| Popis: |
Organisms depend on sensory input to survive and thrive. Vision is a key sensory system to many vertebrates, including ray-finned fishes (Actinopterygii). Sight is enabled by the retina composed of cone and rod photoreceptors, each characterised by its own set of opsin proteins that together with the chromophore form the photo-sensitive pigment. Vision is energetically very costly and so it is often adapted to specific photic conditions to best match available wavelengths of light. This Ph.D. thesis focuses on the evolution and development of opsin gene expression in ray-finned fishes. It mainly aims to explore how ontogenetic differences of visual capabilities across the fish phylogeny relate to ecological conditions. In some species, ecological shifts between developmental stages can affect their physiology, including vision. In this thesis I focused on the molecular differences of the visual system between developmental stages, mostly focusing on larvae and adults. The first chapter of the thesis focuses on developmental changes in deep-sea fishes, a unique group of organisms that has evolved unconventional adaptations to maximise photon capture in an otherwise photon- depleted environment. Most deep-sea fishes start their lives in the shallow, sun-lit, predator and food abundant epipelagic... |
