Evolution of Man: Morphological Changes involved in Evolution of Man!
Place of origin of man:
The fossil evidence clearly indicates that origin of man occurred in Central Asia, China, Java and India (Shivalik Hills). It has been established that Dryopithecus is one of the oldest fossil which in turn evolved into apes and men.
For the sake of convenience, the origin and evolution of man can be studied in the following three major headings: prior to ape men, ape men including prehistoric man and true men including the living modern man.
Morphological Changes involved in Evolution of Man:
The following main morphological changes occurred in the ancestors of modern man:
(1) Narrowing and elevation of nose.
(2) Formation of chin.
(3) Reduction of brow ridges.
(4) Flattening If face.
(5) Reduction in body hairs.
(6) Development of curves in the vertebral column for erect posture.
(7) Formation of bowl like pelvic girdle with broad ilia (pi. of ilium) in support of viscera.
(8) Increase in height.
(9) Attainment of erect posture and bipedal locomotion.
(10) Enlargement and rounding of cranium.
(11) Increase in brain size and intelligence.
(12) Broadening of forehead and with vertical elevation.
Prior to Ape men:
1. Dryopithecus Discovery:
The fossil of Dryopithecus africanus was discovered from Miocene rocks of Africa and Europe. It lived about 20-25 million years ago.
It was more ape-like but had arms and legs of the same length. Heels in its feet indicate its semierect posture. It had large brain, a large muzzle and large canines. It was without browridges. It was arboreal, knuckle-walker and ate soft fruits and leaves. Dryopithecus africanus is regarded a comman ancestor of man and apes (gibbons, orangutan, chimpanzee and gorilla).
2. Ramapithecus Discovery:
It has been established that in late Miocene epoch Dryopithecus gave rise to Ramapithecus (‘Rama’= The hero of Indian legend, pithecus = ape) which was on the direct line of human evolution, Ramapithecus survived from late Miocene to Pliocene. Thus he appeared about 14-15 million years ago. Fossil of Ramapithecus was discovered by Edward Lewis (1932) from Pliocene rocks of Shivalik Hills of India.
Perhaps it walked erect on its hind feet. It was more man-like and lived on the tree tops but also walked on the ground. Its jaws and teeth were like those of humans. Its small canines and large molars suggest that Ramapithecus ate hard nuts and seeds like modem man. Perhaps it could walk erect on its hind feet. It became extinct about 7-8 million years back.
Kenyapithecus wickeri was discovered by L.S.B. Leakey (1962) from Pliocene rocks of Kenya (Africa). It was similar to Ramapithecus. But Ramapithecus was older than Kenyapithecus.
There is a gap of about 9 to 10 million years in Ramapithecus and Australopithecus (to be described).
Ape Men including Prehistoric Men:
1. Australopithecus (First ape man):
The early human stock gave rise to Australopithecus.
Raymond Dart (1924), South African anthropologist, discovered the fossil of Australopithecus africanus (African Ape man) from Pliocene rocks near Tuang in Africa. He appeared about 5 million years ago. Actually skull discovered by Dart was of 5-6 year old baby so it is also called ‘Tuang baby’. Some fossils of A. africanus were also discovered from Pleistocene epoch.
Australopithecus africanus was about 1.5 metres high and had human as well as ape characters. It was with bipedal locomotion, omnivorous diet and had erect posture. It had human like teeth but it had more of an ape brain than a human brain. Its brain capacity was about 500 c.c. similar to that of an ape.
He lived in caves. Brow ridges projected over the eyes. It did not have chin. There was lumbar curve in the vertebral column. The pelvis was broad. Australopithecus africanus existed until about 1.5 million years ago and gave rise to Homo habilis about two million years ago.
Australopithecus africanus also gave rise to man-like apes called Australopithecus robustus and Australopithecus boisei along a separate line that ended blindly (They did not give rise to any other creatures).
In 1981 Donald Johanson, found a 3.2 million years old skeleton of a female human ancestor. He nicknamed it Lucy. Lucy’s scientific name is Australopithecus afarensis. Six species of Australopithecus are known. These are A. africanus (African Ape man, Southern Ape or Tuang baby), A. afarensis (Lucy), A ramidus, A aethiopicus, A. robustus and A. boisei.
2. Homo habilis (Able or Skillful man, the tool maker, or ‘Handy man’) Discovery:
L.S.B. Leakey and his wife Mary Leakey (1960) discovered the fossils of Homo habilis from Pleistocene rocks of olduvai Gorge in East Africa. He lived in Africa about 2 million years ago.
Characteristics. It was about 1.2 to 1.5 metres tall. It had bipedal locomotion, moved erect and wap omnivorous. It had about 700 c.c. cranial capacity. The teeth were like that of modern man. Homo habilis (habilis – mentally able or skillful) was the first tool maker and used tools of chipped stones extensively.
It is also called handy man because heaps of tools found with these fossils included sharpened stones which indicate that Homo habilis was capable of ‘making tools’. He also led community life in caves and greatly cared for the young ones.
3. Homo erectus (Erect man):
Homo erectus appeared about 1.7 million years ago in middle pleistocene. H. erectus evolved from Homo habilis. He was about 1.5-1.8 metres tall. Homo erectus males were probably larger than females. He had erect posture. His skull was flatter than that of modem man.
He had protruding jaws, projecting brow ridges and small canines and large molar teeth. The cranial capacity was 800 to 1300 cc. Cranium was domed to accomodate the large brain. He was omnivorous. He made more elaborate tools of stones and bones, hunted big game and perhaps knew use of fire. Homo erectus includes three fossils: Java Ape-man, Peking man and Heidelberg man.
(i) Java Ape man. Discovery:
In 1891, Eugene Dubois discovered a fossil from pleistocene rocks in central Java (Island of Indonesia). Eugene Dubois named it as Pithecanthropus erectus. Pithecanthropus means ‘ape man’. Mayer in 1950 assigned it as Homo erectus.
Body 1.65 to 1.75 metres tall and weight about 70 kg. Legs long and erect, but body slightly bent when moving. Inconspicuous chin and somewhat broader nose. Forehead low and receding, but brow ridges high like those of apes. Skull cap thick and heavy, flattened in front. Cranial capacity 800 to 1000 cc. (average 950 cc).
Lower jaw large and heavy. Teeth large, but quite like those of modem man, except larger canines of the lower jaw. Lips thick and protruding. He was omnivorous and cannibal. Perhaps he was the first prehistoric man to make use of fire for hunting, defence and cooking.
(ii) Peking Man. Discovery:
W.C. Pei (1924) discovered the fossils of Peking man from the lime stone caves of Choukoutien near Peking (Beijing- capital of China was formerly known as Peking) and named them Sinanthropus. Davidson Black (1927) named it Sinanthropus pekinensis. Mayer (1950) renamed it as Homo erectus pekinensis (a subspecies). The pleistocene rocks from which fossils of Peking man were excavated are about 6 lakh years old.
Placing Java ape man and Peking man as subspecies of Homo erectus has a sound basis, because of close similarities between these. The body structure was quite similar in both. Being about 1.55 to 1.60 metres tall, Peking man was slightly shorter and a little lighter and weaker.
The only noticeable difference of Peking man from Java ape man was its large cranial capacity which ranged from 850 to 1100 c.c. Like Jave ape man, the Peking man was omnivorous and cannibal. There is a clear evidence of use of fire by it. It has been confirmed that both Java and Peking men used to live in caves in small groups or tribes. The tools of Peking man were relatively more sophisticated.
(iii) Heidelberg man. Discovery:
In 1908 one of the most perfect fossil jaws belonging to middle Pleistocene was found by workmen working near Heidelberg, Germany. It was shown to Otto Schoetensack, who gets the credit for its discovery. It was named Homo erectus heidelbergensis.
It had lower jaw with all the teeth. The teeth were human like. The massive jaw was ape-like. He used the tools and fire. The cranial capacity is believed to be about 1300 cc; which is intermediate between those of erect man (H. erectus) and Neanderthal man (H. sapiens neanderthalensis). Thus it is regarded as intermediate between pithecan- thropines and Neanderthalers.
There is another gap of about 50,000 years in the fossil record of evolution of man.
True men including the Living Modern Man:
1. Neanderthal Man (Homo sapiens neanderthalensis). Discovery:
Fosssils of Neanderthal man were first obtained from Neander Valley in Germany from the late Pleistocene epoch by C. Fuhlrott (1856). Later many other fossils were excavated in various countries by different palaeontologists.
He had slightly prognathous face (having a forward projecting face and jaws). Neanderthals walked upright, as we do, and had low brows, receding jaws, and high domed heads. If there was anything truly different about them, it was that they were much stockier than we are. Their cranial capacity was 1,300 to 1,600 cubic centimetres.
Neanderthals existed half a million years ago but were most numerous from about 100,000 years ago. They became extinct 30,000 years ago.
Neanderthals were the legendary cave dwellers. They have been portrayed as having heavy brow ridges and humped backs.
Neanderthals were adapted to a cold environment. They encountered the succession of glaciers that passed over most of the northern temperate regions of the world. They were not only skilled hunters but true predators, a specialization that did not occur among hominids before or after them. The neanderthals were cannibals.
They fashioned the skin into clothing to protect themselves against the harsh climate. Natural caves became campsites that were illuminated and heated by fire. It is believed that he buried his deed with flowers and tools. He may had a religion.
It is usually considered that Homo sapiens neanderthalensis did not evolve into Homo sapiens.
2. Cro-Magnon man (Homo sapiens fossilis). Discovery:
It has been known as Cro- Magnon man, because its fossils were first discovered in 1868 from Cro-Magnon rocks of France by MacGregor. Cro-Magnon man emerged about 34000 years ago in Holocene epoch. Thus, it is regarded as most recent ancestor of today’s man.
The Cro-Magnon man had, like us, about 1.8 metres tall, well-built body. Its face was perfectly orthognathous (Jaws do not project forward) with an arrow, elevated nose, broad and arched forehead, moderate brow ridges, strong jaws with man-like dentition, and a well developed chin. Its cranial capacity was, however, somewhat more than ours, being about 1650 cc.
It is, therefore, believed that Cro Magnon man was somewhat more intelligent and cultured than the man of today. It could walk and run faster and lived in families in caves. It made excellent tools and even ornaments, not only of stones and bones, but also of elephant tusks. Its tools included spears, bows and arrows, as he was omnivorous. Use of the skin clothes by this man is also confirmed. A number of cave paintings done by Cro-Magnon man have been discovered. It became extinct about 10,000- 11, 000 years ago.
The Cro-Magnon man was the direct ancestor of the living modem man.
3. The Living Modern Man (Homo sapiens sapiens) Discovery:
Further evolution of man after Cro-Magnon involves the evolution of culture rather than that of anatomy. Homo sapiens sapiens appeared about 25000 years ago in Holocene epoch and started spreading all over the world about 10,000 years ago.
Morphologically, the transition is marked merely by a slight raising of skull cap, thinning of skull bones, a slight reduction in cranial capacity (1300-1600 c.c. average about 1450 c.c.), and formation of four curves in the vertebral column.
It is believed that the man of today first appeared about 11,000 or 10,000 years ago in the region around Caspean and Mediterranean Seas. From there, its members migrated westwards, eastwards and southwards, respectively changing into the present day white or Caucasoid, Mongoloid and black or Negroid races.
Cultural Evolution of man:
The course of cultural evolution has been divided into palaeolithic (age of tools of stones and bones), mesolithic (age of animal husbandry, language, reading and writing), neolithic (age of agriculture, knowledge and use of clothes and utensils), bronze age and the present iron age.
Cranial Capacities of Apes and Man:
(in cubic centimetres)
(in cubic centimetres)
|1. Chimpanzee and Gorilla||325-510 c.c.||6. Heidelberg man||1300 c.c.|
|2. Australopithecus||500 c.c.||7. Neanderthal Man||1300-1600 c.c.|
|3. Homo habilis||700 c.c||8. Cro-Magnon Man||1650 c.c|
|4. Java Ape Man||800-1000 c.c.||9. Living Modern Man||average about 1450 cc.|
|5. Peking Man||850-1100 c.c.|