Tuesday, December 20, 2016

Migration is not Something New

Early Skulls
Until recently, the earliest evidence archaeologists had for human occupation in Ireland was dated to around 8000 BC. However, scientists have recently dated a fragment of butchered bear bone from a cave in County Clare to 10,500 BC, thereby, pushing back the date for human settlement in Ireland by 2,500 years. At a time of mass migration in the world it is, perhaps, timely to consider our origin as a species and how humans went on to inhabit the globe.
Humans and chimpanzees are very closely related and separated about 7.4 million years ago.  There is only a 1% difference between the chimpanzee genome and our own suggesting that we have a common ancestor.
Today, modern humans or Homo sapiens, inhabit the whole earth. Looking back over the last half a million years, the picture was much more diverse, with three distinct lineages appearing: Homo erectus in Asia; and Homo heidelbergensis giving rise to Homo neanderthalensis in Europe and Homo sapiens in Africa.
Image of Neanderthal Man
The Neanderthals thrived in Europe for around 300,000 years before modern humans arrived. The reason for the demise of this successful species remains a mystery. Neanderthals occupied Europe for at least 100,000 years during a period when glacial cycles dominated the climate. Excavations in Ibex, Vanguard, and Gorham’s Caves in Gibraltar have revealed evidence of Neanderthal occupation dating to possibly as late as 28,000 years ago. This makes Gibraltar the most recent Neanderthal occupation site yet discovered.
By 200,000 years ago, many innovations had been made in stone tool technology. For example, large handaxes became less common and were replaced with a range of smaller tools in more diverse toolkits. Tools made of flakes were favoured over large cores. Humans use tools to a much higher degree than any other animal and are the only existing species known to build fires, cook their food, wear clothes, and create art.
The first fossil evidence for any modern humans outside Africa comes from the Middle East, from  the archaeological sites of Skhul and Qafzeh in Israel, dating to around 120,000 years ago. However, this early expansion of modern humans was not maintained. A change to a colder climate may have driven those pioneers back into Africa. The expansion of our own species out of Africa that eventually led to the colonisation of the globe would start later – after 100,000 years ago.
Map showing the spread of humans
This dispersal out of Africa is believed to have started from Northeast Africa. Modern humans later spread worldwide, replacing earlier ancestors either through competition or interbreeding. They inhabited Eurasia (Europe and Asia) and Oceania (a region centred on the islands of the tropical Pacific Ocean) 40,000 years ago, and the Americas at least 14,500 years ago.)
Around 50,000 years ago, an improvement in the global climate, leading to the appearance of habitable lands where once there was desert, may have provided the opportunity for modern humans to spread into Europe.  Evidence from early modern human sites in Europe suggest that these early people moved into the continent along coasts and rivers, as they had done elsewhere.
Until about 10,000 years ago, humans lived as hunter-gatherers living in small nomadic groups, often in caves. Agriculture began independently in many parts of the world with different domesticated species. Hunter-gatherers already knew a great deal about plants and animals and often manipulated them or the environment to increase productivity. Farming entered Europe around 7000 BCE and was the main way of life across Europe by 4000 BCE.
Farming communities spreading into Central Europe around 5600 BCE had to adapt to bitter winters, heavy rainfall, and dense forests. They kept mainly cattle and farmed open river terraces. Farming spread through Western Europe and into other parts of Central, Northern, and Eastern Europe by 4000 BC.  Animals were initially kept for meat, hides, bones, and manure. Feeding animals on crop surpluses made them a food reserve, and large herds signified wealth and prestige. Domestic animals became far more important when people began using them also in other ways: for milk, wool, eggs, traction, and transport.
Examples of early metal working
The social importance of metals for making prestige objects with which people could show their status, led to the early development of metallurgy. Only later, with the development of alloys, did metal also become significant as a material for tools and weapons. Smelting copper and lead ores began in West Asia after 7000 BC, and by the sixth millennium BC casting was possible. By 2500 BC, metallurgy had spread through Europe. Bronze-working became widespread after 1800 BC with trade routes linking much of the continent circulating metals, particularly tin.
Prehistoric religion reflected people’s need to understand the world and explain disasters. Through rituals and offerings ancient societies sought to bribe or appease the divine forces controlling the world or its individual components. Since Neanderthal times, people have practised rites that showed concern for their dead, perhaps linked to a belief in an afterlife.
Newgrange Stone Age Passage Tomb
Burial in graves or tombs or under house floors, was common. Many societies practised other rites, including cremation, exposure, or disposal in watery places. Some thought it important to preserve the body and undertook mummification (for example, in Egypt and South America). Monumental tombs, such as tumuli, pyramids, and megaliths, could link the living and the dead to ancestral lands or sacred places.  
Humans and chimpanzees are very closely related and separated as recently as about 7.4 million years ago. Our ancient cousins, the Neanderthals thrived in Europe for around 300,000 years before modern humans arrived and may have survived until around 28,000 years ago. Innovation in stone tool technology aided the development and eventual spread of modern humans throughout the globe. Later developments in metal working and agriculture assisted this dispersal. Since Neanderthal times, people have practised rites that showed concern for their dead, perhaps linked to a belief in an afterlife.

Migration is not something new and, in a sense, we are all migrants whose ancestors were black and lived in Africa a long long time ago.

Further reading: Evolution - The Human Story (2011) by Dr.Alice Roberts
See also BBC DVD The Incredible Human Journey

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