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If elephants had legs proportioned like
those of mice, they would be unable to stand without breaking
them. Evolution produces organisms of varied sizes, and
it is through evolution that the problem of adapting to
that range of sizes is solved. The innumerable differences
between the large and the small were first touched upon
in the premier volume in the Scientific American Library,
Powers of Ten, and they are further delineated in
this book.
The authors, a biologist and an engineer,
consider the implications of size and shape for organisms,
beginning with a discussion of the role of size in natural
selection. This, however, is only half the story. On
Size and Life analyzes why size appears to impose specific
restrictions on shape (and shape on size), why there are
certain shapes that are physically impossible for large
organisms, and how natural selection and physical constraints
ally to eliminate nature's less efficient shapes.
Using microscope, camera, and mathematical
abstraction, the authors illuminate the beautiful regularities
of nature, bringing unity to the great diversity of shapes
found on earth. These discussions lead to a clearer understanding
of why there are flying squirrels but no flying horses,
why ants can lift 50 times their weight but humans struggle
to lift things that weigh no more than we do, and why the
smallest mammals and the smallest birds weigh about the
same.
Absorbing and accessible, this exquisitely
illustrated book imparts a fuller understanding of the intricacies
of size and proportion.
Thomas A. McMahon is Gordon McKay Professor
of Applied Mechanics at Harvard University. He is the author
of many articles on dimensional analysis in nature and on
animal mechanics. John Tyler Bonner is professor of biology
at Princeton University and a fellow of the National Academy
of Arts and Sciences. He is the author of several books,
including Cells and Societies, Size and Cycle,
and The Evolution of Culture in Animals.
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