Humans, apes, and Chinese fossils : new implications for human evolution : a seminar presented to the Department of Anatomy, University of Hong Kong

52 Pages·1985·2.838 MB·English

by  Charles E Oxnard

HUMANS, APES AND CHINESE FOSSILS
New Implications for Human Evolution
A seminar presented to the Department of Anatomy
University of Hong Kong
By
CHARLES E. OXNARD, B.Sc., M.B., Ch.B., Ph.D., D.Sc.
F.N.Y.A.Sc., F.A.A.A.Sc.
University Professor
Professor of Anatomy and Biology
Department of Anatomy and Cell Biology, School of Medicine, and
Department of Biological Sciences, College of Letters, Arts and
Sciences,
U niversity of Southern California
Overseas Associate, U niversity of Birmingham弓 England
Research Associate in Zoology, Field Museum of Natural History,
Chicago
Research Associate in Life Sciences, N atural History Museum,
Los Angeles
Honorary Professor of Anatomy, University of Hong Kong
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OCCASIONAL PAPERS' SERIES NO. 4
HONG KONG UNIVERSITY PRESS
@HongKong University Press 1985
First Edition, 1985
ISBN 962-209-073-7
Printed by Yee Tin Tong Printing Press Ltd.
South China Morning Post Building, Hong Kong
FOREWORD
The University of Hong Kong and its Department of Anatomy have paid me the
enormous compliment of continuing to invite me to present research lectures,
over the years.
These lectures have inc1uded, from time to time, many of the different lines
of research upon which 1 am embarked: biomechanics of bone form and
architecture, study of the deficiency of vitamin B in monkeys and apes,
12
mathematical, physical and engineering methods in functional anatomy,
relationships between morphological and molecular evolution in the primates,
and evolution of differences between the sexes.
Most of these lectures have been presented to the Department of Anatomy,
since my first visit there in 1969. But the Department of Orthopaedics, originally
under Professor Hutchison and later under Professor Arthur Yau, and the
Department of Statistics under Professor John Aitchison have also been kind
enough to host my talks. The University itself invited me to give the Huang-Chan
Memorial Lecture in 1980. And with these visits句 it has, many tim郎， conferred
upon me the title of、HonoraryProfessor of Anatomy'.
My more recent connections with the University of Hong Kong have lead to a
series of collaborations with Professor Wu Rukang of the Academia Sinica,
Beijing. These have involved studies of data from various fossils newly found in
China. As those investigations have progressed it has become abundantly clear
that the Chinese fossils have some powerful things to say, that challenge current
views of human evolution. My most recent investigations and the lectures 1 have
given have, thus, focussed around this theme. Starting with 1ectures on this new
work in October, 1982, Apri1, 1983 and January 1984, they have cu1minated in a
particu1ar 1ecture entitled Humans, Apes and Chinese Fossils that was given in
November, 1984司 under the aegis of the new Head of the Department of
Anatomy, Professor Brian Weatherhead. This 1ecture contained a summation of
all that had gone before, and included much new work resu1ting from this 1ast
year of collaboration with Professor Wu Rukang. It is, according1y, this 1ecture
that forms the basis for the present manuscript.
There is an especial appropriateness in my continuing links with the Depart
ment of Anatomy. You are all aware that 1 had known the previous Head of
Department, Emeritus Professor F. Peter Lisowski, very well indeed for a period
of over thirty years. That contact continues in
England. Our paths eventually diverged. 1 went on to the University of Chicago
and later to the University of Southern California. He moved to the University of
Lccds and reccntly came here. But in both Birmingham and Lceds we kept our
collcgial rc\ationship going over the years. 1 am especially pleased that it now
maturcs in Hong Kong.
1 am dc\ightcd to have been associated with this Dcpartment of Anatomy、 with
its faculty and staff, giving lectures and prosecuting collaborative researches first
with Profcssor Lisowski and now with Dr. Kenneth Chan. 1 am delighted also to
have hccn associated with the University of Hong Kong Press and its Puhlisher、
Mr. C. W. Toogood司 in the puhlication of the Huang-Chan Mcmorial Lecture:
Bcyond Bìol1lel!y: Holistù﹒ Views οl Bìological Strllcture and of my most recent
hook: 71zc Order q( Mall: alinealancestorofthispresentwork.I look forward to
thc puhlication of a further hook with the Press: Whence Man? Whence Woman? 1
am dc\ightcd to have hecn involved with this University over so many years. And
it is a final plcasure to discovcr‘ through Professor Brian Weatherhead, that this
rc\ationship will continue. Hopefully 1 may be a third anatomical c\ement in a
scrics of links bctwcen Anatomy in Hong Kong and Anatomy in China that surely
must develop during thc next ten years.
Charlcs E. Oxnard
19~5
ACKNOWLEDGE恥1ENTS
1 am most grateful to Profcssor Wu Rukang and his colleagues at the Institute for
Vcrtehratc Palcontology and Paleoanthropology司 Academia Sinica可 Beijing司 for
introducing me to the Chinesc fossils. Profcssor Bruce Gelvin, Department of
Anthropology司 California State University、 Northridge， has kindly provided me
with data for the living species. It is also a pleasure to thank Dr. Clifford Willcox,
Orthodontist、 Pasadena司 for allowing me access to human materials and records
in his care. And 1 am especially grateful to Dr. Susan S. Lieberman司 Department
of Anatomy and Cell Biology、 University of Southern California, who has carried
out many of the multivariate statistical analyses upon which this work depends.
In addition to help with analyses and data司 Dr. Lieberman and Professor
Gc\vin togcthcr with Professor G.H. Albrccht、 Department of Anatomy and Cell
Biology司 University of Southern California、 have provided most helpful discussion
of many of these problcms. Professor F. Peter Lisowski, formerly Head of
Anat()my、 University of Hong Kong、 and now in the Department of Anatomy、
University of Tasmania‘ Hobart, has also provided much helpful discussion and
given valuablc comments upon the manuscript.
Thanks are due to Mrs Eleanor Oxnard for editorial assistance.
The investigations are supported hy research grants from the University of
Southern California and by N .I.H. Biomedical Research Support Grant Funds.
CONTENTS
Foreword 111
Acknowledgements
lV
1 ANATOMICAL AND BIOMOLECULAR STUDIES
OF APES AND HUMANS
Morphometric studies of Apes and Humans 2
Human fossils: The conventional view 4
Morphometric challenges to the current story 8
2 SEXUAL DIMORPHISM AS A GENERAL
PHENOMENON 13
Sexual dimorphisms in the dimensions of teeth 14
Implications for Human evolution 31
References ci ted 42
Cover picture: comparative histograms see page 26
ANATOMICALAND STUDIES
BIO扎10LECULAR
OF APES AND HUMANS
Until 陀r'，e臼ce仰n叫 times there ha的s been little ar啥gumη1仰efnt αbout the e~ν101仙u叫ttionαFηyηy
r陀ef臼，αtionshi伊:ps of humans αnd gr陀e，ωGωt ape臼s (俗誼or吋iU臼0ω丸S， chiηmzpαnzees and orαaωng哺叫I的G仰n\).
For almost the entire span of time during which evolutionary studies of primates
have been carried out, it has been confidently asserted that humans are separate
from the great apes. This relationship is enshrined in taxonomy through the terms:
Hominidae and PO月idae (Figure 1). It is based almost entirely upon anatomical
studies at the organ and organismal level. The result is a view of the living
hominoids that sees the living apes as the end products of a radiation of pre-apes
with an early separation of a special lineage leading towards humans (early
divergence hypothesis).
It is the biomolecular revolution of the last two decad的， ， together with new
studies leading from it, that show that th臼 evolutionary split is not correct.
Groasuspicinalg MsI onhn erent in Groomuopli en gs Explicit in
仁lassical Morphology 8iomolecular Studies
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HYLOBATIDAE PONGIDAE HOMINIDAE 「一七「 戶可 f一-^----J
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HOMINOIDS HOMINOIDS
Fig 1. A tree representative of classical Fig 2. A tree representative of biomolec廿
morphological views of extant lar extant hominoid relationships
hominoid relationships. Asterisks indicate alternative possi
bilities.
可 HUMANS, APES AND CHINESE FOSSILS
The division is now known to be one between humans together with gorillas,
chimpanzees and bonobos (pygmy chimpanzee:吵 on the one hand， 的ld orang-utαns
alone, 01' possib砂 orang-u的ns together with gíbbons and siamangs, on the other
(Figure 2). This new picture has now been accepted by most anatomists even
though it is at variance to that presented by anatomy. The result sees the living
African apes and humans as one product of an evolutionary radiation (late
divergence hypothesis). The lineage leading towards orang-utans must have been
the early separation.
The new biomolecular data that support this view began with the studies of
individuals such as E. H. Y. Chu (e.g. Chu and Bender, 1961), V. Sarich and A. C.
Wilson, (e.g. Sarich and Wilson, 1967) and N. A. Barnicott (e.g. Barnicott, 1969).
But the concept of biomolecular evolution is actually very much older. Zucker
man (1933) relates how s叫1 information might tell us about the evolution of the
primates. Even earlier、 at the turn of the ce肌肉、 Friedenthal (1 900) and N uttall
(1 904) observed that the study of prin叫e blood groups indicated something
about their relationships. Earliest of all、 however， Darwin (1859) himself made it
quite clear that he had glimpsed the possibility of molecular evolution:
‘All living things have much in common句 in their chemical composition司 in
their cellular structure, . . . and in their liability to injurious influences\
What words of Darwin、s day could be more prophetic of the molecular、 bio­
chemical and immunological phrases of today?
MORPHOMETRIC STUDIES OF APES AND HUMANS
It is fascinating, then, that recent years have seen the development of new
anatomical studies of the living primates that support this biomolecular view. The
new studies examine anatomy through mathematical analyses of images and
measurements. The process, as broadly defined (Oxnard句 1978a)， is called
morphometrics.
The underlying basis of morphometrics is still observational anatomy. But it is
applied to much larger numbers of specimens than it is possib1e to observe or
dissect. The background studies involve dissection of many hundreds of primate
cadavers and observation of many thousands of bones. They also include、
however, morphometric analyses of many ten of thousands of measurements
taken upon them. The studies include almost every part of the primate body, and
almost all the different groups of the Order. These studies employ a battery of
techniques that include cluster finding procedures, stress and strain analyses,
image and pattern recognition, and Fourier transforms of patterns using lasers
(Oxnard, 1983a, 1984). The one we have used most often is muItivariate
statistical morphometrics.
Yet even only two decades ago morphometrics was a new and controversial
technique used in very few investigations (e.g. teeth: Ashton, Healy and Lipton,
1957; post-cranium: Oxnard, 1967; skull: Howells, 1973). Today it is accepted by
HUMANS‘ APES AND CHINESE FOSSILS 3
most biologists for studying the anatomy of living species (e.g. Reymer哎， Blackith
and Campbe11, 1 984; see also reviews by Fleagle、 1984; Stern, 1984; 恥100re司
1984).
Our earliest morphometric investigations tried mainly to understand the
functional anatomy of particular regions of the primate body, for example: the
structure and function of the shoulder (e.g. Ashton, Healy, Oxnard and Spence,
1965) and pelvis (e.g. Zuckerman, Ashton、 Flinn， Oxnard and Spence、 1973).In
these studies, we were interested in the relationship between anatomy and
function, between arm-swinging and the anatomy of the shoulder句 betwecn
bipedality and the anatomy of the pelvis.
More recently our morphometric studies werc aimed at investigating the
relationships of particular species among the primates (both living、 e.g. tarsiers
and aye-ayes, Oxnard、 1978b司 1981a, and fossil可 e.g. australopithecines、 Oxnard，
1975a、 b， 1980). In these particular studies it is the place of the anatomies of
particular species one against the other、 thatis examined.
Most recent1y of a11, however可 our investigations have become extensive
enough to study the primates as an Order, the Prosimii as an infra-order, the
Hominoidea as a superfamily, and so on (Oxnard, 1983a, 1984). For the
Hominoidea、 the studies particularly test the contradiction between classical
morphology and biomolecules句justoutlined.
Of these most recent studies, there are two sets that pertain to the evolution of
the living hominoids. One examines the morphometrics of their overa11 bodily
proportions (Oxnard, 1981 b). The other investigates the summated morpho
metrics of ma叮oftheir individual bodily regions (Oxnard、 1983b).
The late Professor A. H. Schu1tz a110wed the first set of investigations by
making available his data on the overa11 proportions of the primates. There are 23
dimensions representing every area of the body and they are available on 472
specimens representi月 34 primate genera (Schul位， 1936, summarized in Schul位，
1969). We have examined them using morphometrics (canonical variates
analysis). The results are clear. The hominoids are separated into humans and
African apes on the one hand可 and orang-utans and gibbons on the other
(Oxnard, 1981 b).
The summated morphometrics of individual bodily regions depends upon
separate morphometric investigations of several bodily regions defined through
suites of a dozen or so mea
HUMANS APES AND CHINESE FOSSILS
斗 ‘
Groupings Explicit in Morphometric Studies
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c Fig 3. A tree representative of morpho
C metri仁 extant hominoid relation
J ships. Asterisks indicate alternative
possibilities
HOMINOIDS
these radiations, and more especially, the details of their pattern and timing, be
perceived from equivalent morphometric studies of fossils?
This concordance between the biomolecular studies and the morphometric
investigations in living species suggests that morphometric studies of hominoid
fossils might supply a result that would be similar to what their biomolecules
might tell us if they could. (In fact, micro-biomolecular studies of fossils are
nowadays starting to be possible. The first such studies have been recently
reported in radio-immuno-assay of materials from extìnct speci肘， Lowensteìn,
19H5). However, before we look towards morphometric studies of the fossils
pertaining to the human evolutionary story句 we need to know what that story
currently is.
HUMAN FOSSILS: THE CONVENTIONAL VIEW
The genus Homo: The most recent human fossils of the last few tens of thousands
of years are little different from Homo sapiens of today and are clearly and
obviously of the same species.
It is the somewhat earlier group known as Homo sapiens neandertalensis that
presents an initial problem for human evolutìon. Although the first specimen was
the Gibraltar craníum found in 1848, the group takes its name from a skeleton
found in the Neander valley in Germany. Their skulls are different from ours,