Jump to ContentJump to Main Navigation
Animal Eyes$
Users without a subscription are not able to see the full content.

Michael F. Land and Dan-Eric Nilsson

Print publication date: 2012

Print ISBN-13: 9780199581139

Published to Oxford Scholarship Online: December 2013

DOI: 10.1093/acprof:oso/9780199581139.001.0001

Show Summary Details
Page of

PRINTED FROM OXFORD SCHOLARSHIP ONLINE (oxford.universitypressscholarship.com). (c) Copyright Oxford University Press, 2021. All Rights Reserved. An individual user may print out a PDF of a single chapter of a monograph in OSO for personal use. date: 26 September 2021

The origin of vision

The origin of vision

(p.1) 1 The origin of vision
Animal Eyes

Michael F. Land

Dan-Eric Nilsson

Oxford University Press

Most of the types of eye that we recognize today arose in a brief period during the Cambrian, about 530 million years ago. The development of better eyes coincided with increases in size, speed, and armour, as visually guided predation became a common way of life. Opsin-based light sensitivity evolved in a common ancestor of all animals. Transduction mechanisms diverged early, and in the common ancestor of bilaterian animals there were at least two different types. These molecular mechanisms and corresponding genetic control networks have been modified and co-opted to form the wide range of eyes of modern animals. Eye evolution is driven by the evolution of visual tasks. Early animals could only perform few and simple behavioural tasks based on light sensitivity, but over time some animal groups acquired a growing list of ever more complex visual tasks. This development has gone from non-directional light sensitivity, via directional photoreceptors combined with body movements, to coarse spatial vision, and then to finer spatial vision with focusing optics. The evolution of advanced eyes need not have taken huge periods of geological time. It has been estimated that evolution from a patch of photosensitive tissue to an eye resembling that of a fish could have taken as little as half a million years. Eye structures responsible for spatial vision in vertebrates, cephalopods, and arthropods have evolved independently, which is now reflected in different embryologic development of eyes in these groups, and in the fundamental distinction between single-chambered eyes and compound eyes.

Keywords:   opsin, Cambrian, evolution, common ancestor, light sensitivity, transduction, directional photoreceptors, spatial vision, single-chambered eyes, compound eyes

Oxford Scholarship Online requires a subscription or purchase to access the full text of books within the service. Public users can however freely search the site and view the abstracts and keywords for each book and chapter.

Please, subscribe or login to access full text content.

If you think you should have access to this title, please contact your librarian.

To troubleshoot, please check our FAQs , and if you can't find the answer there, please contact us .