Once characterised as the "tool-making" ape, human beings have shown an astounding propensity for technology. We unconsciously deal with technology every day, thinking we know its definition. We communicate instantly, pay debts electronically, and even post book reviews that millions can read. Jonathan Kingdon takes a deeper view of "technology". He considers it differently, suggesting "stones", "spears" and "fire" are more meaningful in our heritage than is electronics. It has, he contends, allowed our species to spread across the globe into every habitable niche. It also allows us to engage in a level of destructiveness unmatched by any other creature. The evolutionary roots of this behaviour are thoughtfully explained and rendered in this excellent study.
According to Kingdon, our use of technology helped drive our own evolution in ways Darwin never envisioned. The use of spears helped spur our exodus out of Africa in search of new food prey. Walking upright made the task increasingly easy. Shattered stones, shaped for precise use, became food processors - devices no leopard had at its disposal. Our prominent canine teeth, no longer needed, were reduced in size. Fire, that fearsome affair on savannah or woodland, was tamed to provide foods more easily and effectively digested. Our stomachs declined in size while the added proteins enhanced our brain. Fire also likely shaped our early social arrangements, bringing together the foundations of the kind of groups we're familiar with today.
Physical attributes responded to changes in habitat, diet and environment. The human face, drastically changed from its earlier primate visage. The human skull, once thickly ridged in our precursors, developed thinner bones, allowing changes in eye movement, extended our nose even as the capacity to detect smells declined. Our noses are more likely the result of needing to take in more air while moving or respiring in hot climates. Less chewing of food reduced the need for heavy jaw muscles, giving the brow more flexibility. Our expanding brains thus found room to grow. You can watch the process with every newborn child. Food - its finding, gathering and processing - is the pivot for much of our development.
Kingdon shows how the quest for food led to our emigration along traceable paths - riverine valleys, forested shorelines and wooded [but not forested] areas. The route of migration out of Africa followed a "Southern Route" along Arabia, India and into Southeast Asia. The recent find of Homo floresienses shows how diverse that movement could make us. We learned to follow animal tracks to water where prey resided, which also improved our bipedal capability. Extended range became increasingly the norm, but while it was once to our advantage, in today's world it foreshadows disaster.
The earliest indication what the future would bring was the Australia-Pacific region. It's only become known in recent years that the Island Continent was once home to many species of large fauna. Three-metre tall kangaroos, huge wombat-like browsers and killer birds once roamed Australia. Within a few millennia these all disappeared - shortly after our relatives crossed there from Asia. Similar extinctions occurred in the Western Hemisphere with similar timing. Over three-quarters of large mammals disappeared after humans entered North and South America. "Contrary to the sentimental image of a life in harmony with nature", Kingdon says, humans exploited fully whatever resources they encountered.
Old, genetically ingrained habits, he reminds us, die hard. We are still approaching our surroundings as if there was plenty to go around. If we deplete it, we retain the notion that there's somewhere else to go. And, having filled the planet, it's clear there's nowhere else to go. Kingdon discounts the optimists who think the "Green Revolution" is a solution to our rising population's food needs. He cites Japan, a nation struggling for self-sufficiency in rice by applying the best technology available, has likely "reached the limits of what rice can produce". Clearly, he urges, it is time to understand our past and seek more realistic strategies for the future. [stephen a. haines - Ottawa, Canada]