ARTUR GLIKSON 
Mobility 
The hunters’ and collectors’ society must be a starting point 
for any study of the development of the man-environment 
relationship. Human communities, like other animals, keep 
moving from camp to camp to replenish supplies of food and 
water. In their natural ecological state, most regions can sustain 
human life for only part of the year. Man’s main energy 
*“‘investment”’ consists, as a result, of his own movement from 
one favourable ecological context to another—and as these 
optima change with the seasons, it can be said that man 
maintains his existence by a wise use of time rather than of land. 
In this context the landscape is formed by ecological systems in 
which man is no more than a temporary partner. To leave the 
land alone and to follow the sun is the rationale of man’s 
mobility. Its scale is almost unlimited by natural regions, 
bringing man into close contact with a wide range of conditions 
and situations. Inter-tribal contact is casual, and the general 
population density is estimated to be in some regions as low 
as 0*2 persons per square kilometre. Space is experienced 
essentially as exterior, a seasonally changing unbounded con- 
dition. Just as the flow of biotic energy moves continuously with 
the seasons through the ecological ‘“‘chains”’ of the landscape, 
human mobility likewise has no proper centre, though certain 
locations may be seasonally revisited. ‘The apparent exception 
to this order of mobility—early riparian settlement—proves the 
rule, for here we find an exceptional dynamic environmental 
condition: the regular movement of a whole eco-system, 
the river, combined with a favourable climate enabling man 
tostay in one place, while enjoying (as a beachcomber) 
an ever-replenished supply of food, materials and water 
dar as 
Sedentariness 
Sedentariness is perhaps the most astonishing biotechnical 
“invention”? and the most successful revolution ever carried 
through in man’s relation to his environment. The conditions 
for sedentariness are the acquisition of biological knowledge and 
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