The Evolution of the Eye Georg Glaeser Hannes F. Paulus The Evolution of the Eye Georg Glaeser · Hannes F. Paulus The Evolution of the Eye Georg Glaeser Hannes F. Paulus Universität für Angewandte Kunst Wien Department für Integrative Zoologie Wien, Austria Universität Wien Wien, Austria Translation from German language edition: Die Evolution des Auges - Ein Fotoshooting by Georg Gla eser and Hannes F. Paulus © Springer Spektrum/Springer-Verlag Berlin Heidelberg 2014 Springer Spektrum/Springer-Verlag Berlin Heidelberg is a part of Springer Science+Business Media ISBN 978-3-319-17475-4 ISBN 978-3-319-17476-1 (eBook) DOI 10.1007/978-3-319-17476-1 Library of Congress Control Number: 2015949439 Springer Cham Heidelberg New York Dordrecht London © Springer International Publishing Switzerland 2015 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, express or implied, with respect to the material contained herein or for any errors or omissions that may have been made. Printed on acid-free paper Springer International Publishing AG Switzerland is part of Springer Science+Business Media (www.springer.com) V The evolution of the eye Tokay gecko (Gekko gecko) VI Seahorse (Hippocampus reidi) Preface VII While it may be impossible to photograph evolution per se, we may certainly photograph its results. Many famous prod- ucts of evolution emerged independently across wildly dif- ferent species, but nevertheless share functional or morpho- logical features – often for very interesting reasons. Hence, a focus on specific organs or bodily parts is often especially useful, leading to additional, fascinating insights that a broader view would have missed. This book is a cooperation between an evolutionary biologist and a mathematician who also happens to be a passionate nature photographer. We aim to illuminate the vast field of evolutionary biology, wielding images and text with equal importance. The majority of photographs were taken by Georg Glaeser, who aimed to depict the numerous animals with empathy and artistic grace, rather than with dispassionate scientific objectivity. The images on this spread are a good example of his approach – details emerge spontaneously at the expense of „zoological clarity“, allowing even seasoned biologists to notice remarkable features or patterns of behaviour that would be missed on purely scientific images. As a species, we rely disproportionately on our eyesight – a predilection that makes us prone to judging by appearance. Sea horses and giraffes may be extremely different animals, and yet, one would be hard-pressed to deny a superficial resemblance beyond the mere difference in size. Some even conclude, on the basis of appearance alone, that humans have fish-like ancestors – but looks may be deceiving, and our naive intuitions are often mistaken. Incidentally, evolutionary biology has already settled the question of what caused the giraffe‘s famous neck to grow so long: it did not evolve, as it is often believed, because the animals fed on trees that grew their foliage on increasingly higher branches in a desperate arms race to survive in the African savanna. Rather, their necks seem to have been molded by the ubiqui- tous mechanism of sexual selection. In writing this book, we have attempted to give many examples along the various branches of the evolutionary tree. Our special focus always lies on the ways in which eyes have evolved. We have attempted to illuminate this gradual development from many perspectives, comparing the many strikingly different results of this billion-year process through Giraffe (Giraffa camelopardalis) VIII Tarsier (Tarsius spec.) IX pictures and schematic illustrations. Since photographs play such an important part, the textual descriptions have been condensed to their essence. However, we have attempted to provide a broad scope of additional information through foot- notes and related publications, including websites. This book is accompanied by a website of its own, where changes to the referenced websites are tracked and remedied whenever possible. This book does not have to be read from front to back – in fact, it encourages a “coffee table” style of reading. However, we have tried to make jumping from chapter to chapter easier by including an extended glossary towards the end, which con- tains explanations of the most important terms, followed by an index for situations when even the glossary does not suffice. We aim to present the staggering diversity of eyes in the animal kingdom – from stalk eyes to point eyes, facet eyes, and lens eyes. The simplest form of eyes already appears in single-celled organisms, which may possess a photoreceptor at the base of their flagellum, which allows them to distinguish dark from light. However, it is remarkable to notice that eyes are largely irrele- vant to forms of life that do not possess a clear anterior (head, eyes, and feeding tools) and posterior (organs of excretion). We would like to thank the following people for their valued cooperation on this book – in alphabetic order, omitting their academic titles: Daniel Abed-Navandi, Gudrun Maxam, Axel Schmid, Manfred Walzl, and Sophie Zahalka. Ms. Stefanie Wolf from Springer Spektrum Verlag has supervised the project with great engagement. Finally, we would like to thank Peter Calvache for his work on graphics design, layout, production, as well as for his translation from German to English. Due to the limited number of pages available to us, we have had to select the printed photographs very carefully. Many interesting pictures didn‘t make the cut, but can still be found on this book‘s official website: www.uni-ak.ac.at/evolution Western long-tailed hermit (Phaethornis longirostris)