ZOO 2090 Lecture Notes - Lecture 5: Devonian, Endoskeleton, Pharyngeal Arch

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

Document Summary

Objectives describe major trends in fish evolution describe how bone and jaws enabled fishes to expand their ecological niches. Important points innovations that established fish radiations general trends of fish. Typical exam question: what is the conodont apparatus? a: complex tooth-like elements in the pharynx c. d. the jaws in the extinct group of agnathans the hyoid arches of conodonts fish scales used in stratigraphic dating. Many are parasitic use round mouth to cling onto live prey while sucking blood or clinging to substrate characteristics: metamorphosis of ammocoete larva, single nostril, seven gill openings, cartilage associated with notochord, lack bone. Conodonts (extinct: were known only from hard tooth-like elements for a long time (seen in lab!) Pituriaspida all characterized by a massive head shield and gills that opened ventrally dorsoventrally flattened shape suggests they lived at the bottom, where they probably extracted food from sediment.