Evolution of Photoperiodism in the Threespine Stickleback Gasterosteus aculeatus

O’Brien, Conor Savage

Evolution of Photoperiodism in the Threespine Stickleback Gasterosteus aculeatus

dc.contributor.author	O’Brien, Conor Savage
dc.date.accessioned	2012-03-28T23:01:44Z
dc.date.available	2012-03-28T23:01:44Z
dc.date.issued	2011-12
dc.description	xvi, 112 p. : ill. (some col.)	en_US
dc.description.abstract	In seasonal environments, the ability to take advantage of the favorable seasons and avoid or mitigate the effects of the unfavorable ones is essential for organismal fitness. Many polar and temperate organisms use photoperiod (length of day) to time seasonal life history events because photoperiod's regular annual cycle makes it a very reliable indicator of seasonality. This reliability allows organisms to anticipate and properly prepare for seasonal change. Although photoperiodism is widespread in polar and temperate vertebrates, little is known relative to invertebrates regarding how its use varies with environment and this method's underlying genetic and physiological basis. This dissertation is focused on demonstrating the proper methodology for the study of photoperiodism and establishing the threespine stickleback as a model of vertebrate photoperiodism. Chapter I is an introduction to photoperiodism, how it is influenced by environment, the physiological basis of its output, and a summary of the chapters that follow. Chapter II explains an analytical method to test for causality and applies this method to data that have been interpreted as evidence that the circadian clock is causally involved in photoperiodism. Chapter III describes the photoperiodic response of threespine stickleback Gasterosteus aculeatus populations from two latitudes. These results are used to inform an empirical examination of the previously described assertion that the circadian clock is causally involved in photoperiodism. Chapter IV examines the physiological basis of early photoperiodic response using the threespine stickleback as a model teleost fish. Chapter V summarizes the previous chapters, describes their significance, and suggests future research directions. This dissertation includes both previously published and co-authored material. Supplementary Excel files demonstrating the analyses used in Chapter III are also included in this dissertation.	en_US
dc.description.sponsorship	Committee in charge: Eric Johnson, Chairperson; William Cresko, Advisor; William Bradshaw, Member; Judith Eisen, Member; Patricia McDowell, Outside Member	en_US
dc.identifier.uri	https://hdl.handle.net/1794/12104
dc.language.iso	en_US	en_US
dc.publisher	University of Oregon	en_US
dc.relation.ispartofseries	University of Oregon theses, Dept. of Biology, Ph. D., 2011;
dc.rights	rights_reserved	en_US
dc.subject	Genetics	en_US
dc.subject	Evolution and development	en_US
dc.subject	Physiology	en_US
dc.subject	Biological sciences	en_US
dc.subject	Life history	en_US
dc.subject	Phenology	en_US
dc.subject	Photoperiodism	en_US
dc.subject	Threespine stickleback	en_US
dc.subject	Thyroid hormone	en_US
dc.subject	Gasterosteus aculeatus	en_US
dc.title	Evolution of Photoperiodism in the Threespine Stickleback Gasterosteus aculeatus	en_US
dc.type	Thesis	en_US