Ultradian Rhythms from Molecules to Mind

A New Vision of Life

  • David Lloyd
  • Ernest L. Rossi

Table of contents

  1. Front Matter
    Pages i-xviii
  2. The Molecular-Genetic-Cellular Level

    1. D. Lloyd, D. B. Murray, R. R. Klevecz, J. Wolf, H. Kuriyama
      Pages 11-42
    2. D. A. Gilbert, K. D. Hammond
      Pages 105-128
    3. M. A. Aon, S. Cortassa, B. O’Rourke
      Pages 129-144
  3. Invertebrate Systems

    1. B. Fuentes-Pardo, C. Barriga-Montoya, M. Lara-Aparicio, S. López de Medrano
      Pages 147-161
    2. C. P. Kyriacou
      Pages 163-173
    3. M. K. Chandrashekaran, V. K. Sharma
      Pages 201-226
  4. The Neuroendocrineal and Developmental Level

  5. Ultradian and Circadian Rhythms in Human Experience

  6. Back Matter
    Pages 441-450

About this book


5. 1. 1 Biological Rhythms and Clocks From an evolutionary perspective, the adaptation of an organism’s behavior to its environment has depended on one of life’s fundamental traits: biological rhythm generation. In virtually all light-sensitive organisms from cyanobacteria to humans, biological clocks adapt cyclic physiology to geophysical time with time-keeping properties in the circadian (24 h), ultradian (24 h) domains (Edmunds, 1988; Lloyd, 1998; Lloyd et al. , 2001; Lloyd and Murray, 2006; Lloyd, 2007; Pittendrigh, 1993; Sweeney and Hastings, 1960) By definition, all rhythms exhibit regular periodicities since they constitute a mechanism of timing. Timing exerted by oscillatory mechanisms are found throughout the biological world and their periods span a wide range from milliseconds, as in the action potential of n- rons and the myocytes, to the slow evolutionary changes that require thousands of generations. In this context, to understand the synchronization of a population of coupled oscillators is an important problem for the dynamics of physiology in living systems (Aon et al. , 2007a, b; Kuramoto, 1984; Strogatz, 2003; Winfree, 1967). Circadian rhythms, the most intensively studied, are devoted to measuring daily 24 h cycles. A variety of physiological processes in a wide range of eukaryotic organisms display circadian rhythmicity which is characterized by the following major properties (Anderson et al. , 1985; Edmunds, 1988): (i) stable, autonomous (self-sustaining) oscillations having a free-running period under constant envir- mental conditions of ca.


Chronobiology attention bioinformatics biology cells eukaryotes life sciences neuroscience saccharomyces cerevisiae tissue

Editors and affiliations

  • David Lloyd
    • 1
  • Ernest L. Rossi
    • 2
  1. 1.Microbiology (BIOSI 1)Cardiff UniversityCardiffWales, UK
  2. 2.Los OsosUSA

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