continent.
The most vestiges come from Tanzania: sites of Olduvai, Laetoli, explored by Louis Leakey; of Ethiopia: valley of Omo, basin of Awash; and of the Kenya: Kanapoï, Lothagam, neighborhood of the Lake Turkana (Koobi Drilled, Ileret, Allia Bay), explored by Richard Leakey, like by kenyo-American teams. The area of the Ethiopian Afar was the framework, since 1974, of some of most important discovered of which the relatively complete skeleton of a female individual of Australopithecus afarensis , to which one gave the nickname of Lucy. In 1979, one put at the day in the locality of Hadar a layer containing of the pieces of cranium, the teeth, of the mandibles, as well as bones of the basin and long bones Australopithecus going back to 3,6 million years to 4 million years. Not far from there, in the basin of the Awash means, the French and American teams found remainders of Australopithecus quite as old and more recent bones (of 1,8 million years to 2,6 million years) of Homo habilis .
Main features
The considerable number of osseous remains one has today made it possible to reconstitute, in spite of the diversity of the elements, several almost complete individuals; moreover, the presence of remainders of fauna and traces of installation on the grounds quoted previously authorized the first reconstitution of the lifestyle of our “distant cousins”. A point on which all the researchers are from now on unanimous is that of the statute of these Hominides: narrowly related (biologically) with the kind Homo , they were different from it by giving rise to a collateral branch; their evolution is sensitive until approximately 1,5 million years, through various species which, while preserving a general architecture of cranium rather primitive (and, under certain aspects, still simienne), evolved/moved by acquiring a body morphology in all points similar to that of the contemporary species dThe Australopithecus had the station Bipède, but does not have a frank bipédie, its bipédie is partial (still moves by brachiation per moment), went like the modern man and were capable to run on their two feet (as opposed to what one could think in the past). That was confirmed by the sensational discovered one (in 1978 by Mary Leakey), close to Laetoli (Plaine of Serengeti, in Tanzania), of a double series of prints of step preserved since 3,6 to 3,8 million years.
The structure of the hands of the Australopithecus is identical to that of human, apart from the articulation of the first phalange of the inch, which does not allow all the movements of a hand of modern man (but who is nearly identical to that d
However, this limit with it only is not sufficient to explain the diversity of behaviors between the two kinds; there existed admittedly of other morphological differences with the first Homo known, divergences whose functional significance is still today an object of studies. Above all, the cranial capacity of the Australopithecus is slightly lower (550 cm, whereas that d
Phylogenetic position
According to certain researchers, Australopithecus afarensis could be the common ancestor of the Australopithecus and kind Homo ; this assumption is disputed by others, which estimate that separation between the two kinds could have taken place at one quite former time.
Place in the evolution of the human Line
The fossil remainders seem to indicate qu'Australopithecus is the common ancestor of the group distinct Hominides called today Paranthropus (“australopithécinés robust”) and extremely probably from the kind Homo which includes/understands the modern men. Although the intelligence of these homininés early undoubtedly did not exceed that of the modern anthropoïdes, the biped stature is the key obviousness which distinguishes this group from the primates which preceded it and which are quadrupeds. Morphology d'Australopithecus contradicts what the scientists had believed before, namely, that a bulkier and more complex brain preceded the bipédie. Insofar as Australopithecus one were homininé undeniable according to the prints of step which it left in Laetoli, it should be been appropriate that its small brain did not prevent it from being biped. One always discusses to know how the bipédie evolved/moved several million years ago (several theories are always under study). However, the advantage of the bipédie was that it made it possible the hands to be free to catch objects while the eyes could better examine above them large grasses to find sources of food possible or to locate the predatory ones.The radical changes in morphology occurred before australopithécinés the graciles advanced; the structure of the basin and the feet hardly distinguish them from the modern men. The teeth present also same alignment with small canines; however, the evolution towards Paranthropus gave rise to larger and more robust teeth. Australopithécinés were to face a particular challenge while living in savanna. They were the slowest primates to move of their time and much of them became the prey of the carnivores (like the lions and Dinofelis, today extinct).
If the majority of the species of Australopithecus were not able to use the tools than the modern not-human primates, one realized however that the chimpanzees use simple instruments (i.e. they open of nuts with stones and that they introduce of small branches into the termitières); one more recently made the same discovery for the gorillas. However, Australopithecus garhi really seems to have been most advanced of the line with its tools manufactured out of stones which are undoubtedly former to the first representatives known for the moment of the kind Homo , Homo habilis and Homo rudolfensis . The remainders d'Australopithecus gahri were accompanied by tools and remainders of cut out animals, which suggests the beginning of a manufacture of tools. That led many scientists to think qu'Australopithecus garhi can be an ancestor of the Homo kind. However the anthropologists and the researchers await others discovered to determine which was the true species of our ancestors.
References
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