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Marine Vertebrates: Fishes (part 2). Fishes. Phylum Chordata Subphylum Vertebrata 3 Classes: Class Agnatha (jawless fishes) Class Chondrichthyes (cartilaginous fishes) Class Osteichthyes (bony fishes). Fishes - Anatomy. Cartilaginous fishes: Ventral mouth
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Marine Vertebrates: Fishes (part 2)
Fishes • Phylum Chordata • Subphylum Vertebrata • 3 Classes: • Class Agnatha (jawless fishes) • Class Chondrichthyes (cartilaginous fishes) • Class Osteichthyes (bony fishes)
Fishes - Anatomy • Cartilaginous fishes: • Ventral mouth • Heterocercal tail (caudal fin) • Placoid scales “dermal denticles”
ctenoid cycloid Fishes - Anatomy • Bony fishes: • Terminal mouth • Homocercal tail • Cycloid or ctenoid scales
Fishes - Anatomy • Cartilaginous fish skeleton: http://www.marinebiodiversity.ca/shark/english/images/porbeagle%20skeleton%20for%20web.jpg
Fishes - Anatomy • Bony fish skeleton: http://www.infovisual.info/02/img_en/034%20skeleton%20of%20a%20fish.jpg
Fishes - Buoyancy • Bony fish – swim bladder (gas) • Cartilaginous fish – • Swim, get lift from stiff fins • Large, oil-filled liver • Cartilage half as dense as bone
Fishes - Locomotion • Muscle up to 75% of body weight • Muscle bands – myomeres (flake when cooked) • Red muscle – sustained swimming • White muscle – burst swimming http://www.buschgardens.org/infobooks/BonyFish/images/muscle.gif http://www.earthlife.net/fish/muscles.html
Fishes - Locomotion Homocercal caudal fins by shape: Slowest→ ← Slow Fast→ ← Fastest Heterocercal caudal fins: http://www.buschgardens.org/infobooks/BonyFish/images/caudalfi.GIF http://www.dfw.state.or.us/mrp/salmon/FishID/Heterocercal.jpg http://static.howstuffworks.com/gif/willow/flying-fish-info0.gif
Fishes - Locomotion Swimming modes:
Fishes - Locomotion Built for speed – Pacific sailfish has high speed bursts 70+ mph
Fishes - Respiration Bony fish (more efficient) Cartilaginous fish • 5-7 pairs of gills • Gill slit openings • 4 pairs of gills • Operculum gill cover
Fishes - Respiration • Spiracles important for rays when buried http://elasmodiver.com/images/Cortez-round-stingray-04.jpg http://blogs.southflorida.com/citylink_dansweeney/Southern_sting_ray.jpg
Fishes - Respiration • Gills maximize oxygen diffusion: • High surface area • Counter-current flow (oxygen concentration of water always higher than blood)
Fishes - Respiration • “Warm-blooded” fish: • Epipelagic sharks, tunas, billfishes • Counter-current flow retains muscle heat • Body surface stays water temperature • Body core has elevated temperature
Fishes - Feeding Large mouth, tear chunks or swallow fish whole Small mouth, small prey Large mouth, filter feeder (plankton) Small mouth, small prey Hard beak, graze algae and coral
Fishes - Feeding • Largest species: • Whale sharks (up to 60 ft) • Basking sharks (up to 50 ft) • Filter feeders (eat plankton) Whale (Rhincodon typus) Basking (Cetorhinus maximus)
Fishes - Osmoregulation Equal solutes by adding urea Lower solutes, water loss
Fishes – Sensory Organs • Vision • Taste buds • Smell – olfactory sacs, nostrils • Sound – inner ear, otoliths (bones) http://www.marinebiodiversity.ca/otolith/english/images/cod6oto.jpg http://www.ncdc.noaa.gov/paleo/pubs/andrus2002/otolith-md.gif
Fishes – Sensory Organs • Vibrations – lateral line (for hearing, too)
Fishes – Sensory Organs • Electroreception – ampullae of Lorenzini (cartilaginous fishes only) small holes http://www.seaworld.org/infobooks/Sharks&Rays/images/ampullae.gif
Fishes – Schooling • Use senses to coordinate (vision, sound, lateral line) • Protection from predation • Safety in numbers • Visual confusion • Feeding • Mating • Swimming efficiency http://image03.webshots.com/3/4/24/9/6942409XjGFEFguyY_ph.jpg http://image14.webshots.com/14/5/22/94/170152294GjijRv_fs.jpg
Fishes – Reproduction • Fertilization • External – bony fishes • Internal – cartilaginous http://www.gloversreef.org/grc/spawning.jpg http://www.flmnh.ufl.edu/fish/education/questions/claspers.jpg http://www.pbs.org/wnet/nature/files/2008/10/286_lifeed_behind1.jpg http://www.charkbait.com/article/Scan5sm.jpg
Fishes – Reproduction • Development • Oviparous (most bony fishes, some cartilaginous): • External eggs, yolk http://www.ufz.de/data/bioindicator-fish-eggs2455.jpg
Fishes – Reproduction • Development • Ovoviviparous: • Internal eggs, yolk, live-birth • Viviparous: • Internal eggs, nutrition from mother, live-birth http://www.west.asu.edu/achristie/hsw4kids/animals/sharks/birtha.jpg
Fishes – Reproduction • Asexual – parthenogenesis (“virgin births”) • Very rare • Female sharks in captivity • Female offspring (genetic clones) Bonnethead – 2001 Black-tip – 2008 http://marinebio.org/upload/_05/Sphyrna_tiburo1.jpg http://www.sciencedaily.com/images/2008/10/081010173054-large.jpg
Fishes – Reproduction • Strategies • Many small eggs (tarpon – 100 million eggs each spawn) • Fewer large eggs (more work) http://www.soc.soton.ac.uk/GDD/hydro/atmu/ecology/chapter5/sgtmjr.jpg
Fishes – Development • Planktonic fish larvae http://www.coralreeffish.com/larvae.htm
Fishes – Development • Coastal fish use estuaries as nurseries