Writting2 | Reading homework help

leguminous grains. None of the New World’s complex

societies—Incas, Mayas, or Aztecs—acquired the first two

traits, but their cropping was often more productive than

harvests in Europe and Asia.

Many cattle breeds provided draft power, both for

field work and for transportation. They also supplied

milk, but they were too valuable to be slaughtered for

meat unless they got very old. Horses were used exten-

sively in war from antiquity—but they became superior

draft animals only with the adoption of an eYcient harness

and iron horseshoes, and their widespread use in tradi-

tional agriculture came only when changes in cropping

patterns provided enough concentrate feed.

Virtually all fuel in preindustrial societies came from

wood, charcoal, and straw. For household cooking and

heating, these fuels were burned ineYciently in a variety

of fireplaces; enclosed stoves with chimneys are a surpris-

ingly late innovation. Because of its high energy density,

charcoal was the preferred fuel for smelting and pro-

cessing metals, mainly copper, iron, and steel, and for fir-

ing bricks.

Our ancestors spent more than nine-tenths of their exis-

tence as hunters and gatherers in activities that required

many physical and mental adaptations and were also indis-

pensable for the emergence of social complexity. But only

in some coastal communities, tapping rich seasonal migra-

tions of ocean fish and mammals, could foraging support

high population densities and lead to a sedentary exis-

tence. On grasslands and in forests population densities of

roaming foragers were hardly higher than those of their

primate ancestors.

As their numbers rose, most foragers had to turn to

an increasingly sedentary way of cropping. These agricul-

tural practices began with shifting cultivation. In this

least energy-intensive mode of crop production the culti-

vation of several crops of tubers, grains, or fruits on a

patch of land cleared of natural vegetation (usually by fire)

alternated with often long periods of fallow.

A further rise in population densities brought a vari-

ety of traditional agricultures. Throughout the Old

World human groups shared domestication of animals, re-

liance on plowing, and the cultivation of staple cereal and



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Most preindustrial labor was done by muscular exer-

tions of people and animals. More powerful sources of

kinetic energy—waterwheels and windmills—were in-

vented only after millennia of settled societies, and in most

such societies they made only marginal contributions. The

capacities of these mechanical prime movers, used for

many food processing and manufacturing tasks and also in

raising water, grew only slowly.

Improvements in the typical performance of sailships

were also very slow. Fundamental breakthrough came only

at the beginning of the early modern era. At that time the

combination of more maneuverable vessels with more ac-

curate guns (made possible by advances in the smelting

of copper and iron and by the invention of gunpowder)

produced an energy converter of unprecedented speed,

range, and destructive power that helped to usher a new

era of world history.

Hunters and Gatherers
Only an uninformed view would not perceive tens of

thousands of years of hominid foraging as a prolonged

prelude to a truly sapient existence in increasingly complex

civilizations. To continue the musical analogy, it was very

much like acquiring a large ensemble of specialized instru-

ments, fine-tuning them, and getting them ready to play

ever more intricate scores. Development of all of the key

characteristics distinguishing humans from other pri-

mates—bipedality, manual dexterity, elaborate tool mak-

ing, intergenerational transfer of technical skills, and

higher encephalization—was fostered by our evolution

from simple foragers to sophisticated hunters and incipi-

ent plant cultivators.

The earliest foragers were almost certainly opportu-

nistic scavengers, taking advantage of partially eaten herbi-

vore carcasses left behind by large predators—or at least

breaking the bones to extract the nutritious marrow. They

were obviously omnivorous, collecting and killing scores

of diVerent edibles, but a small number of foods was usu-

ally dominant. Large roots—easily found by associated

leaves or stalks and dug out quickly with the help of

pointed sticks—provided the highest (up to fortyfold) net

energy returns in gathering. But unlike grains, which

were also easy to collect and had higher energy content,

they were low in protein. High returns in collecting large

seeds and nuts were reduced by often considerable energy

expenditures in their processing.

Typical gathering of a wide variety of plant foods re-

turned at least ten to fifteen times the invested energy, ra-

tios similar to killing large mammals—while hunting

smaller animals yielded much smaller energy returns. For-

aging was especially unrewarding in tropical forests where

edible fruits and seeds are a very small share of total plant

mass and are mostly inaccessible in high canopies. And

because most tropical mammalian herbivores are arbo-

real, their hunting also yielded low energy returns. This

explains why there is no unambiguous ethnographic ac-

counts of tropical foragers who would not engage in some

plant cultivation.

In contrast, grasslands provided excellent foraging

environment. Grass seeds and starchy roots were easy to

collect, and there were many large herbivores. Cooperative

hunting of large ungulates—much more rewarding than

solitary pursuits—clearly made lasting contributions to



Comparison of the oldest Oldowan tools with larger
Acheulean hand axes used to butcher animals.

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two thousand-fold net energy return, perhaps the highest

documented foraging gain. Much lower, but still very

comfortable, ratios were obtained by killing seals or catch-

ing migrating salmon. Seasonal abundance of such foods

could be also easily preserved by drying or smoking and

stored for later use. Large-scale food storage helped to sta-

bilize populations at higher densities: maritime foragers

could cease roaming and could live in fairly large, perma-

nent settlements with social stratification, elaborate ritu-

als, and long-distance trade.

Except for some maritime cultures, foraging societies

could not attain population densities needed for func-

tional and social diversification. The least hospitable envi-

ronments (tundras, boreal forests) supported population

densities of just 1 person/km2, while the most suitable

habitats (tropical and temperate grasslands) could carry

from ten to a hundred times more people. Because of

diVerences in phytomass storage, accessibility and edibility

of plant parts, and sizes and habits of hunted animals these

large density variations had no simple correlations with

total photosynthesis or biodiversity of habitats.

human socialization. Many large mammals could be killed

by skilfully driving them into confined runs and capturing

them in pens or natural traps, or by stampeding them

over cliVs.

But simple energy ratios favoring the killing of bison

over the snaring of hares does not capture the desired

quality of hunted food. Foraging diets were often low in

lipids, and inland hunters could satisfy the apparently uni-

versal craving to eat filling fat, rather than just lean meat,

only by killing larger fatty mammals. This is why the Afri-

can hunters, exploiting the unique human capacity for

long-distance running, were willing to chase big ante-

lopes to exhaustion; this is why their counterparts in bo-

real Europe were willing to face huge woolly mammoth

with their simple spears; or why North American Indians

invested so much eVort into driving bisons across preci-

pices: energy return on their labor investment was eating

food uncommonly filling with lipids.

Maritime hunters could get similar rewards with usu-

ally much less exertion. Killing of migrating baleen whales

by the Northwestern Alaskan Inuit provided more than a



boreal or subarctic

foraging environments




































Twana Micmac

Approximate contributions of gathering, hunting,
and fishing to typical diets of some foraging societies

surviving into the twentieth century.

Population density (people/km2)
















10 3

10 2

10 1

10 -3 10 -2 10 -1 10 0

Relationship between population density and annual travel in
foraging societies: Maritime cultures could be least mobile.

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Although some foraging societies had to spend just a

few hours a day to enjoy abundant food supply, other had

to cope with recurrent hardships intensified by seasonal

food shortages leading to high infant mortalities (and to

infanticide) and to often devastating famines. The idea of

foraging existence as the original aZuent society is clearly

an impermissible generalization.

Overall energy returns of crop cultivation were com-

monly lower than those for many kinds of foraging, and

that is why hunters and gatherers coexisted with settled

agricultural societies for hundreds, and sometimes even

for thousands, of years. But even extensive cultivation

could support higher population densities and assure a

more reliable food supply than that enjoyed by most

foraging societies. The fastest transition to permanent

cropping happened on fertile floodplains, but elsewhere

agriculture began, and continued for often very long

periods, as shifting cultivation.

This practice extended from rainy tropics to the sub-

arctic forests, and it encompassed a wide variety of species



Burning of forest phytomass, the first
step in creating temporary fields.

modern farming

traditional farming

shifting farming









2 )

10 3

10 2

10 1

10 0


10 -2

Shifting cultivation could support population densities two
orders of magnitude higher than foraging—but an order of

magnitude lower than traditional farming.

Shifting Cultivation
Adoption of plant cultivation, and in most cultures also of

associated domestication of animals, was a multifocal and

gradual process stimulated by population growth beyond

the densities supportable by foraging and by environmen-

tal changes (such as a drier climate or elimination of pre-

viously abundant prey) reducing food supply that hunters

and gatherers could get by foraging. Diminishing energy

returns in foraging favored more regular reliance on incip-

ient cultivation begun with the deliberate planting of tu-

bers or scattering of seeds that was practiced by many

gatherers.Domestication of wild grains and cattle oVered

a supply of high-quality nutrients.

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ping. Net energy returns for grains, be they tropical

(dryland Asian rices), subtropical (African millets), or tem-

perate (European rye) ranged mostly between ten and fif-

teen. Less labor was needed for corn (its energy returns

were commonly more than twentyfold) and for tropical

tubers, legumes, and bananas (the best energy returns

ranged between forty and seventy). Ancient Mesoamerica,

with staples of corn, beans, and squash, achieved some of

the highest food production eYciencies, but even less

eYcient shifting cultivation could support population

densities ten times higher than those of prosperous hunt-

ers and gatherers. Minima were about 0.2 people per

hectare in Eastern North America (corn gardening), max-

ima surpassed 0.6 people per hectare in Southeast Asia

(upland rice and roots). High energy returns sustained

shifting cultivation in parts of Asia, Africa, and Latin

America into the twentieth century. Higher population

densities and shorter regeneration cycles have been the

main reasons for its recent decline.

Traditional Agricultures
DiVerences in climate, soils, crops and in specific farming

practices created a great variety of traditional agricul-

tures—but physical imperatives of field cultivation dic-

tated a recurrent pattern of labor. Throughout the Old

World the sequence begun with plowing and harrowing

which prepared loosened, weed-free, well-aerated, and

leveled soil ready for sowing (mostly by hand). Plow de-

signs progressed from the simplest symmetrical scratch

plows, which created merely a shallow furrow for seeds,

to asymmetrical moldboard plows—first just straight

pieces of wood, later with curved metal plowshares—

which turned soil over, buried the cut weeds, and elimi-

nated the need for crossplowing. Harvesting was done,

slowly, by sickles, later by more eYcient scythes (the first

successful mechanical reapers were introduced only after


and local peculiarities. But everywhere it alternated be-

tween short periods of cropping (commonly just one sea-

son, rarely more than three years) and long spans of fallow

(sometimes up to twenty-five to thirty years, more com-

monly at least a decade). The cropping cycle began with

often only partial removal of natural phytomass. In forests

and shrublands this was done by a combination of felling,

slashing, and burning; in grasslands just by setting fires.

Nearly all nitrogen was lost in combustion, but mineral

nutrients helped to produce at least one or two fairly

good crops.

Cultivated species included cereal and leguminous

grains, tubers (sweet potatoes, cassava, yams), vegetables,

fruits, fibers, and medicinal plants. Few staples provided

most of the food nutrients, but the total number of

planted species was rarely less than a dozen, and in warmer

environments it often surpassed two scores. Cultivation

was done commonly in jumbled, gardenlike arrange-

ments, with high degrees of interplanting and intercrop-



Roots have been dominant staples in tropical shifting cultivation.

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