- Mollusc eye
The molluscs have the widest variety of eye morphologies of any phylum, and a large degree of variation in their function. Cephalopods' eyes are as complex as those of vertebrates; scallops have up to 100 simple eyes; and some bivalves have compound eyes.
Eyes have evolved independently between seven and eleven times in the molluscs, which goes some way to explain the diversity of eye types observed. Molluscs have eyes of all levels of complexity, from the pit eyes of many gastropods, to the pinhole eyes of the Nautilus, to the lensed eyes of the cephalopods. Compound eyes are present in some bivalves, and reflective 'mirrors' have been innovated by other lineages.such as scallops. As well as complexity, the eyes of molluscs span a huge range in size; they may be from 20 µm to 27 cm across.
Gastropods and cephalopods have paired eyes on their heads (and sometimes tails), but many molluscs do not have clear head regions in which to locate the eyes. Consequently, many molluscs may have a multitude of eyes in more unlikely places, such as along the edge of their shell. Chitons have a dispersed network of tiny eyes over the surface of their shells which may act together as a compound eye. Many gastropods have stalked eyes; the eye can be retracted into the stalk itself in the presence of danger.
- ^ a b c d e f g Serb, J. M.; Eernisse, D. J. (2008). "Charting Evolution’s Trajectory: Using Molluscan Eye Diversity to Understand Parallel and Convergent Evolution". Evolution Education and Outreach 1 (4): 439–447. doi:10.1007/s12052-008-0084-1.
- ^ Land MF and Fernald RD (1992) "The evolution of eyes" Annual review of neuroscience, 15: 1–29.
- ^ Ritchie, Alexander (1985). "Ainiktozoon loganense Scourfield, a protochordate? from the Silurian of Scotland". Alcheringa 9: 137. doi:10.1080/03115518508618961.
Eyes Evolution Colouration Related topics
Wikimedia Foundation. 2010.
Look at other dictionaries:
Eye — For other uses, see Eye (disambiguation), Ocular (disambiguation), Ocular, and Oculus. For taxon specific articles, see human eye, simple eye in invertebrates, mollusc eye, and arthropod eye. Eye … Wikipedia
Mammalian eye — Eye Schematic diagram of the human eye … Wikipedia
Arthropod eye — Anatomy of the compound eye of an insect The arthropods ancestrally possessed compound eyes, but the type and origin of this eye varies between groups, and some taxa have secondarily developed simple eyes. The organ s development through the… … Wikipedia
Simple eye in invertebrates — For eye like markings, see eyespot (mimicry). Ocellus redirects here. For the Celtic god, see Ocelus. Head of Polistes A simple eye (sometimes called a pigment pit … Wikipedia
Cephalopod eye — Vertebrate … Wikipedia
Shark eye — Taxobox name = Shark eye image caption = regnum = Animalia phylum = Mollusca classis = Gastropoda ordo = Neotaenioglossa familia = Naticidae genus = Neverita species = N. duplicata binomial = Neverita duplicata binomial authority = (Say, 1822)… … Wikipedia
Turbo (mollusc) — Taxobox name = Turbinidae image caption = Turbo marmoratus regnum = Animalia phylum = Mollusca classis = Gastropoda subclassis = Prosobranchia ordo = Archaeogastropoda superfamilia = Trochacea familia = Turbinidae genus = Turbo genus authority =… … Wikipedia
Cephalopod — Cephalopods Temporal range: Devonian – Recent (Stem groups from Cambrian) … Wikipedia
Chromatophore — Zebrafish chromatophores mediate background adaptation on exposure to dark (top) and light environments (bottom). Chromatophores are pigment containing and light reflecting cells found in amphibians, fish, reptiles, crustaceans, and cephalopods.… … Wikipedia
Evolution of color vision — Color vision, a proximate adaptation of the vision sensory modality, allows for the discrimination of light based on its wavelength components. Contents 1 Invertebrates 2 Vertebrates 3 See also 4 Referen … Wikipedia