In Passing
                                       
   HUMAN EVOLUTION
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   Books Discussed

  THE MAKING OF MANKIND by Richard E. Leakey
  
   (Michael Joseph, 1981, £9.95)

  MISSING LINKS by John Reader
  
   (Collins, 1981, £9.95)
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   Leakey Hypotheses

Jill Abery

   Jill Abery has an M.A. (Cantab.) in Natural Sciences and Zoology, and
   is one of the editorial team for S.I.S. Workshop.

   Leakey's BBC TV series and the inevitable accompanying book present a
   very similar story to his previous Origins, published in 1977 and
   written in collaboration with Roger Lewin of New Scientist. The Making
   of Mankind, however, does present more details of recent technological
   research and archaeological evidence of the "urban revolution". The
   jacket cover announces that "Richard Leakey and the BBC have combined
   their efforts to put the true picture of human evolution before a
   general audience for the first time." This is most misleading.
   Darwinian evolution has largely predetermined the manner in which all
   discoveries are interpreted and Leakey's objectivity is drastically
   confined within the narrow walls of a faith in evolution by natural
   selection which leads to some very illogical suppositions.

   The true picture of human evolution as presented by John Reader in
   Missing Links is a very large question mark. "The entire hominid
   fossil collection would barely cover a billiard table." The evidence
   of Richard Leakey's ten skulls from East Turkana "... is no more valid
   than any two thing Americans are today representative of the entire
   population of the United States". And, "It is particularly difficult
   to achieve absolute accuracy when dating fossil hominid levels." Yet,
   despite this, detailed evolutionary trees are worked out and new
   species named on the strength of a few teeth or skull fragments of
   doubtful date.

   Reader's book is an enthralling history of the discovery of hominid
   remains from 1857 when the first Neanderthal bones were found to add
   fuel to the fire of the early Darwinian debates, up to 1978 when a
   trail of three sets of footprints was uncovered at Laetoli in East
   Africa. The author succeeds admirably in presenting an objective
   account of each find, its circumstances and, above all, the
   preconceptions and bases of its finder. Writing about the case of the
   famous Piltdown forgery he says, "... science reveals a disturbing
   predisposition towards belief before investigation ..." Louis Leakey
   is shown to have a "... readiness to impose old ideas upon new
   evidence. Each discovery became a focus of controversy, some bitter,
   and the whole fossil hominid hunting scene is shown to be a race for
   honours and fame and often, as a corollary, funds for further
   expeditions." A century ago, with the proof of Darwinian evolution a
   beckoning goal, the peak honour was to find the missing link; now the
   emphasis has shifted to "the oldest man" and the current rivalry is
   between Richard Leakey at Lake Turkana and Don Johanson in the Afar
   Triangle.

   Reader interestingly observes that most anthropologists are
   gradualists, "... assuming human evolution was gradual and proceeded
   at a regular pace ...", but that some of their problems would be
   resolved if they accepted the idea of punctuated equilibrium. Leakey
   presents a set of associated facts which only require a condensed time
   scale to produce a catastrophically punctuated model. A small ape-like
   creature in Asia, called Ramapithecus, is considered as the earliest
   possibility for the man-ape ancestor. It had a gigantic relative in
   China and both "vanished" 8 million years ago. Then there is a
   4-million year fossil void during which there were major climatic
   changes, there was "an updoming of the earth's crust" in Africa, the
   Rift Valley formed, the major open-country animals appeared and,
   suddenly, there are hominids, already adapted to an upright posture
   which requires many anatomical changes. At Leakey's Lake Turkana site
   a sudden, drastic shrinking of the ancient lake, accompanied by a
   sudden change in climate, occurs at the same stratigraphical level as
   the apparent sudden arrival of a second type of stone tool culture,
   the penultimate Homo species as found in Java and China, and the
   presence of several giant herbivore species.

   The hominid record at Turkana and South Africa is bedevilled by the
   presence of two or three species at the same time and in nearby areas,
   difficult to correlate on slow evolutionary lines but not so difficult
   to explain in catastrophic terms. Misinterpretation of evidence is an
   ever present hazard. Neanderthal man was pictured for many years as a
   shambling, stooped half-wit until it was realized that the type
   specimen had been suffering from severe arthritis. A very telling
   piece of research was done by Owen Lovejoy on 1,300 skeletons from an
   old American burial site. Although the collection was all Homo
   sapiens, "... it included many unusual bones (distortions caused by
   injury or disease) that probably would have been assigned to a
   different species, or even a different genus, if they had been
   discovered as individual fossils".

   Not enough of this uncertainty comes through in Leakey's programme. It
   appears that he is a chip off the old block, as Reader says of his
   father Louis, "... the bold and inspiring story he told was as much
   the product of his intellectual and emotional preconceptions as it was
   a reflection of the evidence and the facts". His opening cartoon
   sequence indicates that he is a gradualist. From knuckle-walking ape
   to upright man in six easy moves was a misleading introduction. Leakey
   himself devotes time to showing that the earliest records of hominids
   indicate that a completely upright posture was the first really human
   trait, long before tool making or a large brain. Two exciting, recent
   pieces of evidence for this are the Laetoli footprints and Johanson's
   1974 find of an almost complete skeleton, "Lucy", which date back,
   conventionally, to 3½ million years. In both programme and book
   Johanson is given a fair hearing for his belief that his finds are of
   one, very variable species, Australopithecus afarensis, which is the
   oldest ancestor yet found for subsequent hominid lines. Leakey begs to
   differ, however, suggesting there are two species which diverged as
   long ago as 5 million years. This, of course, detracts from Johanson's
   claim to have found the "oldest" ancestor and underlines Leakey's
   belief in a slow evolutionary process. The large-brained type, Homo
   habilis, being well developed at 2 to 3 million years ago, an
   admission of "Lucy", a primitive, small-brained type, as an ancestor
   at 3½ million years ago needs to invoke rather rapid evolution.
   Significantly, the Afar Triangle is another region of "recent"
   volcanic upheaval and a large part of the fossil collection consists
   of "the first family", a mixture of remains of all ages indicating a
   group which died suddenly together.

   Proceeding out of a maze of fragile fossil fragments, whose story
   tells us, apparently, that posture came first, denture a close second,
   tools next, and only then the explosion of brain size, Leakey next
   guides us through these final stages of brain development towards Homo
   sapiens with the aid of the !Kung tribe and Natural Selection. The
   present-day !Kung of the Kalahari desert are Leakey's chosen example
   of the sort of hunter-gatherer life style our ancestors probably
   followed for at least 2 million years. His choice is motivated by the
   laudable desire to explode what he sees as the dangerous
   man-the-killer myth. Early man was not primarily a hunter, he says,
   but a scavenger and later a gatherer, with hunting a less important
   addition. The first societies were ones of sharing and co-operation;
   only so could such a physically ill-equipped animal survive. He does
   not see that this belief cannot logically be held at the same time as
   one of increasing brain size due to natural selection. In the first
   place he goes out of his way to show that this way of life is not
   "poor, nasty, brutish and short" so there can hardly be much selection
   pressure at all. In the second place, just how are the more
   intelligent members of a group going to leave more offspring if they
   are all cooperating?

   Homo erectus, the direct ancestor of Homo sapiens, evolved in Africa
   and remained there until 1½ million years ago, or so the story goes.
   It is interesting to note the main archaeological sites in this
   respect. European finds are usually accidental cave remains, while
   Java and Peking man were found after a concentrated search in a
   predetermined area. The oldest hominid remains are indeed all found in
   Africa but this could be due to a combination of a preconception that
   man did evolve there, and the existence of exceptional sites for
   excavation. However, the earliest European and Asian remains are all
   Homo erectus, so the story continues that early men moved out of
   Africa and spread to cover Europe and Asia, adapting to the more
   difficult life in colder, seasonal regions. One is tempted to ask why
   they should have left their African Eden at all. The known specimens
   exhibit some variation but "such biological variation arises when
   populations are geographically separated from each other for
   significant lengths of time". It is also a well-known tenet of
   evolutionary theory that such populations are then ideally placed to
   evolve into different species. How then did Homo erectus, with a brain
   three-quarters the size of modern man, after evolutionary stability
   for one million years, evolve simultaneously in Asia, Europe and
   Africa into one species, Homo sapiens?

   Early H. sapiens is represented by Neanderthal man, H. sapiens
   neanderthalensis, with a brain on average actually larger than that of
   modern man, but other more "primitive features such as eyebrow
   ridges". His habitat extended from western Europe to western Asia. In
   Europe the Petralona, Swanscombe and Steinheim skulls apparently
   exhibit characteristics in between typical H. erectus and H. sapiens
   neanderthalensis. In western Asia at Mount Carmel both typical
   Neanderthal and a form in between that and modern man are found.
   Neanderthal himself appears to vanish suddenly from the record. Did he
   undergo a rapid evolutionary burst into H. sapiens sapiens? Or was he
   replaced by a naturally selected stock from elsewhere? If so, was this
   Africa or the Near East? Leakey's solution is a compromise, a local
   sapiens population spreading and interbreeding with neanderthalensis.

   The life style of these early men is imaginatively pieced together
   with the aid of observation and some technology, but because so many
   of the remains have been found in caves a great deal is made of a
   supposed cave-man existence. As caves are probably last refuges and
   certainly better preservation areas than the open field, this picture
   could be hopelessly off centre, and possibly what we witness from
   caves is only the exceptional. The East African living areas by the
   shores of ancient lakes and rivers are much more credible locales as
   are the simple temporary huts by the sea shore at a site near Nice,
   thought to be nearly ½ million years old and contemporary with Peking
   man. Even this leaves a query however. Analysis of coprolites
   (fossilized faeces) shows by pollen contents that the camp was there
   during early summer. But how do faeces remain and become fossilized
   during the succeeding winter storms?

   By now Leakey is fast running out of time for he has to get modern man
   over the Bering Straits to populate the Americas and island-hopping
   over to Australasia before the ice-age ice melts and cuts off the
   routes with rising seas. Following the progress of man towards
   civilisation, he is a credit to the orthodoxy of the recent history of
   the world. Ice-ages come and go, seas rise and fall, Neanderthals even
   possibly evolve their stocky build due to pressures of life at the
   edge of the ice, men dwell permanently in caves, leaving artifacts and
   paintings in dim recesses, when not out following migrating reindeer
   herds over the tundra. It seems that the period between 40,000 and
   10,000 years ago is best represented by the "ice-age" evidence from
   the caves of the Pyrenees and southern France and, once again,
   imagination juggles a few isolated pieces of a vast jig-saw into a
   comprehensive picture of early H. sapiens as a combination of
   troglodyte and nomadic hunter. But what if ice-ages were sudden Earth
   tilts? Then the same jigsaw pieces can equally easily be made into a
   picture of survivors struggling for existence and manifesting, not
   incipient religious, artistic and social progress, but remnants of
   earlier skills. Catastrophe, even local, seems never to occur to
   Leakey. Remains of thousands of horses in one pile must have been the
   results of man's positive hunting and the remains of many animals in
   an area indicate that there were vast herds. Reindeer, horse, bison
   and ibex, a strange assemblage of ecological types by today's
   standards, dwell together. Interesting, though, in any context, are
   engravings of marine fish in caves in central France, nearly 200 miles
   from the sea; evidence from engravings and teeth that horses were
   domesticated and harnessed 30,000 years ago; that cattle were
   domesticated well before 13,000 years ago; and Alexander Marshack's
   interpretation of markings on certain Palaeolithic bone implements as
   symbolic representations of the seasons and even a record of the
   phases of the moon from 30,000 years ago.

   For the final phase of human cultural evolution we are taken out of
   Europe to the Fertile Crescent and Peru. It seems strange that each
   phase of human evolution manifests itself in a different area, usually
   appearing and ending suddenly, separated temporarily by "dark ages"
   and only really related in the minds of those who believe they must be
   related by gradual change over eons of time. Of all the problematical
   transitions recounted by Leakey so far, none is more inexplicable than
   the "agricultural revolution": "The speed of the transition was
   remarkable. For perhaps two million years human ancestors had
   practised nomadic hunting-and-gathering, a way of life that was
   characterised by stability rather than change in terms of technology
   and culture. Then the ancient way of life was virtually abandoned over
   a period of a few thousand years." Even more remarkable is the fact
   that "... it occurred in several different locations quite
   independently of each other". These different locations are as far
   apart as the Fertile Crescent, north-east China and Meso-America, yet
   Leakey does not even fall back on the idea of diffusion of culture. He
   is quite happy to invoke the "tremendous climatic change" at the end
   of the last ice-age as an explanation, but just how is a matter of
   much controversy. Leakey admits that: "When researchers disagree so
   strongly about the interpretation of available evidence it is usually
   a clear indication that there simply is not enough evidence
   available." This admirable quotation could really apply to the entire
   book and programme.

   The usual tale of wheat cultivation in the Fertile Crescent is
   enlivened by additional speculation about the procedure of the
   agricultural revolution in the New World. The facts are intriguing.
   The coastal strip of Peru, now an inhospitable desert, once supported
   ancient civilisations with skilful engineering in the form of complex
   irrigation canals and monumental architecture. Hundreds of ancient
   mounds are still unexplored and evidence shows that sophisticated
   populations lived there as long ago as 5,000 years. Early settlements
   here are supposed to have started in response to fishing activities,
   but in Meso-America there was a maize cultivation initiator. Wheat,
   maize, fish, vast climatic differences and racial types and a spatial
   separation of thousands of miles across vast oceans, yet suddenly and
   simultaneously, mankind is settled and building cities and monuments.
   What an insoluble problem when set in a non-catastrophic world with no
   long-distance navigators!

   Leakey stays in the Andes to introduce us to the moral in his story.
   Sculptures of butchered prisoners from Cerro Sechin lead him to
   hypothesize that aggression in mankind is not innate, but a product of
   the military organization that comes into being to defend property and
   community once a group is settled into an agricultural way of life.
   The sharing and mutual regard of the hunter-gatherer society is lost.
   However, it is difficult to see how just being aware of this can help
   us now. The first result of the agricultural way of life is a
   population explosion, which destroys forever the possibility of
   returning to a simple hunter-gatherer way of life. If, however, our
   aggressive, self-destructive behaviour is due to psychological
   race-trauma, then it would help if we looked long and hard at the
   jig-saw pieces that Leakey presents and opened our minds to the
   possibility that the picture of which they are the shattered,
   scattered remains is not a gentle evolutionary idyll but a series of
   catastrophic episodes.
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