Thomas A. McMahon

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Copyright 1984 by Thomas A. McMahon
Published by Princeton University Press
41 William Steet Princeton, New Jersey

"A milestone. This book will follow in the biomechanical tradition of McNeill Alexander and S.A. Wainright." - Daniel Rubenstein, Princeton University

This is the first book-length treatment of mathematical models of muscle functions. Although physiologists, biophysicists, and bioengineers often mention these models, particularly the important Huxley models, Thomas A. McMahon is the first completely to explain them. He addresses the questions "What makes the force in muscle?" and "How is this force controlled?" with precision and clarity, explaining his assumptions and retaining the steps in derivations so that the reader clearly understands the capabilities and limitations of the models. Using this procedure, he discusses, among other topics, the workings of the muscle spindle organ, the enhancement of running speed by "tuned track," and the evolutionary implications of scale.

This book provides a framework for the many basic studies related to locomotion, which range from basic muscle mechanics and thermodynamics to coordinated motion. The author develops his comprehensive description of terrestrial animal locomotion by integrating evidence from biomechanical, physiological, morphological, and mechanical studies, without ignoring the complex ways in which these factors interact in the face of constraints imposed by size.

Copyright 1983 by Thomas A. McMahon and John Tyler Bonner
Published by Scientific American Books, Inc., a subsidiary of Scientific American, Inc. Distributed by W.H. Freeman and Company 41 Madison Ave., New York, New York 10010

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.

Cover image:
This beautifully detailed mosaic from a villa in Pompeii depicts the myriad forms of marine life.