1. FISHES

2. Phylum Chordata
Contains ALL fishes, amphibians, reptiles, birds, and mammals
ALL chordates have a notochord;
- a flexible rod that supports a chordates back (all embryonic, some retain, some change)

3. CHARACTERISTICS Cold blooded Paired Fins Gills, Scales
EVOLUTION OF FISHES
Agnathans – jawless, 1st vertebrae, round mouth for sucking or filter feeding
Jaws (from gill arches) = Gnathostomes! & Paired fins improved swimming and feeding
Cartilage Skeletons (Sharks, Rays, Skates – still considered vertebrates) – Class Chondrichthyes
Bony Skeletons (Modern Fish) – Class Osteichthyes

4. FORM & FUNCTION Feeding
Everything you can imagine – carnivores (“big teeth”), herbivores (pharyngeal bone – small “teeth” on jaw, omnivores (random), detritivores (mouth on bottom), parasitic (“suckers”)
Respiration
Hard bony flap covering the gills - operculum
Air breathers
Obligate – must breathe air or will die (African Lungfish)
Facultative – whatever is convenient (some Catfish)
Usually found in tropical waters – because…
Circulation
Closed Circulatory System, Single Loop
Atrium --Ventricle -- Gills -- Body -- Back to Atrium

6. Osmoregulation – balance of water levels in body
- Salt water fish tend to lose water & gain salt - Fresh water fish tend to gain water & lose salt - Homeostasis maintained by the kidneys
Brain Responses
- Cerebrum - thinking, voluntary activities - Cerebellum - coordination - Medulla Oblongata - functions of internal organs - Lateral Line System - senses vibrations
Movement
- Very muscular – make great swimmers and good food - Swim Bladder - buoyancy

7. Reproduction Ovoviviparous (eggs stay in mom)
Oviparous (lays eggs)
Ovoviviparous (eggs stay in mom)
Viviparous (babies get nourishment from mom. Ex. Humans, cats, some fish)

8. Classes of Fish Class Myxini: “Jawless Fish”
EX: hagfish and lampreys
Class Chondreichthyes: “Cartilaginous fish”
EX: sharks, rays, chimaeras
Class Osteichthyes: “Bony Fish”

9. Class Myxini Hagfish and Lampreys
(Mis-zini)
Hagfish and Lampreys
Slow enough metabolism that they can eat once every 6 months! (metabolism control)
They are scavengers (eat dead organisms)
Tie themselves into a knot to A) clean themselves, B) escape prey, C) pull on food
Hagfish
Lamprey’s oral disk
Lamprey
Hagfish knot

10. Class: Chondrichthyes
Means “Cartilage fish”
Skeleton composed entirely of cartilage – still considered a vertebrate
Contains ALL sharks, stingrays, skates, and chimaeras
Characteristics: jaws, paired fins, skin covered w/ placoid scales (armored fish)
Denticles: teeth-like scales, feels like sandpaper

11. 2 Subclasses Elasmobranchs: Sharks and rays
Holocephalans: chimaeras (ratfish)
Whale shark
World’s Largest Fish
Sand tiger Shark
Manta Ray
Blue Spotted Stingray
Chimaera

12. Class Osteichthyes Means “bony fish” About 25,000 spp. of bony fish
Characteristics: swim bladder, bony scales, and fin rays
2 sub-classes of fish
Sarcopterygii: Lobefin fish
Actinopterygii: Ray-finned fish

13. Sub-class: Sarcopterygii
Lobefin Fish; have round fleshy-lobes
EX: Coelacanth and Lungfish
Coelacanth: is over 400 million years old
Thought to be extinct; found in 1938
Lungfish: Lives in Africa & South America
Facultative air breathers
Lungfish gave rise to land vertebrates
Can live out of water for short time periods
Coelacanth
Lungfish link
Lungfish
Lungfish walking!

14. Sub-class: Actinopterygii
Ray-finned fish; most numerous group
Fusiform body shape: stream-lined allows fish to move through watch w/ great efficiency
Scale types
Ganoid: Thick bony scales that don’t overlap
Cycloid: Thin, smooth overlapping scales
Ctenoid: Thin, spiny overlapping scales
Perch
Lookdown

17. Fins ___________: on the top of fish used for stability
_________: tail fin used for locomotion & stability
____________: bottom of fish used for stability
___________: used for steering (anterior)
____________: used for steering (posterior)

18. Functions Bony fish are Oviparious: (reproduce by laying eggs)
Air Bladder: gas-filled sac used to maintain buoyancy
Fish have a closed cardiovascular system
Lateral line system: canals on the side of the fish used to detect movement in the water

19. Coloration *Chromatophore: specialized cells that contain pigments
Countershading
Iridophore
*Chromatophore: specialized cells that contain pigments
*Iridophore: crystals that produces a mirror-like silver color
*Countershading: camouflage where top of fish is dark, and bottom of fish is light, used to blend into the ocean