This project is about Comparative Neurobiology.
Ever since Charles Darwin discussed organs of extreme perfection, there have been major questions about how the vertebrate eye evolved. This project will help answer those questions.
Although it is well established that a camera-style eye, very similar to our own, must have existed for over 400 million years, it is not clear how the very simplest eye-spot of the primitive relatives of worms, urchins and sea stars transformed into the advanced eye of early vertebrates. There has therefore been a lack of direct evidence for the numerous gradations from a perfect and complex eye to one very imperfect and simple, that Darwin accepted as crucial in explaining the evolutionary origin of the vertebrate eye.
This study will draws on knowledge from varied fields, such as molecular genetics, anatomy, developmental biology, electrophysiology, and palaeontology, to establish a clear hypothesis for the sequence of events that led to the evolution of the vertebrate eye.
By concentrating on the eyes of existing tunicates, hagfishes, and lampreys, sharks, rays and chimaeras, which represent critical stages in vertebrate evolution, we will establish the following:
- a plausible scenario for the evolution of the chordate eye
- whether the hagfish eye is a missing link between a simple light detector and an image-forming camera-like eye
- the origins of bright light (cone-based photopic) vision and dim light (rod-based scotopic) vision
- the implications of the research for helping to resolve a century old controversy, namely how hagfishes, lampreys and the remainder of the jawed vertebrates (gnathostomes) are related.
We are also investigating the visual systems of species of a range of jawed vertebrates such as birds and mammals (marsupials and monotremes), in order to trace the evolution of colour vision and the selection pressures underlying how animals see in specific light environments.