A BRIEF WIKIPEDIAN HISTORY OF TIME
I thought it'd be nice to have the chronology of human development weaved with climatic data. Here is what I could gather from wikipedia. Now we have all the relevant material in one (long) post.
Middle Paleolithic (300,000 to 30,000 years ago)
The Middle Paleolithic is the second subdivision of the Paleolithic or Old Stone Age as it is understood in Europe, Africa and Asia. During this time period Homo neanderthalensis thrived in Europe. The first humans with proto-Neanderthal traits are believed to have existed in Europe as early as 600,000–350,000 years ago.
The
Mousterian technology, starts 300,000 years ago. Widely associated with Neanderthal, Mousterian technology ends, like Neanderthal, around 30,000 ybp. Javelins were a big part of the armory. There were also axes, bifaces, scrappers and sometimes semi-light projectile heads obtained through the Levallois technique, like in the Châtelperronian culture.
The earliest anatomically modern humans also appeared during this period, around 195,000 years ago. Homo sapiens remains in Africa for most of this period, using the same technology as other human species. There are suggestions that in sub-Saharan Africa human populations dropped to as low as 2,000 individuals for perhaps as long as 100,000 years, before numbers began to increase in the Upper Paleolithic. There are also genetic indications that the population went through several bottlenecks.
The
Toba catastrophe theory suggests that a bottleneck of the human population occurred c. 70,000 years ago, reducing the total human population to c. 15,000 individuals [or 11-12,000 elsewhere in the article] when Toba erupted and triggered a major environmental change, including a volcanic winter. The theory is based on geological evidence for sudden climate change at that time and for coalescence of some genes (including mitochondrial DNA, Y-chromosome and some nuclear genes)[45] as well as the relatively low level of genetic variation among present-day humans.[44] [...] This suggests that the female line ancestry of all present-day humans traces back to a single female (Mitochondrial Eve) at around 140,000 years ago, and the male line to a single male (Y-chromosomal Adam) at 60,000 to 90,000 years ago.
According to the Out of Africa Hypothesis, modern humans began migrating out of Africa during the Middle Stone Age/Middle Paleolithic around 100,000 or 70,000 years ago and began to replace earlier pre-existent Homo species such as the Neanderthals and Homo erectus. This datation applies to modern day Israel. Setanta has pointed out that sapiens and neanderthal may have in fact coexisted in the same location at one Israeli site in or around 70,000. I cite his post:
Quote:At an archaeological site in Israel, remains of early modern man and of Neanderthals were found, showing that the Neanderthals arrived after early modern man was established at that site. The striking difference found between the two groups was in the middens. The evidence of the middens is that Neanderthals were more heavily dependent of hunting and less on foraging, and that they did not take much advantage of fish and sea food. They left evidecne of far less use of forage foods. They disappear from the site while early modern humans continued there. There were no signs of violent death. The Israeli archaeologists believe that the Neanderthal band simply was not able to sustain itself well in a region where early modern man made full use of fish, sea food and forage plants.
It's around these times, late middle paleolotic, that interbreeding would have happened between the two species. Supposedly, relations were good between two species using about the same technology. Modern Israel and the Middle East were perhaps a melting pot of sorts, aborder or no man's land separating the two species. Genetic evidence suggests that Neanderthals contributed to the DNA of anatomically modern humans, probably through interbreeding between 80,000 and 50,000 years ago with the population of anatomically modern humans who had recently migrated from Africa. According to the study,
by the time that population began dispersing across Eurasia, Neanderthals genes constituted as much as 1–4% of its genome.
Upper Paleolithic - 50/40,000 to 12,000 years ago
Something changed about 50,000 years ago, i.e. almost 150,000 years after H. sapiens appeared on the scene: a marked increase in the diversity of artifacts, first noticeable in Africa, including projectile points, engraving tools, knife blades, and drilling and piercing tools. These new tools appear rapidely, and are strongly associated in the archeological record with Homo sapiens. The new technology generated a further population explosion of modern humans which is
believed to have led to the extinction of the Neanderthals.
Three thousand to 4,000 years later, this tool technology spread with people migrating to Europe. The invaders, commonly referred to as the Cro-Magnons, left many sophisticated stone tools, carved and engraved pieces on bone, ivory and antler, cave paintings and Venus figurines. The technologies that gave Homo sapiens a strong competitive edge against Mousterian techniques and those humans who used them, including Neanderthal, and that appears circa 50,000 bp, is the next big thing:
Aurignacian, characterized by much finer tools and weapons, allowing lighter projectiles (arrows or smaller spears) and all sorts of things made from ivory or bones: fishing hooks, needles, spearthrowers, statuettes, etc. As I have pointed out, the combination of spearthrowers and lighter missiles gave our ancestors a weapon system that was lighter, easier to carry, easier to produce in large quantities, and with a similar or better range and precision than javelins, the arm of choice of Neanderthal.
This shift from Middle to Upper Paleolithic is called the Upper Paleolithic Revolution. The development of more sophisticated tools, for the first time constructed out of more than one material (e.g. bone or antler) and sortable into different categories of functions, is often taken as proof for the presence of
"behavioral modernity" and fully developed language, assumed to be necessary for the teaching of the processes of manufacture to offspring.
The climate in North Africa becomes very favorable as well, as it worsen in Europe. The
Mousterian Pluvial was an extended wet and rainy period in the climate history of North Africa. It occurred during the Upper Paleolithic era, beginning around 50,000 years before the present (B.P), lasting 20,000 years, and ending around 30,000 B.P. The now-desiccated regions of northern Africa were well-watered, bearing lakes, swamps, and river systems that no longer exist. What is now the Sahara desert supported typical African wildlife of grassland and woodland environments: herbivores from gazelle to giraffe to ostrich, predators from lion to jackal, even hippopotamus and crocodile. These conditions would have logically resulted in a significant population increase in Northern Africa.
Modern humans is believed to have first migrated to Europe 40–45,000 years ago, taking this new technology with him. For about 150,000 years, H. Sapiens stayed in Africa and Middle East, never encroched into Neanderthal territory. A few millenia after they invent a radically new technology, giving them an edge over Neanderthal, they invade all of Europe.
Neanderthal went instinct around 30,000 years ago, perhaps hung out a bit longer in Spain. The Neanderthals continued to use Mousterian stone tool technology. He may locally have adopted some Aurignacian techniques but that is disputed. The species disappeared progressively from Europe as Sapiens was marching in, which is why the last spot where Neanderthaliens were found is Gibraltar: the far end of the continent. Neanderthal artefacts from Gorham's Cave in Gibraltar are believed to be less than 30,000 years ago, but a recent study has re-dated fossils at two Spanish sites as 45,000 years old, 10,000 years older than previously thought, and may cast doubt on recent dates at other sites.
Homo heidelbergensis also disappeared from Asia at about the same time... Most of the giant vertebrates and megafauna in Australia became extinct, around the time of the arrival of humans cirça 39,000 ybp.
This
map should give you an idea of population density in Europe during Aurignacian.
The climate during this period goes through a number of global temperature drops.
Growing ice sheets in North America and Europe displaced the standard climatic zones of the northern hemisphere southward. The temperate zones of Europe and North America acquired an
Arctic forest or tundra cover, and the rain bands typical of the temperate zones dropped to the latitudes of northern Africa.
Sapiens' population continues to increase during the colder
Gravettian culture (28–22 ka) characterized by a stone-tool industry with small pointed blades used for big-game hunting (bison, horse, reindeer and mammoth). People in the Gravettian period also used nets to hunt small game.
But now weather gets worse. Ice sheets were at their maximum extension between 26,500 and 19,000–20,000 years ago, marking the peak of the last glacial period (
Last Glacial Maximum). During this time, vast ice sheets covered much of North America, northern Europe and Asia. These ice sheets profoundly impacted Earth's climate, causing drought, desertification, and a dramatic drop in sea levels.
Sapiens takes refuge in Spain, southern Italy. Note that it is at this time when Sapiens moves to Spain in some numbers that the "hispanic" remnants of Neanderthal are believed to go instinct (circa 25,000 years ago). Sapiens himself went through a severe population bottleneck in Europe and Asia (not in Africa).
Climate amelioration begins to occur rapidly throughout Western Europe and the North European Plain ca. 16,000-15,000 years ago. The Late Glacial Maximum (ca. 13,000-10,000 years ago), or Tardiglacial ("Late Glacial"), is defined primarily by climates in the northern hemisphere warming substantially. It is at this time that human populations, previously forced into refuge areas as a result of Last Glacial Maximum climatic conditions, gradually begin to repopulate the northern hemisphere's Eurasian landmass and eventually populate North America via Beringia for the first time. The environmental landscape becomes increasing boreal except in the far north, where conditions remain arctic. Sites of human occupation reappear in northern France, Belgium, northwest Germany, and southern Britain between 15,500 to 14,000 years ago. Many of these sites are classified as
Solutrean or
Magdalenian. It's been called the Age of the Reindeer.
Climate may have played a marginal role, but Neanderthal disappeared much before the worse of the glaciation. A glacition which Homo sapiens survived in Europe and Asia... And bounced back from. At the End of Upper Paleolithic, world sapiens population is estimated at 5 million people. Neanderthal and Heidelbengensis are at 0.
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