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Chordata Group A: Agnatha , Chondrichthyes , Osteichthyes. Grace Allen Gunner Drossel Lauren Reuland. Complexity. Antropoda Segmented Bodies, Jointed limbs Exoskeleton Ventral Nerve Chords Have Brain Compound Eyes. Chordata – Fish Notochord Endoskeleton (bones) Gills
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Chordata Group A:Agnatha, Chondrichthyes, Osteichthyes Grace Allen Gunner Drossel Lauren Reuland
Complexity Antropoda • Segmented Bodies, Jointed limbs • Exoskeleton • Ventral Nerve Chords • Have Brain • Compound Eyes Chordata – Fish • Notochord • Endoskeleton (bones) • Gills • Internal Fertilization
Common Characteristics • Agnatha: Jawless • Chondrichthyes: Jawed - cartilage • Osteichthyes: Jawed – bone • All: 5 senses, fins, muscles, swim bladders (sac),
Fish Tissue • Chordata are triploblastic: • Ectoderm- epidermis/skin , pituitary gland, nasal placode, and anterior forebrain • Mesoderm- ventral (blood/connective tissues) and mesoderm (notochord and somites) • Endoderm- gives rise to digestive and resp. systems
Agnatha Reproduction • External fertilization • External development • Most species are hermaphrodites • Reproduce in freshwater riverbeds • Larvae: 4 years of development
Chondrichtyes Reproduction • Courtship and copulation • Seminal fluid injected into female • Internal fertilization • Low rate • 43% lay eggs • 1 month to 2 years gestation period
Osteichthyes Reproduction • Some are hermaphrodites • Sex reversal- males to females, vice versa • Courtship- attracting males • Spawning- gametes release in water • Copulation- direct transfer of sperm
Evolutionary Development • Cambrian Explosion- 530 mil years ago • Fossil record – jawless lineages almost extinct • Lampreys approximate ancient pre-jawed fish • First jaws found in Placodermi fossils • Advantage of hinged jaw is unclear (biting force? Improved respiration?)
Ecological Niche(s) • Chondrichthyes- oceans top predators, population control (1,000+ species total) • Agnatha – marine and freshwater environments (120 species total) • Osteichthyes- consumers, predators, scavengers in marine waters (24500+ species total)
Example 1 • LAMPREY • Petromyzontidae • Freshwater and coastal habitats • Resemble eels • Cartilaginous skeleton • Most basal group • Parasitic as adults
Example 2 • Great Hammerhead shark • Sphyrna • 9 species total • Tropical waters • Lagoons, coral reefs, continental shelves, island terraces • Endangered due to demand for meat
Example 3 • Devil Anglers • LophiusPiscatorius • Carnivorous species • Live 3000 meters below the surface • Worldwide habitats • Known as “Common Black Devil” • http://www.youtube.com/watch?v=Z-BbpaNXbxg
VIDEOS • http://www.youtube.com/watch?v=3-Zk1nd_dY8 • http://www.youtube.com/watch?v=fMTHrvskSW8 • http://www.youtube.com/watch?v=hgCKBTv03vc