BIOL 1108 1st Edition Lecture 9Outline of Last Lecture I. Geologic ErasII. FishIII. Fish FormsIV. Fish Evolution and ClassificationV. Ostracoderm Characteristics VI. Superclass: Gnathostomata Outline of Current Lecture I. Gnathostomata AdvantagesII. Early Gnathostomes III. Modern Boney Fish IV. Characteristics of Most Teleosts V. Natural History of Fish Current LectureI. Gnathostomata Advantages- Greater diversity of foods- Greater defense o Active- bite or snapo Passive- threat display- Allows manipulation of objects - Paired Appendages: development of limbsII. Early Gnathostomes - Class Placodermi: Placodermo “plate-skinned”o Formed during the Silurian Era - Class Acanthodii: Acanthodiano “spiny sharks”- fins supported by spines o Boney operculum These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.o More modern looking, diverse o Cartilaginous skeletono Not ancestors of sharks III. Modern Boney Fish- Class: Sarcopterygii (lobe-finned bony fishes)o Subclass: Coelacanthimorpha- Coelacants Mezozoic Era (Cretaceous) Latimera chalumnae : thought to be extinct o Subclass: Dipnoi- Lungfish Not as diverse any more Fleshy fins Ability to breath atmospheric oxygen with lung-like structures Not ancestors to modern tetrapods o Subclass: Osteolepimorphi- ripidistian fishes Ancestors to modern tetrapods Predatory, now extinct Shallow, freshwater habitats Morphological structures similar to early amphibians - Class: Actinopterygii (ray-finned bony fishes)o Subclass: Chondrostei Order: Acipenseriformes- Paddlefish and Atlantic Sturgeon Order: Polypteriformes- Birchirs and Ropefisho Subclass: Neopterygii Division: Teleostei (90% of all fish)- Variation in locomotion, reproduction, ect.- Ex. Trouts, bass, catfish, ect. - Class: Chondrichthyes (cartilaginous fishes) developed early on o Largely marine predatorso Elasmobranchii and Holocephali IV. Characteristics of Most Teleosts1. Cycloid/ Ctenoid scales 2. Tail usually homocercal3. Possess a swim bladder V. Natural History of Fish - Fish breathe using gillso Efficient absorbing oxygen through water counter-current exchangeo Consist of gill arches and gill filaments/ primary lamellae o Secondary lamellae- projections on the primary lamellae (increases surface area) Counter-current flow: water flow and blood flow are in opposite directions High percentage oxygenated water coming to contact with low oxygenated blood Gradient tendency to flow from water to blood (high to low
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