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.

Paleo-Indians expand across the American continent around 13,000 years ago, with their hunting potentially contributing to megafaunal extinctions alongside climate change. The traditional 'Clovis First' theory placed initial human arrival at this time via the Beringia land bridge. However, mounting evidence suggests humans reached North America much earlier, possibly 15,000-23,000 years ago.

Two primary migration routes are proposed: an inland ice-free corridor between the Laurentide and Cordilleran ice sheets, and a Pacific coastal route using watercraft. Coastal archaeological evidence would be submerged under post-glacial sea level rise of up to 100 meters.

The timing remains hotly debated, but scholars agree on Central Asian origins and widespread continental habitation during the late glacial period (16,000-13,000 years ago), when warming climates following the Last Glacial Maximum (26,500-19,000 years ago) enabled accelerated deglaciation and population expansion.

The roughly uniform techno-complex pattern known as Clovis appears in North and Central American sites from at least thirteen thousand five hundred years ago onward, but South American sites of equal antiquity do not share the same consistency and exhibit increasingly diverse cultural patterns.

The "Clovis-first" and Paleo-Indian hypothesis do not adequately explain complex lithic stage tools appearing in South America.

The current most widely accepted view among scientists is that the indigenous South Americans were part of the first wave of migrant hunters who came into the Americas from Asia, either by land, across the Bering Strait, or by coastal sea routes along the Pacific, or both.

The short chronology theory posits the first movement beyond Alaska into the New World occurring no earlier than fifteen thousand to seventeen thousand years ago, followed by successive waves of immigrants.

The long chronology theory proposes that the first group of people entered the hemisphere at a much earlier date, possibly twenty-one thousand to forty thousand years ago, with a much later mass secondary wave of immigrants.

The increased violence noticed historically in both Egypt and throughout the Near and Middle East, leading eventually to the Early Dynastic Period in both the First Dynasty of Egypt and Sumer, is associated with the period of the 5.9 kiloyear event.

James DeMeo and Steve Taylor suggest that this period is associated with the rise of patriarchy, institutionalized warfare, social stratification, abuse of children, the development of the human ego, separation from the body, the rise of anthropomorphic gods and the concept of linear historic time.

Narmer, thought to be the successor to the predynastic Serket, is considered by Most Egyptologists as the last king of the Protodynastic period as well as the so-called "Scorpion King(s)".

Some consider Narmer to be the founder of the First dynasty, and therefore the first pharaoh of all Egypt.

There is a growing consensus that Serket and Narmer are identical, but no identification with any early pharaoh can yet be definitively proven.

The hieroglyphic sign for a catfish (n'r) and that of a chisel (mr) represent Narmer's name phonetically.

Modern variants of his name include "Narmeru" or "Merunar,” but convention uses "Narmer.” Both sides of the large (around sixty-four centimeters/twenty-four inches tall), shield-shaped, ceremonial Narmer Palette, also known as the Great Hierakonpolis Palette or the Palette of Narmer, are decorated, carved in raised relief from a single piece of flat, soft green siltstone.

The famous palette, discovered in 1898 in Hierakonpolis, shows Narmer displaying the insignia of both Upper and Lower Egypt, giving rise to the theory that he unified the two kingdoms.

Menes is traditionally credited with this unification, and he is listed as being the first pharaoh in Manetho's list of kings, so this find has caused some controversy.

Some Egyptologists hold that Menes and Narmer are the same person; some hold that Menes is the same person as Hor-Aha and that he had inherited an already-unified Egypt from Narmer; others hold that Narmer began the process of unification but either did not succeed or succeeded only partially, leaving it to Menes to complete.

Arguments have been made that Narmer is Menes because of his appearance on several ostraca in conjunction with the gameboard hieroglyph, Mn, which appears to be a contemporary record to the otherwise mythical king.

There are, however, inconsistencies within every ostracon that mentions Menes, precluding any definitive proof to his identity.

Menes, an Egyptian pharaoh of the First dynasty, is to some authors the founder of this dynasty, to others he is the founder of the Second.

There is a substratum in Proto-Indo-Iranian which can be plausibly identified with the original language of the BMAC, as argued by Michael Witzel and Alexander Lubotsky.

Moreover, Lubotsky points out a larger number of words apparently borrowed from the same language, which are only attested in Indo-Aryan and therefore evidence of a substratum in Vedic Sanskrit.

Some BMAC words have now also been found in Tocharian.

Michael Witzel points out that the borrowed vocabulary includes words from agriculture, village and town life, flora and fauna, ritual and religion, so providing evidence for the acculturation of Indo-Iranian speakers into the world of urban civilization.

The Bactria-Margiana complex has attracted attention as a candidate for those looking for the material counterparts to the Indo-Iranians, a major linguistic branch that split off from the Proto-Indo-Europeans.

Sarianidi himself advocates identifying the complex as Indo-Iranian, describing it as the result of a migration from southeastern Iran.

Bactrian Margiana material has been found at Susa, Shahdad, and Tepe Yahya in Iran, but Lamberg-Karlovsky does not see this as evidence that the complex originated in southeastern Iran.

Western archaeologists are more inclined to see the culture as begun by farmers in the Near Eastern Neolithic tradition, but infiltrated by Indo-Iranian speakers from the Andronovo culture in its late phase, creating a hybrid.

In this perspective, Proto-Indo-Aryan developed within the composite culture before moving south into the Indian subcontinent.

The Proto-Iranians are traced to the Bactria-Margiana Archaeological Complex (BMAC), a Bronze Age culture of Central Asia.

The area between northern Afghanistan and the Aral Sea is hypothesized to have been the region where the Proto-Iranians first emerged, following the separation of Indo-Iranian tribes.

Kurgan cemeteries of the Vaksh and Bishkent type appear in the highlands above the Bactrian oases in Tajikistan, with pottery that mixes elements of the late BMAC and Andronovo-Tazabagyab traditions.

The walled BMAC centers decrease sharply in size about 1800 BCE.

Each oasis develops its own types of pottery and other objects.

Also pottery of the Andronovo-Tazabag'yab culture to the north appears widely in the Bactrian and Margian countryside.

Many BMAC strongholds continue to be occupied and Andronovo-Tazabagyab coarse incised pottery occurs within them (along with the previous BMAC pottery) as well as in pastoral camps outside the mudbrick walls.

The reliefs of the Punt expedition under Hatshepsut, depicting seagoing vessels carrying the expeditionary force returning from Punt, the location of which remains a matter of speculation, have given rise to the theory that, at the time, a navigable link existed between the Red Sea and the Nile.

Pharaoh Senusret III (1878 BCE–1839 BCE) of Egypt’s Twelfth Dynasty may have had a west-east river dug through the Wadi Tumilat, joining the Nile with the Red Sea (which at this time reaches north to the Bitter Lakes), allowing direct naval trade with Punt in its presumed East African locale, and, indirectly, linking the Red Sea and the Mediterranean.

However, numerous geological surveys conducted since the mid-1960s have found no physical evidence of any ancient man-made canal (as opposed to natural tributaries) existing in the region and extending from the Nile to the Red Sea.