Exploration of the Geological Ages

Scientific Discoveries and The Changing Perceptions of the Human Evolution

• Conception of the solar system has been changing from twentieth

century

• The earth is about 4.5 billion years old and humans appeared on it only some 200,000 years ago

• The many advances in the physical sciences in the 20th century have greatly amplified our understanding of the earth’s history

• Unveiled complex mechanisms of the biological evolution of species is being explored by the developments of the genetic science

• In recent years, advances in DNA(Deoxyribonucleic Acid) analysis have provided important evidence regarding the process of human evolution

Roots of the geological and biological evolutionary theories

• Charles Robert Darwin’s path-breaking book, The Origin of Species (1859) explained :

1. How new species arose due to adaptation ? 2. How the process of natural selection led to the survival of the fittest ?

• Darwin had been deeply influenced by Charles Lyell’s Principles of Geology

(1830–33) • Charles Lyell explained the past changes in the earth’s surface as results of still-

continuing processes such as wind action, erosion, earthquakes, and volcanic eruptions

• Thomas Henry Huxley’s Evidence as to Man's Place in Nature (1863) extended Darwin’s idea of evolution to human beings

• The authoritative writings of such scholars ultimately revolutionized prevailing ideas about how and when human beings appeared on the earth

• Evolutionary theory had enormous and unsettling implications, and it is not surprising that many 19th century Europeans found it difficult to accept

• according to biblical theory of creation which nature and humans were created in all their perfection by a divine agency according to a divine plan

• It was not easy to accept the idea that reptiles and insects had appeared on the earth long before human beings, or to recognize certain similarities between humans and chimpanzees, or to think of the world as millions of years old

• Just as disconcerting was the fact that evolutionary theory suggested that change in nature was continuing, unpredictable, and unstoppable

• The breakthroughs in the natural sciences had an immediate and major impact on prehistoric archaeology

• Stone tools had been found and reported in earlier decades, but a theoretical perspective within which such finds could be understood was absent

• For instance, in 1836, a French customs officer named Jacques Boucher de Perthes had discovered flint tools in the Somme valley

• He had argued that such tools, in some instances found along with bones of extinct animals, were remains of humans who had lived long before the biblical flood

• De Perthes’ work was greeted by general scepticism until his finds were authenticated many years later by the geologists Hugh Falconer and Joseph Prestwich, and the archaeologist John Evans.

• Today, geologists divide the history of the earth into four eras or ages related to the evolution of life forms:

1. Primary (Palaeozoic) 2. Secondary (Mesozoic) 3. Tertiary 4. Quaternary

• The Tertiary and Quaternary together form the Cenozoic or the age

of the mammals, which began about 100 million years ago (mya)

• The Cenozoic is divided into seven epochs, of which the last two—the Pleistocene and Holocene—are especially important for the story of hominid evolution

• The Pleistocene began about 1.6 mya, and the Holocene (or Recent period, in which we live) about 10,000 years ago

• The process of natural selection, which favours traits that help the species in adapting to the environment

• Over time, this process can give rise to a new species

• The terms species (or specie) and genus are central to discussions of evolution

• A species includes organisms that are similar in physical structure and behaviour and which interbreed with each other, or which could do so if they had access to each other

• A genus is an assemblage of related species

• Take the following example: Canis familiaris (the domesticated dog), Canis lupus (wolf), and Canis aureus (jackal) all belong to the same genus—Canis—which is mentioned first

• The second word is the name of the species they represent

• There are many differences in skin colour, facial features, hair colour, body build, height, etc. among modern human beings living in different parts of the world, but we all belong to the same species of anatomically modern humans—Homo sapiens sapiens (the second sapiens refers to our sub-species)

• Homo sapiens is a Latin term, meaning ‘thinking man’

GEOLOGICAL AGES AND CORRESPONDING LIFE FORMS

Palaeo-anthropologists Statements • They have used fossil evidence to piece together the fascinating

story of the biological and cultural evolution of early humans • It is sometimes difficult to identify a species on the basis of

incomplete skeletal material and it is not always clear whether these remains are representative of the entire population of an area

• Nevertheless, different stages in the process of human evolution can be identified, as can the implications of crucial biological markers such as

1. increase in cranial capacity (brain size) 2. changes in pelvic structure 3. the beginnings of bipedalism (walking erect on two legs) 4. the modification of dental structure due to changing food habits • Some important aspects of the cultural evolution of early humans

include 1. the making of stone tools 2. the emergence of some kind of social organization, 3. the beginnings of language 4. the capacity for symbolic thought

• The earliest known hominids (man-like species) were members of the Australopithecus genus

• who lived roughly between 4.4 and 1.8 mya, and their remains have so far only been identified in Africa

• The earliest of these, Ardipithecus (or Australopithecus ramidus) seems to have evolved from some common ancestor of the hominid and pongid ape lines in sub-Saharan Africa about 4.4 mya

• While the Australopithecines may have used naturally available material as tools, there is no conclusive evidence that they were tool makers

• Fossil evidence of the earliest representatives of the genus Homo—

Homo habilis (hand-using man)—was found at sites such as Koobi Fora in Kenya and the Olduvai gorge in Tanzania, and is dated about 2 mya

• The earliest stone tools have been found at Hadar in Ethiopia and have been dated about 2.5 mya

• Homo erectus (named for his/her fully erect posture) appeared in East Africa around 1.7 mya

• From here, this species seems to have spread to various parts of Africa, Asia, and Europe

• The first Homo sapiens appeared a little less than 500,000 years ago

• From about 130,000 years ago, there is evidence of Homo sapiens neanderthalis (Neanderthals) in various parts of western and central Asia and in Europe

• Whether the Neanderthals evolved into Homo sapiens or whether they became extinct remains a mystery

• Apart from Africa and Europe, hominid remains have also been found in various parts of Asia

• Remains of Homo erectus in Java have been dated between 1 to 2 mya and were associated with animal bones of many species but no stone tools

• Remains of Homo erectus discovered in the Zhoukoudian caves 50 km south-west of Beijing are dated between 0.58 to 0.25 mya

• This site also yielded over 20,000 stone tools and bones of 96 mammalian species

Hominid Remains in the Indian Subcontinent

• From the 19th century onwards, several remains of fossil apes were discovered in the Siwalik hills, the outermost range of the Himalayas

• Given rather dramatic names such as Ramapithecus, Sivapithecus, and Brahmapithecus, they came to be collectively known as the ‘God-Apes of the Siwaliks’

• Remains of Ramapithecus were subsequently found in other parts of Asia, Africa, and Europe as well, and were dated between 10–14 mya

• Ramapithecus, who lived in the Miocene– Pliocene transition, was once thought to represent the oldest direct ancestor of modern humans

• Authenticated early human remains in South Asia are relatively recent

• In 1966, Louis Dupree discovered a fragment of a right temporal bone at the cave site of Darra-i-Kur in north-eastern Afghanistan

• The deposit in which it was found gave a radiocarbon date of 30,000 ± 1900–1200 BP i.e., 28,950 ± 1960–1235 BCE

• The fragment was considered consistent with Neanderthals as well as anatomically modern humans

• The associated stone tools seem to belong to a middle palaeolithic context

• Several cave sites in Sri Lanka—Fa Hien Lena, Batadomba Lena, Beli Lena, and Alu Lena —also yielded remains of anatomically modern humans in contexts ranging between 37,000–10,500 BP.

• More recently, hominid fossils have been found in central India. In 1982, Arun Sonakia of the Geological Survey of India made an important discovery near Hathnora village on the northern bank of the Narmada, about 40 km north-east of Hoshangabad

• Here, embedded in thick, closely packed sandy, pebbly gravel he found a fossilized fragment of a cranium (skull cap) along with some fossils of vertebrates (proboscideans and bovids) and a few late Acheulian tools

• The skull fragment seems to have belonged to a woman about 30 years old

• Sonakia suggested that she represented an advanced variety of Homo erectus —‘advanced’ because of her larger cranial capacity range of 1155 to 1421 cc— and named her Homo erectus narmadensis

• However, according to other scholars, the cranium belongs to an early (archaic) variety of Homo sapiens

• One view is that it belongs to the early part of the middle Pleistocene, beginning about 500,000 BP.

• Between 1983 and 1992, the Anthropological Survey of India launched an intensive search for human fossils and tools in the central Narmada valley

• This led to the discovery of hundreds of palaeolithic tools and some animal fossils

• In 1997, A. R. Sankhyan announced important discoveries in the same boulder conglomerate deposit at Hathnora where the cranial fragment had been found some years earlier

• These included a hominid clavicle (collar bone) along with animal fossils and several late or middle palaeolithic tools

• Estimated dates of these finds range between 0.5 to 0.2 mya

• Sankhyan suggested that the two sets of human fossils found at Hathnora may well belong to the same woman

• In 2001, P. Rajendran, a teacher in the Department of History of Kerala University, found a complete fossilized human baby skull in Odai in the Villupuram district of Tamil Nadu

• Rajendran was excavating a trench which had microliths in the upper levels and upper palaeolithic tools at the lower ones

• At a depth of 6 m, just under the upper palaeolithic deposit, there was a ferricrete deposit (a mineral conglomerate consisting of sand and gravel, cemented into a hard mass by iron oxide)

• The skull was found close to this trench, embedded in a similar ferricrete deposit which was later dated 166,000 BP, placing it in the middle or upper Pleistocene.

• The antiquity of certain other reported hominid finds is uncertain

• This is the case with the two human mandibles of an adult male and female Homo sapiens found by H. D. Sankalia and S. N. Rajaguru on the bank of the Mula-Mutha river in Pune district, Maharashtra

• The age of the mandible of an adult male found by V. S. Wakankar in a cave at Bhimbetka in Madhya Pradesh is similarly uncertain.

features of palaeo-environments • The study of the specific features of palaeo-environments is a very important part of

prehistory

• Detailed palaeo-environmental studies are so far available for very few parts of the subcontinent

• One of the earliest such studies was conducted in 1935 by H. de Terra and T. T. Paterson on the Soan (Sohan) river in the Potwar plateau, between the Pir Panjal and Salt ranges in Pakistan

• Their team found a large number of tools, mostly of the middle and upper palaeolithic, some of the lower palaeolithic as well

• De Terra and Paterson identified five tool-bearing terraces (a terrace is an old bed of a river) of the Soan and tried to correlate these terraces with the theory of a four-fold glacial cycle in Kashmir, and further, with a four-fold European glacial cycle This framework was extended, through comparisons, to the Narmada and the area around Chennai

• Although most of the correlations, sequences, and conclusions of the de Terra–Paterson study are no longer accepted, it marked an important stage in the history of prehistoric research in India

• In 1930, L. A. Cammiade and M. C. Burkitt carried out a similar study, correlating the stratigraphy of prehistoric stone tools and their environment in the Eastern Ghats of Andhra Pradesh.

• Studies of the Son valley (in northern MP) and Belan valley (in southern UP) have thrown light on the

connections between the changes in river systems, climate, and stone age sites in the valleys of these

southern tributaries of the Ganga

• During the late Pleistocene, the climate in this area was much cooler and drier than it is today. At the

same time, hippopotamus and crocodile bones show that some permanent water was available in rivers

and streams

• In the early Holocene, the climate seems to have become warmer and wetter, probably leading to an

expansion of forests and shrinking of grasslands

• The Thar desert today has very little naturally occurring surface water, except for short periods in the

rainy season, and people have to rely on rain water stored in tanks, wells, tube wells, and canals

• A study of the western Rajasthan section of the Thar desert especially around Didwana in Nagaur

district, indicates that the present environment of the Thar is very different from what it was like in the

Pleistocene era

• Except for a phase in the upper Pleistocene (25,000–13,000 BP), during most of that era, surface water in

some quantity was always available; the flora and fauna was as a result much more abundant than it is

today

• The sediments of the salt lakes indicate a significant increase in rainfall in the mid-Holocene (6,000–

4,000 BP) It is not a coincidence that the most widespread prehistoric occupation in this area belongs to

that period

Classifying The Indian Stone Age

Historical Perceptions and The Stone Age • The idea that there was an age of stone tools, followed by one dominated by those of bronze

and then of iron—was first put forward in the late 18th and early 19th centuries by the Danish scholars P. F. Suhm and Christian Thomsen.

• The accuracy of this theory was proved by excavations by another Danish scholar, Jacob Worsaae

• The next important step was to identify changes within the stone age

In 1863, John Lubbock divided the stone age into two parts

1. Palaeolithic

2. Neolithic

• A few years later, Edouard Lartet suggested the division of the palaeolithic into

1. lower palaeolithic

2. Middle palaeolithic On the basis of changes in fauna associated with the different

3. Upper palaeolithic tool types

• Archaeologists gradually identified distinct tool-making traditions within the palaeolithic and also recognized the significance of changes in subsistence patterns within the stone age.

• The use of the term mesolithic is relatively recent

Division of Indian Stone Age 1. Palaeolithic On the basis of 2. Mesolithic geological age, the type and technology of

stone tools, 3. Neolithic and subsistence base A general time range : Lower palaeolithic ---- from about 2 mya to 100,000 years ago Middle palaeolithic ---- from about 100,000 to 40,000 years ago Upper palaeolithic ------ from about 40,000 to 10,000 years ago

• There is a great deal of variation in the dates for different sites

The palaeolithic cultures belong to the Pleistocene geological era the mesolithic and neolithic cultures belong to the Holocene era

Important Features of the Stone Age

Terminology Geological Age Typical Indian Stone Tool Types Main Subsistence Base

Lower Palaeolithic

Lower Pleistocene

Pebble and Core Tools like handaxes, cleavers, and chopping tools

Hunting and Gathering

Middle Palaeolithic

Middle Pleistocene

Flake tools, including those made by prepared core techniques such as the Lavallois technique

Hunting and Gathering

Upper Palaeolithic

Upper Pleistocene

Blade tools made on flakes-e.g., parallel-sided blades and burins

Hunting and Gathering

Mesolithic Holocene Microliths Hunting, gathering, fishing, with instances of animal domestication in a few places

Neolithic Holocene Celts(ground and polished handaxes)

Food production based on animal and plant domestication

LOWER PALAEOLITHIC SITES

• Palaeolithic tools have been found in almost all parts of the subcontinent

• Allchin and Allchin. Although hardly any sites have so far been discovered in the alluvial stretches of the Indus or Ganga valleys (Kalpi in UP is an exception), they have been

• identified on rocky areas within or on the margins of these valleys, e.g., in the Rohri hills in Sindh

• and the northern fringes of the Vindhyas. Sites are prolific in other parts of the subcontinent