What is an Orcadian ?

This article proposes that our evolution as a distinct genus and particular sub-species has been driven by large scale Climate Change, which in turn has been driven by catastrophic tectonic events allied with recurring glacial Ice advances over the past two million years. I believe the timelines as described are accurate. Any conjecture is mine. Many links could be added but I suggest you seek your own sources if the topic interests you.

In the Palaeocene epoch, around 65 million years ago Proto Prosimians first appear in the geological record. This obscure mammalian branch watched over the death of the dinosaurs and the destruction of a global ecosystem.

Debate continues, but this catastrophe was most likely caused by a series of meta-destructive events taking place over hundreds of thousands of years. The Chicxulub asteroid impact event of the Yucatan being the most high profile, but a far more probable culprit being the incomprehensibly vast, in time and space, vulcanism which created the continental flood basalt’s of the Indian Deccan Traps. Whatever the cause (s) the face of the planet was altered for ever.

One ecosystems catastrophe is another ecosystems opportunity, and evolution, without so much as a backward glance, radiated chaotically as it always does following a mass extinction, and the mammalian age was established.

Toward the end of the Eocene, about 40 million years ago, Prosimians were a small but significant part of this radiation. Paleoclimatic data shows that coincidentally, the Earths climate slowly began to cool at this time.

The Eocene epoch was actually unusually warm,with hippopotamus living in England and alligators living north of the arctic circle.

A further 35 million years passed until about 5-7 million years ago, cooling began to accelerate, just as some of these Prosimians had successfully evolved into hominid creatures. These apes were numerous and diverse, and lived, as apes still do, in woodland and forest. This was the time of the Ape, as the earth was covered in wild wood, every possible acre, every possible square foot, was forested.

The Earth, being fickle, tweaked, and minor climate change led to a rapid deterioration in the forest. Savannah replaced jungle, and the Apes found their habitat disappearing. Planes Predators found the crouching apes easy meat and many subspecies became extinct. One sub-group walked, not gambled, out of the forest in search of a new home.

This group were upright, with pro-ambulating hip joints and pelvic girdles capable of long distance upright travel. They were able to avoid the predators well enough to reach the remaining forests, now become Islands in the planes. They were small creatures at first, described as Australopithecus but continued to evolve as others declined to become the dominant hominid group.

This sub-species further evolved and became described as Homos Habilis. The world was not done with tweaking. Not quite enough cooling change had occurred, so about 2 million year ago ago the switch was hit and cold became the dominant climatic condition, leading to the beginning of the modern Ice Age.

Somewhere in this timeline the known caldera of the mantle plume super-volcano at Yellowstone erupted, probably about 1.3-1.5 million years ago. The effects of this definite catastrophic event would have been easily enough to force the ice age cycle into overdrive.

The oxygen isotope record shows climate for the past 1.6 million years fluctuating between relatively cold glacial periods, when ice sheets grow, and warm interglacial periods, when ice sheets shrink. Although only four glaciations are evident from the record of moraines and glacial features preserved in the landscape, the oxygen isotope record shows more than 60 episodes of glacial advance over the last 2 million years.

At first, glacial and interglacial periods appear to have been of equal duration, each lasting about 50,000 years, with only a moderate difference between warm and cold climate states. This changed about 1 million years ago when glacial episodes became fewer and longer (about 100,000 years) with much shorter interglacial warm periods.

Also, the contrast between glacial and interglacial periods became more intense, with larger growth of ice sheets followed by more extensive melting during interglacials. During this time the dominant version of hominid had evolved further to be described as Homo Erectus - found widely over Africa, Asia (Java, Peking), Europe (Algeria, Germany, Greece), between 250,000 to 1.6 million years ago.

Erectus appears to be the first species to migrate out of Africa. This was the first hominid to inhabit caves and use fire.

This harsh and ever changing environment led to the rapid evolution of these upright monkeys. One mysterious physical mutation occurred again, as important as the hips that had let them walk out of the forest. The human type voice box . It is a matter of conjecture which came first; self awareness or communication with language.

But it cannot be argued that self-awareness without communication is meaningless at best and some kind of hell at worse. It is also a matter of conjecture as to at what point communication becomes language, but symbolism, or abstraction, has to be the defining facet.

Nobody, despite learned papers, dissertations and great inquiry by great minds can or ever will be likely to pinpoint when that step was taken. It can be placed in time, however, at no more than 2 million years past.

This coincidence with the start of the Ice Ages is not accidental. To survive as a flimsy ape homos needed his brain to give him the edge. Once complex messages could be communicated survival became far more certain. Planning, scouting, exploring and tool development meant all kinds of environmental, ecological or climatic bullets could be avoided. Memory was passed on, culture began.

Intelligence fed on itself as an evolutionary advantage, but it fed even more on the need to survive in a rapidly and violently fluctuating environment which was always harsh and sometimes deadly. Needs must as the devil drives.

No one knows whether Homo Erectus continued to evolve into Homo Sapiens, as there are characteristics of the forehead, jaw and teeth which are more marked than Australopithecus and not at all similar to Homo Sapiens of today. Some argue that Homo Erectus was an evolutionary line from Australopithecus which died out, and Homo Sapiens come from a different line. This is the famous "Missing Link".

Between 400,000 years ago and the second interglacial period in the Middle Pleistocene, around 250,000 years ago, the trend in cranial expansion and the elaboration of stone tool technologies developed, providing some evidence for a probable transition from Erectus to Sapiens.

250,000 years ago Homo Erectus became extinct, and Homo Sapiens Neanderthalis emerged from hominid stock in Africa (which may, or may not, be from the Erectus species).

Homo Sapiens Neanderthalis was superbly adapted to become dominant in the Eurasian super continent. Living in the tough harsh environment that the world was he was much stronger and far hardier than us and superbly adapted to living in the extreme cold tundra like margins where life survived the ice. He lived as a hunter gatherer, ambushing prey in scrubby marginal woodlands, as aboriginal Inuit on a grand scale.

It is by no means clear that Neanderthalis was alone, even before we arrived. It is certain that we shared the planet with this cousin human for all but the last 30,000 years, and given the limited resources of paleo-archaeology and scope of possibility it is actually more than likely that remnants of Neanderthalis continued well into the past 10,000 years . Between 1m and 300,000 years ago it is quite feasible that a number of other strains of Erectus subspecies existed.

The known evidence suggests that there was a migration of Erectus out of Africa, then a further speciation of Homo sapiens Neanderthals from H. Erectus in Africa.

One group did not leave at this time, evolved differently, stayed in Africa, becoming Us, Homos Sapiens Sapiens . This slightly different path was to give our forbears one critical advantage over both Erectus, Neanderthalis and any other version of hominid; Adaptability.

The Neanderthals evolution had become too specialised. Any species that evolves to become to reliant on a particular set of circumstances is highly vulnerable to change. This is a pattern repeated throughout the evolutionary record. Long lived species either find an unchanging niche or are going to be adaptable. In the case of Homo Sapiens Sapiens when he eventually left Africa, spreading along coastal margins, he rapidly out-competed the Neanderthal. It is unlikely that any contemporary form of War ever existed between the species. As Homos Sapiens Sapiens became more and more successful the resources left for the Neanderthal diminished. They dwindled, they became extinct. This is almost certainly what happened to all the previous less developed or adaptable sub-species of Homos. The harsh ice age dominated environment allowed no passengers. It was a very Darwinian process.

The most recent glacial episode (called the Wisconsin Glaciation in North America and the Wurm Glaciation in Europe) began about  115,000 years ago. From a climate very similar to that of today, perhaps slightly warmer, temperatures declined by 21,000 years ago to an average of 12F to 18F cooler. High latitude temperatures were at least 27F cooler and huge ice sheets covered northern North America, western Europe, the British Isles, and ice caps covered most mountain ranges.

In the same period, the last known super-eruption occurred. Some 74,000 years ago, in what is now Sumatra, a volcano called Toba erupted with a force estimated to have been 10,000 times that of Mt. St. Helens. The sky darkened around the globe as ash blocked out the Sun. Temperatures plummeted by as much as 21 degrees at higher latitudes around the planet, and it is thought that three quarters of the plants in the Northern Hemisphere may have died.

This event is now thought to explain a curious bottleneck in human evolution, a phenomenon observed by researchers who study DNA. The blueprints of life for all humans are remarkably genetically similar given an evolutionary timeline known to stretch back more than 2 million years.

Our ancestors, struggling as always against the elements, were pushed to the edge of extinction after the Toba eruption. Perhaps only a few thousand survived. Humans today are all be descended from these few, and in terms of the genetic code, not a whole lot of evolution occurs in 74,000 years.

This period covers the agreed history of Homos Sapiens Sapiens most exactly. Biologically modern human beings first appear about 120,000 years ago. Cro-magnon man, with prominent chin, a sharply rising forehead, and a refined skeleton were identified in France some 40,000 years ago. Cro-Magnon man was anatomically identical to modern humans. A Cro-Magnon baby would be entirely indistinguishable from any baby born today.

What makes the Cro-Magnon Hominid interesting is that he took communication onto a much higher level, using art and technological innovation to define his existence, define his reality, in exactly the same way as we do today. It was this non-productive creative sidestep that took us out of nature and into the modern world. The use of symbolism and as means of information storage and communication became Art.

The advance of man was a direct by-product of the continuos pressure to survive and evolve caused by the relentlessness of the Ice Ages, which in turn are driven by tectonic volcanic events. Once the preconditions of upright gait, a complex voice box and large brain were set in motion the rest was forged by Ice and Fire.

Although it took tens of thousands of years for the great ice sheets of the Wisconsin/Wurm Glaciation to form, they melted away in only a few thousand years.

A brief warm period, the Allerod, at 11,500 bp was followed by a short glacial re advance, the Younger Dryas, which ended abruptly with rapid warming around 10,000 years bp.

This re-advance may well have modern implications. After an initial rapid period of global warming enough ice melted to cool and shift deeply established heat exchange currents in the Oceans. This led to climate change in reverse and the ice quickly returned. Sound familiar ? Anyway, after this 1500 year mini-glaciation the ice retreated into northern Canada. By 8000 years bp North America and Europe were relatively ice free.

Sometime around then the first Orcadians walked from Caithness across the then existing land bridge and settled the land.

For the last 9,000 years of the modern interglacial climate has been relatively stable, with fluctuations in average temperature of less than 6 F. There have been four cycles of high to low temperature, with the lows referred to as little ice ages and the highs called little climatic optima. The most recent, the Little Ice Age, lasted from about 1450 to 1850 AD.

Don’t forget your thermals.