marine vertebrates marine biology dr. ouida meier
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Marine Vertebrates
Marine BiologyDr. Ouida Meier
Representative Marine Phyla:
• Phylum Porifera
• Phylum Cnidaria
• Phylum Bryozoa
• Phylum Mollusca
• Phylum Annelida
• Phylum Arthropoda
• Phylum Echinodermata
• Phylum Chordata
Phylum Chordata
• Subphylum Urochordata– Class Ascidiacea (tunicates)– Class Thaliacea (salps, gelatinous
thaliaceans)
• Subphylum Vertebrata – this week.
All chordates possess at some time during development a notochord (made of cartilage) along midline of body, below a hollow dorsal nerve cord, as well as a postanal tail and pharyngeal pouches.
Subhylum Vertebrata
• Class Agnatha (jawless fish)
• Class Chondrichthyes (cartilaginous fish)
• Class Osteichthyes (bony fish)
• Class Reptilia (reptiles)
• Class Aves (birds)
• Class Mammalia (mammals)
Subphylum Vertebrata
• Class Agnatha (jawless fish)
• Class Chondrichthyes (cartilaginous fish)
• Class Osteichthyes (bony fish)
• Class Reptilia (reptiles)
• Class Aves (birds)
• Class Mammalia (mammals)
Features of Vertebrates
• Postanal tail, pharyngeal pouches (chordate)
• Vertebral column (develops from notochord; segmented)
• Specialized sensory organs
• Brain at anterior end of nerve cord
• Closed-loop circulatory system (heart, arteries, capillaries, veins)
• Myomeres (muscle segments)
Marine Fish
• Agnatha – hagfish (most primitive), lampreys– [body fluids isotonic to seawater; 30-50% in other vertebrates]
• Chondrichthyes – sharks, skates, rays– [large: <20cm to >15m]
• Osteichthyes – bony fishes: tarpon, eels salmon, sardines, lanternfish, toadfish, flying fish, seahorses, pipefishes, scorpionfishes, sculpins, basses, groupers, snappers, barracudas, wrasses, tunas, triggerfishes, molas, pufferfish, etc.
– [bone stronger and lighter than cartilage; small size, diverse adaptations and habitats]
Body shape specialization:
• High maneuverability (e.g., butterflyfish)
• Rapid acceleration (e.g., barracuda)
• Efficient cruising (e.g., tuna)
• Eating methods:– Ramming (e.g., sharks)– Biting (e.g., triggerfish)– Sucking (e.g., butterflyfish)
Marine Reptiles
• Snakes (61 species of true sea snakes, most of them highly venomous)
• Turtles (7 species of sea turtles)
• Iguanas (1 species of marine iguana, Galapagos Islands)
• Estuarine environments: additional snakes, caymens, alligators, crocodiles)
Marine Birds
• Feathers and front appendages adapted for flight
• Species: range of dependence on marine environment – Ducks, geese, coots– Shorebirds: herons, stilts, sandpipers– Albatrosses, petrels, gannets, pelicans, gulls, terns, murres– Penguins
• Birds and Mammals are true homeotherms
Marine Mammals
• Order Carnivora– Pinnipeds: Seals, sea lions, walruses, sea
otters– Polar bears
• Order Cetacea– Whales, dolphins, porpoises
• Order Sirenia– Manatees, dugongs
Characteristics of mammals
• Viviparous• Body hair• Milk-secreting mammary glands• Specialized teeth• Separate reproductive / digestive tract openings
[other vertebrate groups oviparous or ovoviparous, and have a cloaca]
Modern cetaceans
• Suborder Mysticeti – [baleen whales] lack teeth; have rows of baleen projecting from upper jaw to filter-feed
• Suborder Odontoceti – [toothed whales] smaller; specialized teeth help capture slippery fish, squid, other prey
Links
• Basic background on marine mammals
• Pinniped photo gallery
• Cetacean photo gallery
• National Marine Mammal Lab, Cetacean Assessment Program
• Sea Otter Evolution and Adaptations
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