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Friday, 18 December 2015

World History: Introduction and Human Evolution

Welcome to the first edition of World History. In this series I will be going through major events, ideas and landmarks in world history. Each successive post will have no specific day to which it will be published and we might even go a whole month before the next post gets published. By the end of the series we would have gone on a journey that will cover every corner of the globe, see the rise of religions, the fall of empires, the birth of nations and the setting of the foundations for our current world. It is a series which will encompass history, archaeology, paleontology, anthropology. paleoanthropology, biology and climatology. We will also wonder whether human civilization has actually progressed at all. Before we start it is necessary to discuss why all of this is important.

Why is knowing the past important?
As a student of history and archaeology people have occasionally questioned the purpose of my subject. They sometimes argue that other subjects are more important: biology gives us understanding of out body while chemistry creates the medicine to keep our body healthy, maths helps us create stable buildings and manage our accounts, engineering creates almost everything that we use around us and if I list all the benefits physics bring us we shall be here for a long time. History (and archaeology) is very important in our lives. Award winning author Michael Crichton once said: If you don't know history, then you don't know anything. You are a leaf that doesn't know that it is part of a tree. History allows us to understand who we are. It is integral to our culture and our society. Every year Americans celebrate Independence Day, the French celebrate Bastille Day and the British celebrate Bonfire Night just to name a few holidays with their roots in history. History allows us to understand why this is so important. History creates a shared heritage for people. Knowing history allows stops it being corrupted. People in the past have, and will continue to do so, to try and change history to suit their own needs. Knowing history stops this from happening. History defines our culture, religious beliefs, politics, society, how we speak, how we interact and what we enjoy. History's benefits may not be as prevalent as that of engineering, maths or physics but it is there nevertheless. Now to start our journey through history with someone called Toumai whose photo is below.
Coming down from the trees: 7-4.2 million years ago
The photo above is of Toumai, a Sahelanthropus tchadensis, who lived 7 million years ago in Torro-Menalla, Chad. When Toumai was alive the Earth was going through drastic climate fluctuations. From using sediment lines dating from that time climatologists have discovered that the planet was becoming both cooler and dryer. Hence forests started to become replaced by grassland. Although only his skull is known to us Toumai shows a major evolutionary adaption to this changing environment: he has a foranum magnum close to the back of the skull. The foranum magnum is a hole where your spine connects to your brain. In chimps this is close to the center of the skull. Although Toumai's foranum magnum was not at the back at the skull it was very further back compared to a chimp leading to one possibility: Toumai was partially bipedal. Chimps and apes can walk bipedally but not for very long; Toumai's skull orientation allowed much longer bipedalism. Toumai is possibly the oldest known hominin (humans and their ancestors). We now cut to the Tugen Hills, Kenya 6.2 million years ago with another ape named Orrorin tugensis. Only a few bones are known but the two femur (the thigh bone) found were longer compared to chimps and apes. This suggests a bipedal stance for Orrorin. As Orrorin was going extinct (5.8 million years ago) a new species had evolved in the Middle Awash Valley, Ethiopia: Ardipithecus kadabba. Not many bones of this species have been found but the position in what was once a forest indicates that bipedalism must have developed in forests instead of the open plains. This would have given hominins a greater ability to survive than if bipedalism had evolved in grasslands and in forests they could still use trees for cover. 4.4 million years ago Ardipithecus ramidus roamed the land but we have more fossils of this species which gives us a better insight on hominins. This species was bipedal but the ape like toes allowed the gripping of branches with ease. Ardipithecus was hence both bipedal and a tree dweller.

Australopithecus and Paranthropus: 4.2-2.5 million years ago
4.2 million years ago in Kenya and Ethiopia a new genus of hominin evolved: Australopithecus. Australopithecus anamensis lived in what is now called the East African Rift Valley (southern Ethiopia and northern Kenya) and although they still lived in trees the position of the foranum magnum suggested it was mostly bipedal. However, it is Australopithecus afarensis which most interests paleoenthropologists. This species has been made famous by the discovery of 'Lucy' , a near complete skeleton around 3.2 million years old. She showed signs of both bipedalism (such as relatively flat feet) and her ape ancestors (like a prognathic face which is a face with a protruding jaw). At Laotoli. Tanzania a series of footprints have made by Australopithecus afarensis have been found dating back 3.6 million years. They were made by three hominins (the youngest walked in the footsteps of one of the elder ones) and are pictured above. It is important to note that the footprints could only have been made by a hominin walking upright. This family unit has been described as the first nuclear family. Australopithecus was very successful as another species, africanus, was discovered in South Africa and were more robust and taller than afarensis. Both species however have been found to have used stone tools to smash bones for the marrow inside (although they mostly ate fruit as found by wear on their teeth, as discovered by Pat Shipman). Chimpanzees do this although an archaeologist named Tote has discovered that while chimps will carry the tools for only a few meters Australopithecus would carry them over 14km! Around 2.7 million years ago Australopithecus started to diverge into two paths. Australopithecus garhi from the East African Rift Valley is a prime example of this. Between 3.3-2.4 million years ago there had been a second wave of climate fluctuations creating drier environments. It is likely this which spurred Australopithecus to adopt bipadlism to better survive in savannas which were replacing forests. Living 2.5 million years ago it had a prognathic face and strong forearms but simultaneously had long femurs and human like teeth. We shall discuss one branch of the Australopithecus first: the robust Australopithecus or as they are now known as Paranthropus.  

The earliest known Paranthropus was Paranthropus aethiopicus who lived between 2.7-2.3 million years ago. They had a bony ridge (called a sagittarel crest) across the upper jaw which were used for creating a strong pressure perfect for chewing. Parantropus had diverged from the other group of Australopithecus to become adapted at eating vegetation like modern day gorillas. There were two more species of Paranthropus, boisei and robustus, who both went extinct 1.2 million years ago. The intense climate fluctuations meant that forests, and hence vegetation, were shrinking in Africa so a specialized hominin like Paranthropus could not adapt. However, the other group Australopithecus evolved into a genus much more adaptable.

The first members of the Homo genus: 2.4-1.4 million years ago
As Paranthropus became specialized in eating vegetation another group of Australopithecus became adapted in a different way at Olduvai Gorge, Ethiopia. 2.4 million years ago our direct ancestors Homo habilis had arrived. This species was taller than Australopithecus at 1.3m (quite tall for the time) and were more intelligent with a brain size of 650 cubic centimeters. They still had many similarities with their Australopithecus ancestors with a prognathic face and thanks to analysis done by Pat Shipman on their teeth their diet consisted mostly of fruit. However there were increasing similarities to our species. They had increased meat in their diet. At Olduvai Gorge there have been butchered bones of an extinct elephant called Deinotherium which was originally used to show that our ancestors had started hunting by 2.4 million years ago. Recent analysis has found that they had actually scavenged with archaeologist Robert Blumenschine hypothesizing that in the wet season they would eat fruit while in the dry season they would scavenge. Homo habilis also created tools which have been called the Oldowan tool industry. It consisted of chipped stones which could be used for a variety of means such as cracking open bones or chipping other rocks to make tools. When Homo habilis lived the Earth started a phase of climate fluctuations which went from extremely dry to hot and wet. The Earth's orbit even changed in what is called the Milankovitch cycle which caused mass fluctuations with world temperatures. Due to Homo habilis's varied diet, tool usage and the ability to move long distances thanks to longer legs they thrived while the Paranthropus dies out. Leslie Aiello and Peter Wheeler have suggested that the addition of meat to the diet allowed the development of a bigger brain; less time was devoted to digestion of tough plant matter giving more time to allow brain development. The upright stance also allowed the development of sweat glands and a more spread out digestive system making adaptation to fluctuating climates easier.

Homo habilis lived for the most part with another species, Homo rudolfensis. This species found at Koobi Fora lived from 1.9-1.8 million years ago and were both taller and smarter than habilis with a brain size of 775 cubic centimeters. This year it has been announced that at the Rising Star Cave system in South Africa a new species has been discovered: Homo naledi. It is difficult to determine the age of naledi due to the main dating techniques (radiocarbon and potassium-argon dating) not being applicable in this instance. They have been put at around 2.8-2.5 million years ago. Unlike habilis they had more ape-like features such as the shoulder blades. 

Homo erectus: 1.89 million years ago-143 thousand years ago
In east Africa 1.89 million years ago lived the Nariokotome Boy. He was a member of the new species Homo ergaster which has now been discovered to be the same species as Homo erectus which shall be used here. Homo erectus was an immensely successful species and managed to inhabit Africa, Asia, the Middle East, Georgia and possibly even southern Spain. Homo erectus had a brain size of between 875-1000 cubic centimeters and had many similarities with modern humans. They had a hip like we do, femurs which were longer than their upper arms and flat feet. They also had larynxes which were further down the throat. In chimps the larynx is high but in humans it is low (which enables us to speak) and Homo erctus had a larynx close to where a human larynx is. It is possible that erectus had some form of language. Homo erectus also had a wide range of technological advances. First there was the Acheulean hand axes, instead of the Oldowan choppers they had axes created by chipping stones. 800,000 years ago they may have tamed fire. At Gasher Benet Ya-aqov, Israel the earliest known hearths have been found. 1.2 million years ago a hominin using Oldowan tools with a brain size of 1000 cubic centimeters lived in Gran Dolina, Spain. Some claim it is a new species of human named Homo antecessor while others claim it is Homo erectus. Whichever species it is they were very successful managing to trap small animals like rabbit and deer for food. However human bones have been found cracked open scattered among the animal bones which some have suggested shows signs of cannibalism...

The successors of erectus: 700-200 thousand years ago
While erectus were around a new species evolved solely using Acheulean hand axes. Originating in Africa they soon spread to Western Asia and Europe. They were called Homo hiedelbergensis. They were very smart at 1200-1325 cubic centimeters and were fairly close to our species in looks. They had a flat face with a chin forming and had noticeable brow ridges. In England they hunted deer with spears, built temporary shelters and saw immense cognitive development. At Twin Rivers, Zambia 250 thousand years ago they had used stones smeared in pigment to rub onto other stones to communicate and at Atapuerca, Spain they may have even buried their dead! 200,000 years ago they had vanished entirely. The population in Europe and Asia however evolved into a species that we all know: Neanderthals.

Neanderthals evolved 400,000 years ago and are nothing like the brutes commonly depicted in the media. They were smart with a brain that was even larger than our species (although we have greater cognitive abilities), they were the first species to create clothing and they are known to have cared for one another. Trinkaus and Zimmerman did research on a Neanderthal buried (showing at least some care for their dead) in Shanidar, Iran. He had a short right arm from possibly a childhood nerve damage and a blow to his right eye which left him blind in that eye. He lived many years after both of these injuries. This shows that Neanderthals cared for one another. The fact that he was buried as well shows that they must have some knowledge of an afterlife. Neanderthals were also adapt at making tools, called Mousterian which had axes and flints flaked off with a stone already specialized to do such a task. They made jewelry out of shells and would hunt by leading prey like mammoths and rhinos off of cliffs or into ravines where they would be stoned to death. Neanderthals were remarkably similar to humans in physiology bar a few differences. They had large noses to breath better in the cold Ice Age climates, they were shorter, had little sexual dimorphism, stockier and incredibly muscular. The average Neanderthal had the same physique as the Rock or Arnold Schwarzenegger in the 1980s. They also led violent lives, an average Neanderthal had as many injuries as a rodeo rider and few lived past thirty. Meanwhile in Kenya 200,000 years ago a new hominin had arrived: us.

Sapiens: 200,000-10,000 years ago
200,000 years ago Homo sapiens had evolved. Our specific species (Homo sapiens sapiens) would not arrive until 150,000 years ago when the other type of our species (Homo sapiens idaltu) went extinct. Despite almost going extinct around 90,000 years ago our species went out to conquer the world. There are contriving theories about how this happened: some argue that all humans evolved in Africa and then left, others argue we all evolved independently from erectus and hiedelbergensis, others that we hybridized with local human species while others say we assimilated with local humans. Regardless of what happened Homo sapiens spread outwards. By 60,000 years ago they had reached Asia and within the next 20,000 years they had dispersed into Indonesia, across the Sahul land bridge into Australia, Africa and Europe. Burials at Lake Mungo in Australia 40,000 years ago shows by that time they had integrated themselves. In Europe they had came into contact with Neanderthals and have been known to breed with each other thanks to a young hybrid found at Vindya, Croatia. However 40,000 years ago the climate was changing causing the animals that Neanderthals hunted to vanish and through competition with Homo sapiens (who had better technology and possibly even domesticate dogs as hypothesized by Pat Shipman, although this is tenuous) they could not adapt and vanished. 17,000 years ago the recently discovered Homo floriensis in Indonesia likely vanished for the same reason. There is considerable debate about when humans dispersed into the Americas but we know it has to be before 10,500 years ago. Through DNA cross-referencing of a Native American child who died thousands of years ago there is some traces of genetic similarity with modern day Siberians indicating that they must have come over the Bering strait while it was one continuous land mass. These early Americans would be the ancestors of the Clovis people characterized by their bifacial points (see the image below).

Our species around the world went through a massive leap in behavior and technology. As early as 35,000 years ago at Chauvet Cave our ancestors were painting extremely detailed paintings whose meaning we still have no clue about, bearing in mind the more famous Lascaux paintings were done 15,000 years ago. Earlier still at Apollo 11 Rock Shelter, Namibia 60,000 years ago permanent painting was done on the walls. 35,000 years ago in Europe (called the Gravettian) at Dolni Vestonice, Czech Republic the famous Venus figurines were being made which many have assumed to have religious significance and roughly the same time at Hohlenstein-Stadel an anthropomorphic lion statuette had been carved out of ivory possibly indicating a deity. As human technology and cognitive ability increased so did their curiosity about the world. Eventually they would start taming wild animals and planting seeds. After conquering all the world from the Amazon to Australia to Egypt to China humans would start doing a practice which many have defined civilization by since: agriculture. 

Thanks for reading. Next time we'll be talking about the origins of agriculture and how the concept of civilization is a more tricky concept than we generally believe it to be. The sources which I have used (and which you might want to read) are as follows: http://humanorigins.si.edu/evidence/human-evolution-timeline-interactive, Exploring Prehistoric Europe and The Human Past by Chris Scarre, The Prehistory of the Mind by Steven Mithen, Images of the Ice Age by Paul Bahn and Jean Vertut, People of Earth: An Introduction to World Prehistory and World Prehistory: A Brief Introduction by Brian Fagan, In Search of Neanderthals by Clive Gamble and Chris Stringer and Prehistoric Venuses: Symbols of Motherhood or Womanhood? by Patricia Rice (1981) in the Journal of Anthropological Research, Vol. 37, Article 2. Now I'll leave you with some art made by our ancestors.
The lions of Le Cabinet des Felines from Lascaux, 15,000 years ago
An auroch and other animals from Lascaux
The Lascaux unicorn
Rhinos from Chauvet cave, 35,000 years ago. In firelight the way they were painted would resemble movement.
Figures from Bradshaw rock, Australia, 17,000 years ago
The Hohlenstein-Stadel Lion Man

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