Bipedal Locomotion

Author(s): Jon Marks

Reviewed work(s):
Source: Science, New Series, Vol. 236, No. 4807 (Jun. 12, 1987), p. 1412
Published by: American Association for the Advancement of Science
Stable URL: http://www.jstor.org/stable/1699690 .
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 A defense must be better than 99% effective an arboreal lineage marked by flexibility of 4. A. Zihlman and L. Brunker, Yearb. Phys.Anthropol.
22, 132 (1979).
(99% still could allow 100 Soviet nuclear the hip and particularly of the shoulder, 5. J. Napier, Sci. Am. 216, 56 (April 1967); J. T.
bombs to destroy 100 American cities), stride with the opposing forelimb forward. Robinson, Early Hominid Posture and Locomotion
(Univ. of Chicago Press, Chicago, 1972); H. Mc-
whereas an offense is catastrophicallydevas- Balance is achieved in the absence of a tail Henry and L.Temerin, Yearb. Phys. Anthropol. 22,
tating if it is only a few percent effective. through rotations of the thorax and pelvis in 105 (1979); S. Kondo, Ed., Primate Morphaphysio-
logy: LocomotorAnalyses and Human Bipedalism
8) Can we expect the Soviets to bargain opposite directions (1). (Univ. of Tokyo Press, Tokyo, 1985).
away their offensive missiles while we retain As is usually the case in parallel and 6. P. Hershkovitz, Living New WorldMonkeys,vol. 1,
and continue to add first-strikemissiles and convergent evolution, the similarities Platyrrhini (Univ. of Chicago Press, Chicago,
1977), p. 118.
build a shield from behind which to launch among the three groups are superficial, 7. J. Charteriset al.,J. Anat. 128, 803 (1979).
them? which makes it unlikely that the evolution of
9) The SDI systems now being sought, if hominid locomotion could be modeled ef-
even partially successful, would be of great- fectively by recourse to other groups.
est threat to existing and future satellites and Anthropologists have realized that the Immigrant Entrepreneurs
thus to the SDI's own systems in space. SDI uniquely derived locomotor features of the
sows the seeds of its own destruction. different taxa serve as effective contrasts to The article on the economic impact of
10) Rather than slow or stop the arms one another. Hooton, in both editions of Up immigration by George J. Borjas and Marta
race, SDI will create a whole new defensive from the Ape (2), figured the skeleton of a Tienda (6 Feb., p. 645) omits mention of
arms race layered upon a renewed and accel- kangaroo in this regard. Howells, in Man- one very important factor-entrepreneur-
erated offensive arms race. Technology de- kind in the Making (3), also gave a cursory ship. The authors discuss the impact of
velopment never ceases; it is open-ended. contrast among the bipedal groups. A more immigration as a matter of competition for
Continuous development of sophisticated recent review of hominid locomotion in- jobs. This conventional approach does not
defensive technology will be followed by cludes a photograph of one of the authors acknowledge that immigrants are creating
even more sophisticated offensive technolo- actually locomoting alongside a kangaroo jobs for themselves and others through en-
gy, followed by ... ad nauseum, ad holo- (4). trepreneurialpursuits. Such an omission has
caust. Further, hominid bipedalism, although it serious policy implications. To the extent
SDI could end up costing us far more is the biological hallmark of our clade, is that the problem is viewed as a static jobs
than merely our money and resources. nevertheless a learned behavior, and there is allocation issue rather than a dynamic jobs
JOEL SELBIN no evidence that this is the case in other taxa. creation issue, some credibility is lent to a
Department of Chemistry, Major studies therefore assume that the familiar congressional reaction to immigra-
Louisiana State University, distinctness of human locomotion does not tion: They are stealing jobs from our people.
Baton Rouge, LA 70803-1804 require further belaboring (5). Indeed, it Any such implication is unjustified and un-
does appear to be the case that, as Farlow fortunate because, clearly, it is not the posi-
puts it, "the shift from quadrupedalism to tion of the authors nor is it one implied by
bipedalism is fundamentally different from their results.
Bipedal Locomotion one vertebrate group to the next," mechani- Evidence from my own studies (1) of
cally, historically, and developmentally. The minority and ethnic entrepreneurship com-
James 0. Farlow (Letters, 17 Apr., p. emergence of these derived locomotor fea- plements that in the article. Statistical analy-
243) discusses the parallel evolution of bi- tures across taxa is no more amenable to a sis of microdata from the 1980 Public Use
pedal locomotion and chastises anthropolo- singular explanation than is the parallel loss Sample shows that the odds of someone
gists for not looking to other taxa as models of an os baculumin spider monkeys, tarsiers, being self-employed increase significantly if
for the evolution of human locomotion. and humans (6); reduction of the tail in the individual has immigrant characteristics.
Students of paleoanthropology, however, pottos, hominoids, and Manx cats; or the It is high time that labor economists take
have good reason not to be preoccupied loss of teeth in birds, baleen whales, and account of entrepreneurship in their meth-
with modeling the locomotion of humans hockey players. odology and also recognize that immigrant
after that of theropod dinosaurs or kanga- It is possible, finally, that the problem groups have revitalized many previously
roos, since the three forms of bipedal loco- perceived by Farlow is the result of a termi- run-down urban areas, for instance, the Cu-
motion share few features aside from a nological laxity: while "bipedalism" is not bans in Miami and the Koreans in Los
common adjective. uniquely human, "walking" (as biomechani- Angeles.
The development of a two-legged gait in cally defined) is (7); and that is the focus of PETER BEARSE
dinosaurs was channeled by the constraints the anthropological investigations reported DevelopmentStrategiesCorporation,
of a reptilian vertebral colunm flexible me- by Lewin (Research News, 27 Feb., p. 969). Post OfficeBox 603,
diolaterally, combined with relatively rigid JON MARKS Trenton,NJ 08611
pelvic and shoulder girdles. A bipedal stride Department of Anthropology,
would likely involve a forward movement of Yale University,
REFERENCES
both limbs on the striding side simulta- New Haven, CT 06520
1. P. Bearse and P. Johnson, A ComparativeAnalysis of
neously, or keeping the upper body immo- Minority and Ethnic Entrepreneurshipin the U.S. as of
bile, to produce a lurching or waddling REFERENCES AND NOTES 1980 (Office of Research, Minority Business Devel-
1. J. Maynard Smith, The TheoryofEvolution (Penguin, opment Agency, Department of Commerce, Wash-
stride. Nonprimate mammals, with back- ington, DC, 1986).
Baltimore, ed. 2, 1966), p. 266; B. Newman, Biol.J.
bones more flexible dorsoventrally, move as Linn. Soc. 2, 119 (1970).
bipeds (exemplified by the kangaroo) with 2. E. A. Hooton, Up from the Ape (Macmillan, New
York, ed. 1, 1931; ibid., ed. 2, 1946). Erratum: In the letter "Tanker'dumping' regulations"
both anterior limbs moving together and 3. W. W. Howells, Mankind in the Making (Double- by T. S. Wyman (5 June, p. 1160), the years of amenda-
both posterior limbs moving together-a day, New York, 1967) [see also B. Campbell, Hu- tions to the International Convention for the Prevention
man Evolution (Aldine, New York, ed. 3, 1985) and of Pollution from Ships, 1973, mentioned in the second
hop. Both groups maintain balance with the J. Buettner-Janusch, Origins of Man (Wiley, New paragraph,were incorrect. The amendations were made
aid of a large tail. Humans, generated from York, 1966), p. 310]. in 1978, 1984, and 1985 (not 1987).

1412 SCIENCE, VOL. 236