megafaunal extinctions: The extinction of large animal species in the
Paleolithic era, probably as a result of overhunting by humans; megafaunal
extinctions were particularly severe in lands newly colonized by humans
in the Australasian and American world zones, which is why those
regions had fewer large mammal species and therefore fewer potential
animal domesticates.
metabolism: One of the three fundamental features of living organisms; the
ability of all living organisms to take in energy from their surroundings; the
methods they use to do so (see also adaptation, reproduction).
microhistory: Study of the past on very small scales, often through the
biographies of individuals, or through study of particular events.
mitochondria: “Organelles” found within all eukaryotic cells, which
specialize in processing the energy of oxygen; they contain their own
independent DNA, which suggests, as Lynn Margulis has proposed, that
they were once independent organisms incorporated with eukaryotic cells
through symbiosis.
Modern era: One of the three great eras of human history, beginning within
the last two or three centuries; characterized by sharp increases in innovation
and productivity that rapidly transformed human societies throughout
the world.
Modern Revolution: A deliberately vague label for the revolutionary
transformations that have created the modern world; the “Modern
Revolution” ushered in the “Modern era” of human history.
monumental architecture: Large structures, such as pyramids or large
statues, that seem to appear wherever powerful leaders emerge; a feature of
all Agrarian civilizations.
Natu¿ ans: A culture of afÀ uent foragers whose remains are found in much
of the Fertile Crescent; from c. 14,000 BP, the Natu¿ ans lived in villages but
harvested wild grains and hunted gazelle; though they did not farm, their