1. Bony Fish Class osteichthyes

2. VARIETY: WHY

3. Many body shapes:

4. Streamlined shape reduces drag

5. Hinged tail increases swimming efficiency

6. Scales: Thin and overlapping Thin and overlapping Covered by layer of skin and mucus Covered by layer of skin and mucus Grow as the fish grows Grow as the fish grows

7. Coloration: Chromatophores: color cells Chromatophores: color cells Irridophores: shiny cells Irridophores: shiny cells

8. Muscle: Red vs. white Myoglobin=stores oxygen in muscles Myoglobin=stores oxygen in muscles Red muscle=more myoglobin=more swimming! Red muscle=more myoglobin=more swimming! White muscle=less myoglobin=slow! White muscle=less myoglobin=slow!

9. Osmoregulation: blood is less salty than ocean Drink water Drink water Kidneys Kidneys Gills (chloride cells) excrete salt Gills (chloride cells) excrete salt

10. Digestive organs: Pyloric ceca: digestive gland Pyloric ceca: digestive gland Intestine length: Intestine length: –Long=plant material –Short=“meat”

11. Temperature regulation Poikilotherms (most) Poikilotherms (most) Pseudohomeotherms (some): temp kept slightly higher than water (muscles make heat energy) Pseudohomeotherms (some): temp kept slightly higher than water (muscles make heat energy)

12. Gills are efficient Low oxygen content in water Many gill filaments to increase surface area Active fish have more gill surface area (up to 10 times the body surface area!) Extract up to 85-90% of oxygen in water You extract about 20%

13. Counter Current Flow in Gills Water and blood flow in opposite directions within the gill space Diffusion occurs: oxygen into blood and Carbon dioxide out of blood

14. Fish countercurrent flow: gills

15. Oxygen flow into blood: dots represent oxygen flowing into blood

16. Operculum: pump to increase efficiency Bony plate helps to pump water over the gills Removes need to SWIM to respire: allows hovering, etc. and different shapes evolved Some fish like tuna have an operculum that no longer pumps; water is forced over the gills by fast swimming (Ram Gills)

18. Swim Bladder Allows fish to be NEUTRALLY BUOYANT Allows fish to be NEUTRALLY BUOYANT May be open to the pharynx and air enters here (pneumatic duct); gulpers /surface fish may do this May be open to the pharynx and air enters here (pneumatic duct); gulpers /surface fish may do this Has a gas gland/rete mirable to get gas into the bladder Has a gas gland/rete mirable to get gas into the bladder

19. Rete Mirable Chemical reactions cause blood to release oxygen into the swim bladder: Lactate levels in the blood increase  pH levels drop  hemoglobin releases oxygen which then diffuses back into the incoming capillary until oxygen pressure is greater than that of the swim bladder  oxygen enters SB

20. Dr Seuss’s Law: One fish two fish Red fish blue fish!!

21. Boyle’s Law: Up fish out gas/down fish/in gas Fish swims up/pressure decreases/gas expands/fish must let gas out! Fish swims down/pressure increases/gas contracts/fish must let gas in!

22. Swim bladder used to make sounds Grunt

23. Croaker

24. Puffer

25. Crevalle Jack

26. SENSES Smell: (nares/olfactory sacs) Color vision (cone cells) Touch/vibrations (neuromast cells: hairlike cells that detect motion Taste (cells on lips, mouth, barbels) Hearing (otoliths or ear stones for vibrations) Balance: semicircular canals

27. Why Variety? What structures have led to such variety? 1. 2. 3. 4.