Over the weekend of 21-23 February 1997, a small group gathered in Tallahassee, Florida, at the invitation of Ted Williams, to discuss "photo stasis and related topics." The majority of participants were former students and colleagues of Ted's, but an occasional outsider such as myself was generously included. The papers presented there are collected in this volume. The theory of photo stasis was first outlined in a landmark paper by John Penn and Ted, published in 1986 in Experimental Eye Research. They provided compelling data showing that, in the albino rat eye, levels of rhodopsin, outer-segment length, rhodopsin regeneration rate, and even, perhaps, rhodopsin packing density all depend on the levels of cyclic illumination (12 hours light, 12 hours dark) in which the animal was reared. So, for example, there is fourfold less rhodopsin in a retinal extract derived from an animal reared at 400 lux than in an extract from the retina of an animal reared at 3 lux. Animals reared at intermediate levels of light show intermediate amounts of rhodopsin that are correlated with illumination level. What these data immediately suggested is that the photoreceptor cell can adjust its photon-catching ability in response to the levels of light in which an animal is reared, and they also provided a compelling rationale for outer-segment turnover, a phenomenon discovered 20 years earlier by Richard Young but whose function has remained obscure.

Abetted by recent technological advances in scanning and transmission electron microscopy, as well as new preparative methods, these contributions examine crustacean anatomy, demonstrating (or at least inferring) the functions of morphological features. In addition to feeding and grooming, they also

Over the weekend of 21-23 February 1997, a small group gathered in Tallahassee, Florida, at the invitation of Ted Williams, to discuss "photo stasis and related topics." The majority of participants were former students and colleagues of Ted's, but an occasional outsider such as myself was generously included. The papers presented there are collected in this volume. The theory of photo stasis was first outlined in a landmark paper by John Penn and Ted, published in 1986 in Experimental Eye Research. They provided compelling data showing that, in the albino rat eye, levels of rhodopsin, outer-segment length, rhodopsin regeneration rate, and even, perhaps, rhodopsin packing density all depend on the levels of cyclic illumination (12 hours light, 12 hours dark) in which the animal was reared. So, for example, there is fourfold less rhodopsin in a retinal extract derived from an animal reared at 400 lux than in an extract from the retina of an animal reared at 3 lux. Animals reared at intermediate levels of light show intermediate amounts of rhodopsin that are correlated with illumination level. What these data immediately suggested is that the photoreceptor cell can adjust its photon-catching ability in response to the levels of light in which an animal is reared, and they also provided a compelling rationale for outer-segment turnover, a phenomenon discovered 20 years earlier by Richard Young but whose function has remained obscure.

This work is the first to focus systematically on a much-debated topic: the conceptual issues of community ecology, including the nature of evidence in ecology, the role of experiments, attempts to disprove hypotheses, and the value of negative evidence in the discipline. Originally published in 1984. The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These editions preserve the original texts of these important books while presenting them in durable paperback and hardcover editions. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905.

This work is the first to focus systematically on a much-debated topic: the conceptual issues of community ecology, including the nature of evidence in ecology, the role of experiments, attempts to disprove hypotheses, and the value of negative evidence in the discipline.

Originally published in 1984.

The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These paperback editions preserve the original texts of these important books while presenting them in durable paperback editions. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905.