1. Subphylum Vertebrata Phylum Chordata
Fishes
Subphylum Vertebrata
Phylum Chordata

2. Classes Superclass Agnatha (jawless)
Class Myxini
Class Petromyzontida
Superclass Gnathostomata (have jaws)
Class Chondrichthyes
Class Actinopterygii
Class Sarcopterygii

3. Class Myxini Hagfishes Scavengers
Feed on Annelids, Molluscs, crustaceans and dead or dying fish
Very developed senses of smell and touch
Almost completely blind
No paired appendages
Biting mouth has two rows of
eversible (to turn inside out)
teeth, but no jaws

4. Class Petromyzontida Lampreys Free living or parasitic
Reproduce in winter or spring in streams
Males build nest
Female uses mouth to hold onto stone to position over nest releasing eggs
As eggs are shed into nest, they are fertilized by male
Adults will die soon after
2 dorsal fins, no paired appendages
Cartilaginous skeleton

6. Class Chondrichthyes Cartilaginous skeleton 2 subclasses:
No bone is present, even though their derived ancestors have well developed bone
It was believed to have been lost through a process called neoteny – phosphatized mineral tissues were retained in teeth, scales and spines
2 subclasses:
Elasmobranchii
Holocephali

7. Subclass Elasmobranchii
Sharks, Skates, Rays
Although most sharks are timid, they can be very dangerous to humans
Great white shark, mako shark, tiger shark, bull shark and the hammerhead sharks
Dorsal (top) and Caudal (tail) fins provide thrust and some lift as it sweeps back and forth
They have paired pectoral and pelvic fins (side fins)
Have upper and lower jaws filled with sharp teeth

8. Sharks and their prey
Can detect prey from a kilometer or more away, using their olfactory senses
Prey can also be located by sensing low-frequency vibrations
As the prey gets closer, sharks will switch to vision
Contrary to popular belief, sharks have excellent vision
Use their electroreceptor's to detect prey in the final moments of the attack.

9. Subclass Holocephali Ratfish, spookfish, ghostfish, Chimaeras
Today only 33 species exists
Upper jaw is completely fused to cranium
Food consists of seaweed, molluscs, echinoderms, crustaceans and fishes

10. Class Actinopterygii Ray-finned fishes Boney fish Single dorsal fin
Earliest evidence of this class indicates a heterocercal caudal fin (similar to those of a shark)
3 subclasses
Cladistia
Chondrostei
Neopterygii

11. Types of caudal tails

12. Subclass Cladistia Bichirs have lungs heavy ganoid scales most ancient

13. Subclass Chondrosteans
Sturgeons and paddle fish
Recently, populations have declined due to dam construction, overfishing and pollution
Sturgeon
Paddlefish

14. Subclass Neopterygians
Bowfin and Gars
Led to the modern boney fish, teleosts
Needle-like teeth
Gulp surface air
Filling their swim bladder with air to supplement oxygen obtained in the gills
Gar
Bowfin

15. Teleosts 27,000 species described – great diversity
Represent 96% of all living fishes or about half of all vertebrates
Eels, catfishes – completely lost gills
Other species have gills that are thin, light and flexible
Increase speed and motility
Have a homocercal caudal fin permits greater speed
Dorsal fin is now flexible and can have specialized function
Adaptations to jaws
Sliding of upper jaw to increase final attack velocity
Act as a suction device
Chewing, grinding and crushing

16. Eels
Giant Catfish pounds
Normal Catfish

17. Class Sarcopterygii Rhipidistians, lung fishes, coelacanths
Early ancestors had lungs as well as gills, and heterocercal tails
However, now has evolved to have a diphycercal tail
Powerful jaws
Heavy enameled scales
Lungfish- some lungfishes can live out of water for periods of time
In order to survive dry periods, the lungfish may create a slime mixed with mud to form a cocoon
Lungfish