The Human Journey

The Human Journey

Humans left genetic footprints when they first ventured out of Africa that are still visible today. It is by mapping these genetic markers in modern peoples, that a picture is created of where and when ancient humans have moved around the world. These great migrations eventually led the descendants of a small group of Africans to occupy the farthest reaches of the Earth.

Homo sapiens or modern humans have spent the majority of their time on Earth in Africa. The earliest known archeological evidence is found in Ethiopia, which suggests our species is approximately 200,000 years old. From 160,000 years ago and over the course of the next 25,000 years, three hunter-gatherer groups travelled from East Africa south to the Cape of Good Hope, south-west to the Congo Basin and west to the Ivory Coast to occupy all of the African continent. Temperatures at this time remained at approximately 7 to 8 degrees cooler than average temperatures today. This expanded North African deserts and is believed to have created a natural barrier to migration out of Africa.

Then between 135,000 – 115,000 years ago, after relatively abrupt warming that led to the melting of the ice caps, another group travelled across a then lush green Sahara, up the Nile River to Israel. This was the first human group ever to have left the original continental African birthplace of humanity. However this group died out by 90,000 years ago due to a global freeze-up which turned North Africa into extreme desert once again. This event shows how fragile our existence can be and how climate change can make massive impacts on our existence.

Then approximately 74,000 years ago, the super-eruption of Mt. Toba in Sumatra caused a six year long nuclear winter and an instant thousand year long Ice Age. Genetic evidence points to a sharp reduction in human population sizes around this time to fewer than 10,000, and some research indicates that Homo Sapiens may have been reduced to as few as 2,000 individuals. We were on the verge of extinction.

At around 70,000 years ago, the climate became wetter and stabilized. Human populations expanded and our ancestors left Africa for a second time between the Red Sea and the Gulf of Aden. Humans made the short sea voyage and landed in the Middle East. Incredibly, all non-African peoples are descended from this single, small band of individuals. This group then travelled as beach combers along the southern coast of the Arabian Peninsula towards India. From Sri Lanka they continued along the Indian Ocean to western Indonesia, which was then a landmass still attached to Asia. Still following the coast they moved around Borneo to Southern China. Groups also reached New Guinea and Australia by land bridges and boats by 50,000 years ago.

Dramatic warming of the climate 52,000 years ago meant groups were finally able to travel inland following rivers into Europe for the first time and more extensively into Asia. By 40,000 years ago, human groups had reached Spain while other Asian groups made more penetrative migrations into central Asia, Korea and Japan. Over the course of the next 15,000 years, human groups pushed from central Asia into Eastern Europe and north into the Arctic Circle and Siberia. Homo Sapiens were able to adapt to the Ice Age weather and somehow survived in these far northern areas. The Neanderthals, whom Homo Sapiens had been interacting with since their first exit from Africa, were finally wiped out by the more advanced modern human beings around 20,000 years ago.

Between 25,000 and 22,000 years ago, great ice sheets covered the far north of our world and sea levels were approximately 90 metres lower than they are today. This exposed a huge tract of land that connected Asia to the Americas. This allowed Asian hunters, ancestors of the Native Americans, to migrate across the Bering land bridge connecting Siberia to Alaska, either passing through the ice corridor or taking the coastal route into North America for the first time. The Ice Age reached its coldest between 19,000 to 15,000 years ago with temperatures 9 to 10 degrees below today's average temperatures. In Northern Europe, Asia and North America, this ‘glacial maximum’ caused a de-population in the most northern regions of these continents, with isolated surviving groups locked in refuges. In North America the ice corridor closed and the coastal route there froze over. The groups that were isolated  continued expanding into South America and they made it all the way to the tip of South America in a very short time. At the end of the last Ice Age, 12,500 to 10,000 years ago, reoccupation of North America occurred, before the continent finally became cut off from Asia. Warmer temperatures led to rise in the sea level which meant other groups of humans found themselves isolated on islands. The final collapse of the Ice Age by 8,000 years ago allowed the recolonisation of Britain and Scandinavia. 

After the last Ice Age, the world’s climate stabilised and the total world population is believed to have numbered a few million people. Until this point, modern humans had been foragers and hunters but with the advent of a stable environment, humans began to settle down. The area between the Tigris and Euphrates rivers and around the Nile River Delta is thought to be the birthplace of agriculture, though recent research suggests that the advent of agriculture may have taken place in several locations independently in the Americas and Africa. Around this time the domestication of animals began. The rise in human civilisations resulted in massive changes to human behaviour and a population explosion to some 300 million by 2000 years ago.

Written by: Matt Kershaw

References:

• Bradshaw Foundation. 2003, Journey of Mankind: peopling of the world, viewed on Dec 9^th 2013, <http://www.bradshawfoundation.com/journey/> 
• Institute for the Study of Human Knowledge. 2012, The Human Journey, viewed on Dec 9^th, 2013, <http://www.humanjourney.us/northEast.html> 
• National Geographic Society. 2013, The Human Journey: migration routes, viewed on Dec 9^th, 2013, <https://genographic.nationalgeographic.com/human-journey/>
  
• Yirka, B. 2013, New Study Refutes Claims of Early Humans in India Prior to Mount Toba Eruption, viewed on Dec 9^th 2013, <http://phys.org/news/2013-06-refutes-early-humans-india-prior.html>

The Black Death

The Black Death

A series of natural disasters, droughts, earthquakes and floods in China from 1333 to 1345 was followed by locust swarms, famine and pestilence. By the end of 1346, it was widely known in the major European seaports that a plague of a previously unheard of magnitude was raging in the East.  This plague or The Black Death was probably carried first along the Silk Road and then from Constantinople by rat fleas living on the black rats that were regular passengers on merchant ships trading throughout the Mediterranean.

The plague was reportedly first introduced to Europe in 1347 at the trading city of Caffa in the Crimea in Eastern Europe. The city was under siege by the Mongol army who were suffering from the disease. The Mongols catapulted infected corpses over the city walls to infect the inhabitants. When the traders fled the city, they took the plague by ship into Sicily and the south of Europe, where it then spread to the rest of continental Europe.

From Italy, the Black Death spread to France where in Marseilles it’s reported that 50 to 60% of the city’s population died, and then onto England in 1348, where in London half the population perished. By mid-1349 the plague had reached Germany, followed by Scandinavia and northern Scotland at the end of that year, and then onto Russia by the end of 1350. Then for some unknown reason the pandemic halted.

The plague presented itself in three various forms. With the bubonic variant which was the most common, swellings (buboes) appeared on a victim's neck, armpits or groin. These tumors could range in size from that of an egg to that of an apple.  The victim had a life expectancy of up to a week. A second variation, pneumonic plague, attacked the respiratory system and was spread by simply breathing the exhaled air of a victim. Life expectancy was measured in only one or two days. Finally, the septicemic version of the disease attacked the blood system.

As the plague hit with such devastating fury, people tried to make sense of what the disease was. Some people believed that the planets were responsible for the plague when the coming together of planets was a sign of terrible or violent things to come. Others believed invisible fumes or poisons could kill people from either looking at each other or merely breathing air in. Another belief, in particular with highly religious people of those times, was that God or the Devil was the cause of all of their problems. Having no defense and no real understanding of the cause of the plague, the men, women and children caught in its path were baffled, panicked, and finally devastated.

The sick, regardless of their position in society were abandoned by family and those closest to them. However it was the poorest that suffered the most as they received no attention or care. Many ended their lives in the streets while many others who remained and died in their homes were only known to be dead because the neighbours smelled their decaying bodies. Dead bodies filled every corner of villages, towns and cities, and such was the multitude of corpses that mass graves were dug in church cemeteries by those concerned to get rid of their rotting bodies.

'This epidemic... kills almost instantly, as soon as the airy spirits leaving the eyes of the sick man has struck the eye of a healthy bystander looking at him, for then the poisonous nature passes from one eye to the other.

The plague was especially deadly as it ravaged crowded European cities. Here is an account from one in Siena, Italy:

They died by the hundreds, both day and night, and all were thrown in … ditches and covered with earth. And as soon as those ditches were filled, more were dug. And I, Agnolo di Tura … buried my five children with my own hands … And so many died that all believed it was the end of the world.

While the humanist Giovanni Boccaccio witnessed the Black Death in Florence:

Such was the cruelty of heaven and, to a great degree, of man that, between March [1348] and the following July, it is estimated that more than 100,000 human beings lost their lives within the walls of Florence, what with the ravages attendant on the plague and the barbarity of the survivors towards the sick.

The Black Death reduced the world population from an estimated 450 million to between 350 and 375 million in the 14th century. It was particularly devastating in Europe, killing between 30 to 60% of the population. Population levels in Europe then took 150 years to fully recover to their pre-plague levels. The aftermath of the plague created a series of huge social, economic and religious upheavals, which had profound effects on the course of European history.

Written by: Matt Kershaw

References:

• Alcon, S.A. 2003, A Pest in the Land: new world epidemics in a global perspective,  The Univeristy of New Mexico Press, USA.
• Channel 4 – History. 2008, The Black Death, viewed on Aug 23^rd 2012, <http://web.archive.org/web/20080625094232/http://www.channel4.com/history/microsites/H/history/a-b/blackdeath.html>
• EyeWitness to History. 2001, ‘The Black Death, 1348’, viewed on Aug 23^rd 2012, <http://www.eyewitnesstohistory.com/plague.htm>
• Ziegler, P. 2009, The Black Death, Harper Perennial, New York.