Homo erctus:africa(paranthropus): originally described as Pithecanthropus erectus, the java ape man,ranged across africa into eurasia from over 1.6 to .12mya.this hominid made stone tools and knew use of fire and was probably the direct ancestor of haomo sapiens who replaced it.it is supposed to have evolved side by side paranthropus upto 1 mya and beacme extinct by 0.12 mya in the wake ofcompetition from more efficient human forms. Rest of paranthropus is discussed in earlier section.
Europe(Homo erectus Heidelbergenensis):
Mauer,germany.lower jaw with all its teeth..lower pleistocene.
The jaw is very large and masisve and it gives avery powerful appearance.the height and breadth beingabout 6.6 cmand 5 cm.the horizontal ramus is very high and massive.,much more so than modern man.the lower border of it is concave as in baboons whereas in anthropoid apes and men it is not so.the obligue ridge on the inferior surface is faint,suggesting weak mylohoid mussles.
The angle of jaw is truncated as in the orang andd neanerthal man.
The alveolar borgder i sparabolic in shape.in the apes it is u shaped.no diastema is present.the teeth are of quite ordinary size.the incisors are normal.the canine is small and it does not project beyong the level of other teeth.
Thus it is seen that the jaw shows some remarkable simian feature while the dentition is althogether human.
Pithecanthropus erectus:(ape man with erect posture)(java man)
trinil,Java.The skeletal material consist of a skull cap, three teeth,a lower premolar,two upper molars and a femur.middle pleistocene.the skull cap is18.5 cm in length and 13 cmin breadth thus giving a cephalic index of 70.
the cranial capacity is estimatedto be940 cc.inrespect it stands between ape(650) andman(1700).the cranium is flattened in vertical direction.in respect of the development of brain also it is intermidiate between man and ape.
The teeth are of enormous size.each one is larger than the corresponding human tooth.the roots of the molar are strong and divergent(ape like).the crown resemble more that of man than that of apes.
Femur is complete and 45.5 cmin length, which suggest height of the individual to be 167 to 170 cm.the linea aspera is fully developed, a suggestion of erect posture.
Pithecanthropus stands in the direct line of evolution of modern man, being truly intermidiate between man and the apes.
Pithecanthropus stands on aside branch that rises from the main human stem.the side branch could not grow more and thus it became extinct.
Pithecanthropus is no more than a highly evolved giant ape related to the gibbon group.
Though pithecanthropus shows a mixture of antropoid ape and humanoid characters,its erect posture, its brain formation,its other characteristics are more human than simian.chin is absent diastema is present.
Sinanthropus pekinensis:(Peking man)
Peking,china.two fossil teeth.Later skull fragments of about 40 different individual of both sexes was found.middle pleistocene.avg. Max. Length of the skull is 19.4 cm.the cranial index is72.2.thus it is a very long head.the cranial capacity varies from 850 to 1300cc.theskull bones are verythick and massive.
The forehead id receding.it is separated bya distinct furrow fromthe superorbital ridge which are pronounced and continuous.
The orbits are large.the molar bones are very high and prominent.the nasal bridge is relatively high and broad.the nose as a whole is very broad.the nassl spine is absent.the upper jaw is not hallowed out as in modern man.chin is absent. Diastema is absent
List of differences between java man and peking man will be updated here:
Impelling causes of h.erectus evolution:
Majority put the time of origin of h.erectus at the beginning of pleistocene,some 2 mya.for about 1 million year homo existed side by side with paranthropus.australopithecine radiated to give rise to homo erectus on the groundsof feeding habits-australopithecines remained specialised small object feeder,while homo gradually adapted for an omnivorous diet with emphasis on hunting and meat eating.naturally the two groups are differentiated mainly on the basis of dentition jaw and skull.
It is hyptonized that first glaciation resulted in large scale destruction of forests leaving only a few pockets with nuts and seeds.australopithecines remained confined to these vestiges of forests.but homo with slightly larger brains and enhanced mental capabilities adopted omnivorous habits.
Characters of homo erectus.
1). cranial capacity 775 to 1421cc. Highestin narmada man form india.
2).Height of cranium is more than width like us.
3).More anterior placement of foramen magnum indicating an erect posture.
4).dental arcade more parabolic than australopithecus, nearing that of h.sapiens.
5).Dental morphology similar to modern man, all being of same size and shape.
6).Taurodontism(extension of pulp cavity)present.
7).Linea aspera were developed in fumer.
8).Zygomatic arch thin like homo sapiens.
9).Sagittal crest reduced or absent as in homo sapiens.
10).Parietal lobe of brain well developed signifying development of languages as means of communication and thinking process.
11).sexual diamorphism was not much pronounced.
1).Sloping forehead.it is vertical in us.
2)prominent brow ridge extending as a bar of bone across nasal root and both orbits.it is slight or nearly absent in us.
3).Angular occipital region .it is rounded inus.
4).Widest part of craanium at the level of ears.it is at higher level in us.
5)Flatter nassal area.it is somewhat elevated in us.
6)bones of cranium thick,the thickness being in the range of 7-10mm. It is 5.2mm thick in us.
7)mandible larger that makes the face prognathous.it is smaller in us.
8)no chin,though there is thickening of mandible in side called mandibular torus.
9)teeth larger molars with divergent roots,not in us.
Tool culture is present.
Evidences of use of fire for the first time.
Hunting as indicated by use of tools.
Cannibalism-some fracture skull seems or suggests it to be technically removed shows cannibalism.
Language and communication-it is supposed that tool making and its use,hunting and group living acted as selective forces and those with developed memory sites in occipital lobe,thinking sites in frontal lobe and different motor-areas in cerebral cortex were favoured by the natural selection.this reselted ingradual development of brain.
Sexual behaviour:although females approach males in body-size,there is marked differene in the facial features of males and females.
Origins of homo erectus:
homo habillis existed around 2 mya, just before advent of h.erectus.its cranial capacity was 750cc,matching with the cranial capacity of east african and java homo erectus which are supposed to be more primitive homo erectus. its certain cranial features was more advanced than australopithecus,approaching h.erectus.these characters included more rounded skull with lesser crests,less massive mandible with dental arcade.