If asked when humans evolved on this planet, many or all of us, at a sudden, would answer “millions of years back”, which is the easiest guess of time period when one is literally blank about the exact period. So, now, lets try to trace back the evolutionary time and stages of the most civilized species of the Animal kingdom: The Homo sapiens. The first Hominids(members of our family) have been around 0.1 percent of history of our planet.
• Ramapithecus: Some scientists accept it as the first true Hominid from miocene epoch. The fossils of Ramapithecus (primarily tooth and jaw) were found in Siwalik hills of India, Kenya and various other places including Turkey, Hungary and Greece. They date back between the period 14-9 mya(million years ago).
Their characteristics included-
°Reduced and vertically implanted incisors and canines.
°Flattened and thick enameled premolars and molars, which were probably adapted for heavy chewing and processing heavy stuffs.
°Little or no diastema.
Ramapithecus strongly suggests the exploration of new dietary sources, which indicates a shift from softer forest fruits and vegetables relied upon by the apes. This may be directly related to climatic changes in the later part of miocene that led to increase in open grasslands and decrease in forest habitat of apes. There is a greater possibility that this homonid was apparently moving into a new ecological niche.
• Australopithecines: They emerged on rolling savannas of eastern and southern Africa some 5.6 million years ago. They are atleast partially erect, bipedal with reduced snout and expanded braincases. They can be classified into two major contemporaneous groups, the robust and gracile form, which suggests two separate and distinct form of evolution. Australopithecines are divide into two genera:-
* Austalopithecus: It includes slender forms like-
It was in the year 1925 that Dart discovered the first fossils from Taung in South Africa. This genus includes the gracile form and represented by species mentioned above. They were 4 feet tall, weighed no more than 50-100 lbs.
Other characteristics include-
°A well developed forehead suggesting the expansion of frontal lobes of brain.
°An elevated cranial vault indicating a major portion of brain lies above the level of face unlike the pongids or apes where it is behind or below the face level.
°Cranial capacity between 450-600 cc.
°Skull probably well balanced and foramen magnum placed slightly forward, indicating erect posture.
°Hominid post cranial skeleton and illium of pelvis is broad and short indicating a bipedal locomotion, probably a better runner than a walker.
Morphological characters of genus Australopithecus suggest them to be ancestors of modern man.
* Paranthropus: It includes the robust forms-
The fossils were discovered from Tanzania, Kenya and Ethiopia. Height of adults was close to 5 feet, weighing as much as 100-150 lbs. They were adapted to savanna grassland environment. Their teeth were fully Hominid, arranged in parabolic arch, slightly more U-shaped with relatively small incisors and canines. Skull was larger than Australopithecus, having cranial capacity around 450-600 cc. This animal has lower brain to body size ratio.
Other characteristics include-
°Cranial vault not well rounded and expanded.
°Mixture of Gorilloid and Hominid traits.
°Moderately developed sagittal crest, massive jaws with moderate prognathism and entire dentition was probably designed for extreme crushing and grinding.
°Large supra orbital ridges without conspicious forehead.
• Homo habilis: It was discovered in the early 1960s at Olduvai Gorge by Louis Leakey. The age of the fossil is estimated to be 2-1.5 mya. It appeared close to modern human beings. Its features were more refined with somewhat more modern teeth. They concluded that they found the first real human being and named it H. habilis. In 1994, Bernard Wood emphasized that the foramen magnum is further forwardly placed in Homo habilis. The teeth are narrower but not as small as that of Homo erectus.
°The cranial capacity ranges between 650-800 cc.
°The brain size shows evolutionary advancement.
°Frontal lobes of brain are well developed.
°The cranial vault is rounded.
°The hind limb morphology clearly approaches the human foot.
°Hominid dental structure, the premolars particularly, are human like.
°Larger brain shows larger gestation period, larger newborns and greater longevity. Brain enlargement was perhaps the cause and effect of dietary shifts.
Homo habilis was a tool maker. The tool kit is referred to as “Oldowan Industry”.
• Homo erectus: They represent the second stage in hominid evolution. They date back to 1.6-0.12 mya. Their average cranial capacity is 1000 cc, which is larger than australopithecines. Eugene Dubois first discovered the specimen of Homo erectus from Java in 1891, hence, this fossil is commonly known as Java Man.
Their general characteristics are-
°Height 5 ft. average.
°Compared with early Homo, H. erectus had small teeth.
°H. erectus was the first hominid to have third molar as in modern humans.
°Face was less prognathic.
°At this stage of time, some kind of vocal communication seems possible.
°They lived in caves and used animal skin as clothing.
The oldest recognised tool, the chopping tool was their evolutionary achievement. It is belived that the beginning of rituals, formation of nuclear families and some other aspects of human socio-cultural system was developed by H. erectus. This hominid knew the use of fire and was probably the direct ancestor of Homo sapiens. Homo erectus were the first officially named pre-historic species of human genus Homo.
• Neanderthal Man: The first specimen were discovered in a cave in the Neander Valley near Dusseldorf, Germany in 1856. It aged between 170000 years ago to 35000-40000 years ago. Neanderthals can be distinguished into two types on the basis of their morphological features:-
* Conservative type: Also called Classical Neanderthals, they appeared 70-80 thousand years ago and became extinct about 35000 years ago.
La – Chapelle – Aux – Saints: Found in August, 1908, in France.
* Progressive type: They were discovered during 1931-1932 in Jerusalem.
Neanderthals had developed speech centres and thus, were capable of communicating. Primitive sort of social life associated with division of labour, religion and culture can be seen. Evidences of ceremonial burial of their dead bodies have been found.
• Rhodesian Man: T. Zwigelaar in 1921 found an almost complete cranium in Northern Rhodesia, Africa and more skeletal remains were found by A.S. Armstrong in 1921 and by H. Hrdlicka in 1925. Their body weighed around 280 lbs and height was upto 5 ft. 10 inches. On the basis of faunal and archaeological evidences as well as chemical analysis, it was inferred that Rhodesian man lived during early Pleistocene or late Pliocene.
°The cranial capacity is between 1280 – 1400 cc.
°The skull is dolicocranial.
°The foramen magnum occupies central position, indicating perfect equilibrium of the skull on the vertebral column.
°The teeth exhibit modern human proportions.
°Femur is straight, not bowed like as in Neanderthals and they were an upright bipedal walker.
• Cro-Magnon Man: In 1868, Louis Larter excavated the rock shelter of Cro Magnon on the banks of Vezere. The cranial capacity of this species was around 1600 cc. Their height was around 5 ft. 6 inches.
°Their face is relatively flat and very broad.
°The cheek bones are large and protruding
°Nose is narrow, long and high, i.e. Leptorrhine.
°Skull is narrow and long.
This combination of a short broad face with long narrow head is known Cranial disharmony.
• Grimaldi Man: The discovery was made in a cave named Grotte des Enfants near Mentone in Italy during June 1901. Their cranial capacity was found to be around 1454 cc.
Their forehead is straight, well developed and slightly bulging. Grimaldi skeleton exhibit Negroid features in the proportion of limbs. Their nose is Platyrrhine and chin is not greatly developed.
• Chancelade Man: It was discovered in 1888 from a rock shelter at Chancelade in Central France Region. Their cranial capacity was around 1530 cc.
°Forehead is bulging and rising vertically.
°Cheek bones are prominent and strongly developed which gives a flat appearance to the face.
°Dolico cranial skull.
The course of cultural evolution since Cro-Magnon has been divided into Palaeolithic(age of tools of stone and bone), Mesolitic(age of animal husbandry) and Neolithic(age of agriculture, knowledge and use of clothes and utensils).
As evolution is a dynamic process, humans will continue to adapt to the environment and evolve throughout the ages ahead. In the natural course of evolution, according to Dr. Sapiro, the present human is likely to change into a human of future- Homo sapiens futuris, with taller and hairless body, tomb like head and larger brain and with no fifth toe.
Its our new future! Stay fit, stay adaptive!!
Article by:- Avanish Tripathi
© Alysane Society
© Avanish Tripathi