1. Classes: Agnatha, Chondrichthyes, and Osteichthyes
FISHIES
Classes:
Agnatha, Chondrichthyes, and Osteichthyes

2. Fish are the dominant aquatic vertebrates.

3. Fish have adaptations to an aquatic environment that make their movements through water energy-efficient.

4. Arapaima South American Freshwater Fish

5. Internal Anatomy of Bony Fish

6. Gills
Large sheets of thin frilly tissue filled with capillaries that take in dissolved oxygen from the water and release carbon dioxide.

7. Circulatory system: pumps blood in a single loop through a two chambered heart.

8. Countercurrent Flow
The opposite movement of water against the flow of blood in the fish’s gills.
Maximizes the amount of oxygen the fish can pull from the water.

9. Swimming and Maneuvering
Most fish swim by contracting large segmented muscles on either side of their body from the head to the tail.
This makes an S-shaped wave that pushes it through the water.
They counteract these movements with their fins.

10. External Anatomy of Bony Fish

11. Fins Surfaces that project from a fish’s body Keep the fish stable
Direct the movement of the fish

12. Fins

13. Jawless Fish Class Agnatha
Existed since the Cambrian and continues to live
Do not have paired fins
Have a notochord in both larvae and adults
Light sensitive pineal eye
No identifiable stomach
Ectothermic
Two-chambered heart
External Fertilization

14. Sea Lamprey Petromyzon marinus

15. Hagfish Myxine glutinosa

16. Jaws Evolved from gill arches
Most jawed vertebrates have teeth on their upper and lower jaws.
Teeth used to capture and process food

17. Jaws
Gave vertebrates a huge advantage as predators and pushed them to the top of the food chain.

18. Two groups of jawed fish still exist:
Cartilaginous Fish
and
Bony fish

19. Cartilaginous Fish
Skeletons made of cartilage while ancestors had skeletons made of bone
They have lost the ability to make bone
Cartilage is unique – it’s stronger than human cartilage.

20. Two Groups of Cartilaginous Fish
Holocephali: chimeras
Elasmobrachs: sharks, rays and skates

21. Holocephali: chimeras
Small group of deep-sea fish with platelike grinding teeth.
Feed on crustaceans and other invertebrates

22. Elasmobranchs: sharks, rays and skates
300 species of sharks
400 species of rays and skates
Ray Skate

23. Sharks
Most hunt other fish
Some eat seals and sea lions

24. Filter feeder, eats plankton
Biggest Sharks
Whale Sharks
Feed on plankton, krill
and algae
Basking Sharks
Filter feeder, eats plankton

25. Great White Shark

26. All Fish Have a lateral line system
This is a series of shallow canals on the sides of the fish made up of cells that are sensitive to small changes in water movement.
This allows them to have a sense of “distant touch”.

27. External Anatomy of Bony Fish

28. Class Osteichthyes Bony Fish
More than 20,000 species
Living in nearly every aquatic environment on Earth
Some have become parasites of other fish
One group can even spend short periods of time on land

29. Characteristics internal skeleton ossified (i.e., endochondral bone)
swim bladder or lung present
bony scales (ganoid, cycloid, ctenoid, or cosmoid)
gill slits covered by an operculum (single external gill opening)
late Silurian to Recent

30. Seahorse Genus Hippocampus
Unique because males become pregnant when the females deposit the eggs into the birthing pouch.

31. Nile Knifefish Will aggressively bite anything that moves
Discharges an electrical charge