Subphylum Urochordata Subphylum Cephalochordata Subphylum Vertebrata
The most diverse of all vertebrates
My research on fish * PhD Program (Oregon State University) Olfaction in coho salmon * Post-doctoral fellowship (University of Saskatchewan) Chemical communication in minnows
Month: April Ice thickness: 4 ft
Q: What is a fish?? Jellyfish Starfish Cuttlefish Shellfish Silverfish Crayfish A loosely used word!!
DEFINITION ATTEMPT: Gill-breathing, poikilothermic, aquatic vertebrate that possesses fins and has skin usually covered with scales. Dominant Vertebrate: more species (25,000) than all other vertebrates combined!! EXPERTS: Ichthyologists
Jawless Fishes ( Agnatha ) Subphylum Vertebrata Class Myxini (hagfish)
Hagfish Observations: Notochord persistant No paired appendages No Stomach Isoosmotic with seawater Naked skin
Hagfish Slime Pores
http://www.discovery.com/tv-shows/other-shows/videos/nasty-by-nature-hag-fish-slime.htm http://www.youtube.com/watch?v=bb2eop3ohne http://video.nationalgeographic.com/video/news/new-zealand-hagfish-slime-vin Hagfish Slime
enters a dead or dying animal through an orifice or by digging into the body rasps bits of flesh from its prey. *
Knotting behavior produces greater ripping force
Subphylum Vertebrata CLASS Petromyzontida (lampreys)
Lamprey Observations Notochord persistant No stomach Naked skin No paired appendages Migrate upriver to spawn Pharyngeal slits (7) Kidney that regulates water & solutes
http://www.animalplanet.com/tv-shows/river-monsters/videos/a-kiss-of-death-lamprey-sucks-jeremys-blood.htm
Cartilaginous Skeleton
Hagfish Lamprey Jawed Fish Cartilaginous Fish Bony Fish
Lamprey Life History Prolonged larval stage Both freshwater and marine species All species migrate up a river to spawn (marine species: anadromous ) Both parasitic & nonparasitic species
NOTE: Nonparasitic species do not feed as adults. Digestive system degenerates reproduce & die w/in a few months!! (or ocean) (1 3 yr) Adults die (3-7(+) yr)
CLASS CHONDRICHTHYS http://www.televisiontunes.com/jaws.html
Class Chondrichthys Subclass Holocephali Chimeras ratfish
Subclass Elasmobranchii (sharks, skates, rays) Bodies fusiform or depressed Ventral mouth Naked or with placoid scales Spiral valve Buoyancy: liver not swim bladder Isoosmotic to seawater Internal fertilization Cartilaginous ENDOskeleton notochord reduced
* Mammalian Vertebral Column *
Bony Fish Snake Class Chondrichythys All-Cartilage Skeleton (may be variably calcified)
SHARK Left pectoral fin - Pterygiophores - Ceratotrichia
Nares
Skate Skeleton Pectoral Fins
Water Flow
SHARK SKIN naris (s) nares (pl) Note countershading
Mammalian tooth Epidermis Placoid scales - are DERMAL - are modified in the mouth as teeth - are homologous to vertebrate teeth
Shark teeth fossilize cartilaginous skeletons do not
ELECTRORECEPTION Electrical Field Detection System Stephano Lorenzini (1678)
Unusual Read about the shark s surprising manner of osmoregulation
Boots Musical instruments Tablecloth Bottles of wine A bulldog s head Barrel of nails Fur coat Porcupine
Lift in the form of buoyancy: 1) Liver = 25% of body mass 80% of liver = low density fats (e.g., squalene density = 0.86 g/ml) 2) Cartilage is less dense than bone
Big Buoyant Fatty Liver
The Bony Fishes CLASS Sarcopterygii (lobe-finned fishes) Common Ancestor Tetrapods CLASS Actinopterygii (ray-finned fishes)
Extant Lobe-finned fish!! ( living fossil ) Fisherman caught one in 1938 Latimeria
Devonian Fossils Eusthenopteron lobe-fined fish from the late Devonian Period. Note pectoral fin attached to the skull. Acanthostega early Devonian tetrapod Note forelimb bones (not a strong walker)
Class Sarcopterygii Lobe-finned fishes include the extant LUNGFISH (1 species) (4 species) Neoceratodus forsteri (1 species) 1 st record: 380 mya
Swim bladder Gut Common Ancestor Lungfish Origin of Vertebrate Lungs? Lungfish
Lungfish Unbroken Notochord! (some Vertebra?)
African Lungfish Circulation
Tissues
CLASS Actinopterygii (ray-finned fishes) All typical bony fish (>25,000 species)
Diversity Of Body Shapes
Most Fish Strong vertebral column upturn Slight upturn but external symmetry No vertebral column upturn
Variation: Homocercal Tails of Bony Fish
Strongly Modified Dorsal Fins
Anchoring of Dorsal Fin body surface Muscle Tissue
Soft Rays e.g., minnow Hard Rays e.g., sunfish lateral anterior lateral anterior
Embedded Exposed Embedded Exposed Examples: Trout Minnows Perch Sunfish
Surprise?? Epidermis lies above scales * * Fish Body Wall
Catfishes have a naked skin (no scales) Super-sensitivity to dissolved amino acids 1 dot = 100 taste buds 10-9 to 10-10 M
BODY FORM
Chinook Salmon (cross-section) Vertical Septum Horizontal Septum C
Little DRAG Lots Tuna Mackerel Shark Eel Fast Tail Flip Rate Slow
http://www.youtube.com/watch?v=6lv51e-q1xu
Weight- Specific Cost of Transport (J/m/kg) Buoyancy Helps!
Novel Buoyancy
Swim Bladders - Physostomous connection to gut - Physoclistous no connection
Low-frequency Hearing in Minnows
Physoclistous Swim Bladder Adjustable Volume while submerged Physostomous Swim Bladder
No Adjustment Swim Bladder Volume Adjustment Depth Swim Bladder Volume Swim Bladder Pressure Depth
Read about lactic acid production and how blood responds
Aquatic Respiration Possibilities
Operculum Gill Arch Gill
Plankton Filter Feeders e.g., herring, shad
1 Liter O 2 1 L water BAD BAD BAD water 1 L air O 2 N
Higher Pressure Low Pressure Lower Pressure High Pressure arch 1 2 Water In Water Out
Also: RAM VENTILATION
When to Pump When to RAM? Mackerel n = 5 Fish Active Pumping Rate (cycles/sec) No Pumping = 100 % RAM Swimming Speed (m/sec)
Fathead Minnow Lamellae Filament RBCs
Physiology s Most Beautiful Principle: Countercurrent Exchange
Birds & Mammals: More Area Air: More Oxygen Gas Exchange Membrane Area (cm 2 ) Conclusion: CCE is super-efficient
Conclusion: CCE is super-efficient
Fish Blood
The Big Picture Single Loop
4 Chambers Bony Fish Heart 2 1 3 4
Blood Supply to the Heart?? Higher Vertebrates Most Fish
Some fish (salmon, tuna, sharks), some amphibians & reptiles
Warm-blooded Fish??
Counter-current Heat Exchanger Tuna Cross Section
Hydrating Environment NH 3 NH 3 Why NH 3?
Desiccating Environment
BIG BUSINESS Bass Tournament
Relative Gill Surface Areas S W I M M I N G A B I L I T Y
http://www.nature.com/news/video-fishleaps-to-catch-birds-on-the-wing-1.14496