ZOO 2090 Lecture Notes - Lecture 7: Keratin, Deep Sea Fish, Lamprey

• School: University of Guelph
• Department: Zoology
• Course: ZOO 2090
• Professor: Fred Laberge

Document Summary

Describe functional variation of the fish integument the basic structure and functional variation in fish integument evolution of fish scales. Typical exam question: contrast the different types of fish scales using diagrams of scale cross sections. Show bone, dentin, and enamel content for one example of each: cosmoid, placoid, ganoid, and elasmoid scale. Development ectoderm forms epidermis, mesoderm (dermatome) forms dermis pigment cells (chromatophorms) migrate from neural crest. Functions of integument physical barrier -> protects against injury, pathogens, desiccation, respiration, excretion (co2, urea), osmotic regulation thermoregulation (on land) odours and colour used in courtship of defense: etc jack of all trades . Variation across groups: number and complexity of glands, differentiation of the stratum corneum, extent of bone development in the dermis. Glands: many unicellular and some multicellular mucous glands, mucus prevents entry of foreign materials, likely reduces drag and may include substances toxic to predators other multicellular glands, photophores (bioluminescence in deep sea fish, poisonous glands (stingrays)