The Andamans are members of a racial group called , which appear to be remnant populations of the original migration from Africa. They all survived in marginal environments where they subsisted as hunter-gatherers, while later agricultural immigrants dominated arable lands. About 50 kya, a few thousand years before the migration to Australia happened, the sea level was lower and the islands of , , and formed a contiguous peninsula today called . , Australia, and were also connected and formed a continent today called . Deep water lay between those two “lost continents,” and biologists drew lines between them that noted the distribution of animals and plants that did not cross open water. is farthest north, followed by , and is farthest south. Those lines mark the limits of migrations from Sundaland toward Sahul, which followed sea level changes. About 48-46 kya, behaviorally modern humans crossed the water in boats to Sahul, and the peoples of New Guinea, Australia, and Tasmania largely lived in isolation until Europeans arrived. Those peoples have remnants in their DNA, which probably means that they interbred with them while driving them to extinction on Sundaland and Southeast Asia, before some migrated to Sahul. Aboriginal Australian isolation was almost certainly maintained in the way that Andaman Islanders did it: by killing strange peoples who came ashore. However, in 2012, a paper was published regarding evidence of contact about four kya with people probably from India, when the , , and some Indian DNA admixture were introduced into Australia, which seems related to a colonization of northern Australia by an immigrant population. More of those kinds of migrations of human DNA, technology, and domesticated species have yet to be discovered, and some may even be significant.
Economics is the study of humanity’s material well-being, but humans have rarely thought past their immediate economic self-interest, even when the long-term prospects were obviously suicidal, such as today’s global energy paradigm. Because environmental issues affect humanity’s material well-being, they are economic in nature. As can be seen so far in this essay, there was little awareness or seeming caring in early civilizations whether they were destroying the very foundations of their civilizations. Even if they did not care how much other life forms suffered, they did not seem to realize that it also meant that those oppressed and exterminated organisms and wrecked environments would not provide much benefit to humanity in the future, especially energy, whether it was food or wood.
Historicity of Homer - Wikipedia
Neanderthals seem to have become permanently separated from their kin when the ice sheets grew about 300 kya, and between 250 kya and 200 kya two glacial events happened, which roughly coincided with the final exit of and the appearance of either or that . The previous interglacial period began 130 kya and ended 114 kya, and it appears that left Africa for the first time about then; evidence is , and they may have traveled much farther. When ice sheets advanced, Neanderthals retreated southward, and one controversial area is the overlap of Neanderthals and in Israel during that interglacial period. Did Neanderthals wipe out those first migrants from Africa? Did they interbreed?