Circannual Rhythms

Endogenous Annual Clocks in the Organization of Seasonal Processes
Softcover Nachdruck of the original 1. Auflage 1986
ISBN: 978-3-642-82872-0
Verlag: Springer

Buch, Englisch, Band 18, 156 Seiten, Format (B × H): 170 mm x 244 mm, Gewicht: 309 g

Reihe: Zoophysiology

In addition to the more or less static properties of the environ­ ment, plants and animals must cope with its temporal variations. Among the most conspicuous temporal changes to which organisms are exposed are periodic phenomena generated by the rotation of the earth about its axis, its revolution around the sun, and the more complex movements of the moon in relation to both sun and earth. The first two of these astronomical cycles are basic to the familiar daily and annual rhythms, respectively, in the environment. The third generates somewhat more complex cycles, such as those in moonlight and variations in tides. These environmental cycles have provided challenges and opportunities for organisms to adjust their physiology and behavior to them. Indeed, the predictability inherent to these periodic processes has enabled organisms to evolve innate endogenous rhythmic programs that match the environmental cycles and allow, in a variety of different ways, adjustment of biological activities to the cycles of environmental changes. The endogenous nature of rhythmicity was first clearly recognized in the 1930's in daily periodicities, the most widely distributed and best investigated class of biological rhythms of this type. In the 1950's, demonstrations of endogenous tidal and lunar rhythms, which occur in some littoral and marine organisms, ensued. Another decade passed before endogenous annual periodicities were first demonstrated unambiguously.

Zielgruppe

Research

Autoren/Hrsg.

Gwinner, Eberhard

Inhaltsverzeichnis

1. Introduction.- 1.1 The Phenomenon of Annual Rhythmicity.- 1.2 Ultimate and Proximate Factors in the Control of Annual Rhythms.- 1.3 Circannual Rhythms.- 1.4 Hierarchical Organization of Proximate Factors.- 1.5 Early Suggestions of Circannual Rhythms.- 1.6 Some Definitions and Delimitations.- 2. Evidence for Circannual Rhythms.- 2.1 Typical Cases.- 2.2 Atypical Cases.- 3. Properties of Free-Running Circannual Rhythms.- 3.1 Degree of Persistence and Range of Permissive Conditions.- 3.2 Range of Circannual Period Length and Transients.- 3.3 Dependence of Period on External Conditions.- 3.4 Innateness of Circannual Rhythms.- 3.5 Comparison with Circadian Rhythms.- 4. Synchronization of Circannual Rhythms.- 4.1 Zeitgebers.- 4.2 Ranges of Entrainment.- 4.3 Behavoir Within the Range of Entrainment.- 4.4 Comparison with Circadian Rhythms and Some Conclusions.- 5. Mechanisms of Circannual Organization.- 5.1 Interactions with the Circadian System.- 5.2 Interrelationship Among Different Circannual Functions. Or: One or Several Circannual Clocks?.- 5.3 Components of Specific Circannual Functions.- 5.4 Conclusions.- 6. Adaptive Significance of Circannual Rhythms.- 6.1 General Advantages of Circannual Rhythms.- 6.2 Specific Functions of Circannual Timing Mechanisms.- 6.3 Conclusions and Perspective.- Appendix. General Oscillator Model and Terminology.- References.- Systematic Index.