Circannual Clocks: Annual Biological Rhythms documents the Proceedings of a Satellite Symposium of the 140th Meeting of the American Association for the Advancement of Science held in San Francisco, California, February 25, 1974. The purpose of the symposium was to summarize the present state of knowledge on endogenous annual rhythms (circannual clocks), and to point out their biological significance and importance. The presentations included studies on the following: the circannual rhythms of an arthropod, the cave crayfish, Orconectes pellucidus inermis, and a cnidarian, Campanularia flexuosa; the occurrence, manifestation, and importance of circannual rhythms in birds with different migratory habits; and the importance of circannual rhythms in hibernating mammals. Also covered are the relationships between circannual rhythms and endogenous lunar and tidal rhythms; circannual rhythm of reproduction in male European starlings; the adaptational value of internal annual clocks in birds; the expression and suppression of the circannual antler growth cycle in deer; and circannual rhythms in man.

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.

Leading authors review the state-of-the-art in their field of investigation, and provide their views and perspectives for future research Chapters are extensively referenced to provide readers with a comprehensive list of resources on the topics covered All chapters include comprehensive background information and are written in a clear form that is also accessible to the non-specialist Leading authors review the state-of-the-art in their field of investigation, and provide their views and perspectives for future research Chapters are extensively referenced to provide readers with a comprehensive list of resources on the topics covered All chapters include comprehensive background information and are written in a clear form that is also accessible to the non-specialist

The Handbook of Behavioral Neurobiology series deals with the aspects of neurosciences that have the most direct and immediate bearing on behavior. It presents the most current research available in the specific areas of sensory modalities. This volume explores circadian rhythms.

This book explores how daily and seasonal rhythmicity is generated, how these rhythms are synchronised by our environment, and how they regulate the neuroendocrine systems that impact our physiology and behaviour. The constraints of surviving in a seasonal environment have shaped human evolution and migration, have shaped our societies and cultures, and continue to influence our everyday lives, health and wellbeing. Identifying the mechanisms whereby seasonal rhythmicity is generated and regulates the brain and body is not only important for understanding the natural world and relevant to animal production, it also offers many insights into the human condition. Each chapter is written by an international expert in the field of chronobiology. A historical perspective on how research into photoperiodism and rhythmicity progressed is initially provided, but the main focus of this book is on the remarkable studies in the last few decades that have unravelled the molecular and cellular machinery underpinning circadian and circannual timing. Topics covered include the role of melatonin in communicating seasonal information to the brain and pituitary gland, the neuroanatomical pathways in mammals, birds and fish by which changes in photoperiod reach the hypothalamus, the role of glial cells (tanycytes) and thyroid hormone in seasonal rhythmicity, neuroplasticity across seasons, effects of changing day length on mood, regulation of “clock“ gene expression, and the role of the suprachiasmatic nucleus. This book will appeal to all students and researchers who wish to learn about current and past research on daily and seasonal rhythmicity. This is the tenth volume in the International Neuroendocrine Federation (INF) Masterclass in Neuroendocrinology series (Volumes 1-7 published by Wiley) that aims to illustrate highest standards and encourage the use of the latest technologies in basic and clinical research and hopes to provide inspiration for further exploration into the exciting field of neuroendocrinology.

Environmental conditions change considerably in the course of 24 h with respect to abiotic factors and intra- and interspecific interactions. These changes result in limited time windows of opportunity for animal activities and, hence, the question of when to do what is subject to fitness maximisation. This volume gives a current overview of theoretical considerations and empirical findings of activity patterns in small mammals, a group in which the energetic and ecological constraints are particularly severe and the diversity of activity patterns is particularly high. Following a comparative ecological approach, for the first time activity timing is consequently treated in terms of behavioural and evolutionary ecology, providing the conceptual framework for chronoecology as a new subdiscipline within behavioural ecology. An extensive Appendix gives an introduction to methods of activity modelling and to tools for statistical pattern analysis.

There is more to biological rhythms than circadian clocks. This book aims at promoting the exciting potential of a deeper understanding of circannual, circatidal, and circalunar clocks. It highlights new developments, summarizes existing knowledge, and integrates different perspectives with the tools and ideas of diverse fields of current biology. For predominantly pragmatic reasons, research in recent decades was mostly concerned with circadian clocks. Clocks on other timescales, however, have been largely neglected and therefore still appear "enigmatic". Thanks to the rapid development of methods in molecular biology as well as in ecology, we are now able to re-approach these clocks. Laboratories around the world are showing fresh interest and substantial progress is being made in many independent projects. The book's two sections address the moon-derived circatidal, circasemilunar, and lunar cycles on the one hand (10 chapters), and the sun-derived circannual cycles on the other (6 chapters). This work brings together authors with an expansive array of expertise and study systems, ranging from tidal cycles of marine invertebrates to annual cycles of birds and mammals, and from behavioral to genetic and epigenetic backgrounds. While great challenges remain to be mastered, the book aims at conveying the excitement of unraveling, broadly, the rhythms of life.

This book provides the reader with a contemporary and comprehensive overview about the molecular, cellular and system-wide principles of circadian clock regulation. Emphasis is placed on the importance of circadian clocks for the timing of therapeutic interventions.