The impressive performance of evolution as a design mechanism needs no belaboring. Physics, though, constitutes a larger reality that evolution can no more transcend than a cow can jump upward at escape velocity. Enzymes cannot act as Maxwellian demons, nor can birds turn off gravity. Physics limits life's designs no less rigidly than it constrains our own technology.

1.
J. D.
Isaacs
,
A. C.
Vine
,
H.
Bradner
,
G. E.
Bachus
,
Science
151
,
682
(
1966
).
2.
R. C. Pankhurst, Dimensional Analysis and Scale Factors, Chapman and Hall, London (1964).
3.
N. S. Land, A Compilation of Dimensionless Numbers, NASA, Washington, DC (1972).
4.
H. D.
Prange
,
K.
Schmidt‐Nielsen
,
J. Exp. Biol.
53
,
763
(
1970
).
5.
T. M.
Williams
,
J. Exp. Biol.
103
,
155
(
1983
).
6.
K. Schmidt‐Nielsen, in Scale Effects in Animal Locomotion, T. J. Pedley, ed., London, Academic Press (1977) p. 3.
7.
S. Vogel, Life in Moving Fluids, 2nd ed., Princeton U.P., Princeton, N.J. (1994).
8.
G. O.
Stride
,
Ann. Entomol. Soc. Am.
48
,
344
(
1955
).
9.
G. D. W.
Pommen
,
D. A.
Craig
,
Can. J. Zool.
73
,
373
(
1995
).
10.
R. M.
Alexander
,
Am. Sci.
72
,
348
(
1984
).
11.
R.
Kram
,
A.
Domingo
,
D. P.
Ferris
,
J. Exp. Biol.
200
,
821
(
1997
).
12.
N. C.
Heglund
,
C. R.
Taylor
,
J. Exp. Biol.
138
,
301
(
1988
).
13.
S. Vogel, Life's Devices: The Physical World of Animals and Plants, Princeton U.P., Princeton, N.J. (1988).
14.
D. A. Thompson, On Growth and Form, 2nd ed., Cambridge U.P., Cambridge, England (1942), p. 77.
15.
M. H. Zimmermann, Xylem Structure and the Ascent of Sap, Springer‐Verlag, Berlin (1983).
16.
S. Vogel, Vital Circuits: On Pumps, Pipes, and the Workings of Circulatory Systems, Oxford U.P., New York (1992).
17.
S. Vogel, Cats' Paws and Catapults: Mechanical Worlds of Nature and People, W. W. Norton, New York (1998).
18.
V. A.
Tucker
,
T. J.
Cade
,
A. E.
Tucker
,
J. Exp. Biol.
201
,
2061
(
1998
).
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