The Spirit in Human Evolution - Waldorf Research Institute

food resource would provide the selection pressure and cited the Late Miocene climate
changes in East Africa. They suggest that uprightness gave early hominids an advantage
in an environment in which resources were more sparse, as they are on the savannah.
What their theory has going for it is a common sense analysis of the facts with none of
the major “ifs” that characterize many such early hominid models. What it still does
not explain, however, is the mechanism that brought about such radical morphological
change, nor why other primates, such as geladas or baboons, made the adaptation to a
savannah environment effectively without becoming upright walkers.
Maeve Leakey has suggested that the change to drier climate rewarded
bipedalism not by making them walk longer distances between stands of trees, as other
theories have it, but with the evolution of new plants, typical of grassland environments. 22
She argues that early hominids lived neither in dense forests nor on savannahs but in
environments with some trees, dense bushes and shrubs and some grass. She suggests
these plants provided many berries, fruits, insects and their larvae, birds’ eggs, all of
which primates are known to eat. Just as the gerenuk (a kind of antelope) during the
same period evolved its long neck and stands on its hind legs to reach higher branches,
uprightness would have been a distinct advantage to hominids when feeding off low
bushes.
As Robert Foley of Cambridge University has pointed out, 23 apes brachiate, they
swing beneath the branches when moving in trees. This upright position is supported
by an anatomy that has an innate tendency to truncal uprightness. The transition for a
species with essentially an ape anatomy to terrestrial locomotion would need less radical
modifications than for a creature descended from monkeys, which climb on all fours
along branches. The savannah baboons and geladas may not have become upright for
this reason when their ancestors left the forests and became terrestrial. With hominids
the anatomical reorganization would have been less extreme but nevertheless complex
enough.
Hominid ancestors were presumably closer to chimpanzees in their anatomy and
lifestyle, though the anatomical differences between knuckle-walking apes and bipedal
humans are profound. There is also a total absence of any evidence from the existing
fossil material for knuckle-walking among early hominids. As I have stressed above, the
earliest hominid fossils are more human than ape-like in their locomotive anatomy, and
the transition from brachiating ape to bipedal hominid remains unexplained.
Aquatic Ape Theory Resurfaces
There is one other theory that probably deserves further attention. This is Elaine
Morgan’s revival of an earlier theory called the Aquatic Ape, which she describes in
her book The Scars of Evolution (1994). The only scientist to take this theory seriously is
Desmond Morris who devoted part of a television documentary on human nature to
examine it. Taking up an idea first proposed by the zoologist Sir Alister Hardy back in
1960, Morgan lists a series of anomalous anatomical traits in humans which could be
interpreted as vestiges of an aquatic existence. These include our hairlessness, vestigial
earflaps, eyebrows, subcutaneous fat, the diving reflex in babies, the loss of oestrus cycle,
front to front sexual intercourse and the position and size of human genital organs. Like
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22
In interviews in Time Magazine, July 23, 2001, p59, and Scientific American, October 2001, p26.
23
Foley, R., 1995, Humans before Humanity.
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