The beginning of the last Ice Age…
132237 BCE to 111502 BCE
The beginning of the last Ice Age is conventionally dated at about one hundred and twenty thousand BCE with the onset of the Abbassia Pluvial, an extended wet and rainy period in the climate history of North Africa.
The Abbassia Pluvial, which lasted approximately thirty thousand years, and ended around ninety thousand ybp, spanned the end of the Lower Paleolithic and the start of the Middle Paleolithic eras—an interval that is also sometimes identified as the Acheulean (two hundred and fifty to ninety kybp).
As with the subsequent Mousterian Pluvial (circa fifty to thirty kybp), the Abbassia was brought about by global climate changes associated with the ice ages and interglacials of the Pleistocene Epoch.
Like the Mousterian Pluvial, the Abbassia Pluvial brought wet and fertile conditions to what is now the Sahara Desert, which bloomed with lush vegetation fed by lakes, swamps, and river systems, many of which later disappeared in the drier climate that followed the pluvial.
During this period, African wildlife now associated with the grasslands and woodlands south of the Sahara penetrated the entire North African.
Human Stone Age cultures—notably the Mousterian and Aterian Industries—flourished in Africa during the Abbassia Pluvial.
The shift to harsher climate conditions that came with the end of the pluvial promoted the emigration of modern Homo sapiens out of Africa and over the rest of the globe.
This was the third wave of the Sahara pump cycle.
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The beginning of the last Ice Age is conventionally dated at about 120,000 BCE.
The Eemian, an interglacial period which begins about one hundred and thirty thousand years ago and ends about one hundred and fourteen thousand years ago, is the second-to-latest interglacial period of the current Ice Age, the most recent being the Holocene which extends to the present day.
The prevailing Eemian climate is believed to have been about as stable as that of the Holocene.
Changes in the earth's orbital parameters from today (greater obliquity and eccentricity, and perihelion), known as the Milankovitch cycle, probably lead to greater seasonal temperature variations in the Northern Hemisphere, although global annual mean temperatures are probably similar to those of the Holocene.
The warmest peak of the Eemian is around one hundred and twenty-five thousand years ago, when forests reach as far north as North Cape (which is now tundra) in northern Norway well above the Arctic Circle.
Hardwood trees like hazel and oak grow as far north as Oulu, Finland.
At the peak of the Eemian, the northern hemisphere winters are generally warmer and wetter than now, though some areas are actually slightly cooler than today.
The hippopotamus is distributed as far north as the rivers Rhine and Thames.
Trees grow as far north as southern Baffin Island in the Canadian Arctic Archipelago instead of only as far north as Kuujjuaq in northern Quebec, and the prairie-forest boundary in the Great Plains of the United States lies further west—near Lubbock, Texas, instead of near Dallas, Texas, where the boundary now exists.
Sea level at peak is probably four to six meters (thirteen to twenty feet) higher than today (references in Overpeck et al., 2006), with much of this extra water coming from Greenland but some likely to have come from Antarctica.
Global mean sea surface temperatures are thought to have been higher than in the Holocene, but not by enough to explain the rise in sea level through thermal expansion alone, and so melting of polar ice caps must also have occurred.
Because of the sea level drop since the Eemian, exposed fossil coral reefs are common in the tropics, especially in the Caribbean and along the Red Sea coastlines.
These reefs often contain internal erosion surfaces showing significant sea level instability during the Eemian.
A 2007 study found evidence that the Greenland ice core site Dye 3 was glaciated during the Eemian, which implies that Greenland could have contributed at most two meters (6.6 feet) to sea level rise.
Scandinavia was an island due to the inundation of vast areas of northern Europe and the West Siberian Plain.
Given that the shorelines of the islands of the present are at this time several feet higher, humans of this epoch must have used boats: the large island of Crete in the Aegean basin is settled as early as 128,000 BCE, during the Middle Paleolithic age.
The period closes as temperatures steadily fall to conditions cooler and drier than the present, with four hundred and sixty-eight-year long aridity pulse in central Europe, and by one hundred and fourteen thousand years before the present, a glacial era has returned.
The fragments of a Neanderthal skull disinterred from a deposit of limestone at the Ehringsdorf quarries along the Ilm River, roughly two point four kilometers from Weimar, Germany, is known as the Ehringsdorf skull.
The deposits in which this skull were found came from the travertines belonging to the second half of the last (Eemian) interglacial period.
The estimated age of the remains are one hundred and fifty thousand to one hundred and twenty thousand years.
German anthropologist Franz Weidenreich will publish a monograph on the subject in 1928, titled Der Schädelfund von Weimar-Ehringsdorf, where he will describes it as the skullcap of an adult female.
His suggestion that the frontal area of the remains showed evidence of being struck leads to the conclusion that the subject was murdered.
In addition, he determined that the lack of a cranial base meant the skull had been opened for the purpose of extracting the brain.
However, the remains are so fragmentary that little attention was paid to this opinion.
Scottish anthropologist Arthur Keith made a study of the skull in 1931, concluding that it belonged to an individual less than twenty years old.
Although classed as an early Neanderthal type, the skull bears some features found in the species Homo sapiens.
In particular, it has a rounded occipital bone.
It is believed that the area was on the route out of Africa that some scholars suggest was used by early humans to colonize the rest of the Old World.
In 1999, the Eritrean Research Project Team, composed of Eritrean, Canadian, American, Dutch and French scientists, will discover a Paleolithic site with stone and obsidian tools dated to over one hundred and twenty-five thousand years old near the Bay of Zula south of Massawa, along the Red Sea littoral.
The tools are believed to have been used by early humans to harvest marine resources like clams and oysters.
There is little evidence of human occupation in Britain during the Ipswichian Stage (Eemian Stage elsewhere) between around one hundred and thirty thousand and one hundred and ten thousand years ago.
Meltwaters from the previous glaciation cut Britain off from the continent during this period, which may explain the lack of activity.
Overall, there appears to be a gradual decline in population between the Hoxnian Stage and this time suggesting that the absence of humans in the archaeological record here was is the result of gradual depopulation.
Lice have been the subjects of significant DNA research that has led to discoveries on human evolution.
For example, recent DNA evidence suggests that pubic lice spread to humans approximately two million years ago from gorillas.
Additionally, the DNA differences between head lice and body lice provide corroborating evidence that humans started losing body hair, also about two million years ago.
Genetic analysis suggests that the human body louse may have originated about one hundred and seven thousand years ago from the head louse after the invention of clothing, with the ancestor of all human lice emerging about seven hundred and seventy thousand years ago.
New, local tool traditions, including the Mousterian, appear in the frigid environment of glacial western Asia and Europe, as human populations begin to exploit a variety of habitats.
Mousterian toolmakers, including the Neandertalers, ingeniously adapt their implements to a wide variety of tasks: cutting and preparing meat, scraping hides, working wood, and many others.
Mousterian tools found in Europe and made by Neanderthals date from between 300,000 BP and 30,000 BP.
They are also produced by anatomically modern humans in Northwestern Africa and the Near East.
Assemblages produced by Neanderthals in the Levant, for example, are indistinguishable from those produced by Qafzeh type modern humans.
It may be an example of acculturation of modern humans by Neanderthals, because the culture after one hundred and thirty thousand years reaches the Levant from Europe (the first Mousterian industry appears there 200,000 BP) and the modern Qafzeh type humans appear in the Levant another hundred thousand years later.
The Moderns are taller, more slender, and less muscular than the Neanderthals, with whom they share—perhaps uneasily—the Earth.
Though their brains are smaller in overall size, they are heavier in the forebrain, a difference that may allow for more abstract thought and the development of complex speech.
Yet, the inner world of the Neanderthals remains a mystery—no one knows the depths of their thoughts or how they truly expressed them.
In human genetics, Y-chromosomal Adam (Y-MRCA) is the most recent common ancestor (MRCA) from whom all living people are descended patrilineally (tracing back only along the paternal lines of their family tree)
Recent studies report that Y-chromosomal Adam lived as early as around one hundred and forty-two thousand years ago: older studies estimated Y-MRCA as recent as sixty thousand years ago.
Mitochondrial Eve in the field of human genetics refers to the matrilineal most recent common ancestor (MRCA) of modern humans.
She, in other words, is the woman from whom all living humans today descend, on their mother's side, and through the mothers of those mothers and so on, back until all lines converge on one person.
Because all mitochondrial DNA (mtDNA) is generally passed from mother to offspring without recombination, all mitochondrial DNA (mtDNA) in every living person is directly descended from hers by definition.
Each ancestor (of people now living) in the line back to the matrilineal MRCA had female contemporaries such as sisters, female cousins, etc., and some of these female contemporaries may have descendants living now (with one or more males in their descendancy line), but none of the female contemporaries of the "Mitochondrial Eve" has descendants living now in an unbroken female line.
The foundation population of the humans that today inhabit the world are the survivors of what appears to be an evolutionary bottleneck caused by a global catastrophe during the period that begins around 90,000 BCE.
The Toba supereruption (Youngest Toba Tuff or simply YTT), a supervolcanic eruption that occurs some time between sixty-nine thousand and seventy-seven thousand years ago at Lake Toba in Sumatra, Indonesia, is recognized as one of the Earth's largest known eruptions and is the most closely studied supereruption.
The related catastrophe hypothesis holds that this event plunged the planet into a six-to-ten-year volcanic winter and possibly an additional one thousand-year cooling episode.
This change in temperature results in the world's human population being reduced to ten thousand or even a mere one thousand breeding pairs, creating a bottleneck in human evolution.
Consistent with the Toba catastrophe theory, evolutionary biologist Richard Dawkins has postulated that human mitochondrial DNA (inherited only from one's mother) and Y chromosome DNA (from one's father) show coalescence at around one hundred and forty thousand and sixty thousand years ago, respectively.
In other words, all living humans' female line ancestry traces back to a single female (Mitochondrial Eve) at around one hundred and forty thousand years ago.
All humans can trace their ancestry with certainty via the male line back to a single male (Y-chromosomal Adam) at ninety thousand to sixty thousand years ago.