1. Chapter 30
Fish

2. 360 to 400 million years ago-

4. These are the most primitive vertebrates.
Jawless Fish
These are the most primitive vertebrates.
            
A hagfish.

5. A sea lamprey.

7. Lamprey on trout

8. IV.  Fishes
            A.  Vertebrate jaws evolved from skeletal supports of
   Jaws and fins allowed fish to become active in pursuit of food and in biting off chunks of flesh.
Members of group are chondrichthyes and osteichthyes. They have two pairs of fins.

9. Respiratory Structures
Gills
Made of feathery thread-like structures called filaments. Each filament contains a network of capillaries for the exchange of oxygen and carbon dioxide.
Fishes exchange gases by pulling oxygen-rich water in through their mouths, pumping it over their gill filaments, and then pushing oxygen-poor water out through gill openings.

10. Circulation in fish
Two chambered heart

12. 360 to 400 million years ago- the “Age of Fishes”
 Two groups are alive today: Class Chondricthyes:  Sharks and Rays have cartilaginous skeletons.
Skin made of denticles
Nerve center
Stream lined body
Rigid Pectoral fins used for lift
Liver secretes oil to change depth

13. Shark Skin
Shark skin feels like sandpaper because it has small scales known as denticles.  It is often dried and used as a leather product or sandpaper. Denticles are homologous in structure to teeth, and are what gives the skin a rough feeling.

15. Ampullae
Counter shading

17. Osteichthyes: “bony fishes”
Paired fins that move independently
swim bladder to change depth quickly
lateral line: line of sensitive nerve endings
Scales for protection and flexibility
Ray finned

19. Great Lakes Some of the natives Lake trout Whitefish Sturgeon
Ray finned
Great Lakes
Walleye
Some of the natives

20. Lobe finned fishes Coelacanth

21. Sea to land

22. Excretion.. Lol c: Kidney
Helps control the amount of water in their bodies.
Fish in saltwater tend to lose water, so their kidneys concentrate the waste in the form of ammonia, which contains very little water and helps control water loss.
Fish in freshwater tend to gain water, so their kidneys produce very dilute urine which contains an abundance of water.

23. Fish
Spawning: females laying eggs and males fertilizing them externally
Roe: fertilized fish eggs
Milt is the seminal fluid
from males that fertilizes
The eggs
Fry: baby fish

24. Reproduction Internal or external fertilization.
Oviparous- Female lays the eggs and the embryos in the eggs develop and hatch outside her body.
Ovoviviparous- The eggs stay in the mother's body after internal fertilization and embryo develops inside egg and obtain nourishment from the egg; the young are “born alive”.
Viviparous- The embryos stay inside the mother’s body after internal fertilization and obtain nourishment from mother’s body, not egg; the young are “born alive”.