1. MARINE FISHES
THE FIRST VERTEBRATES

2. Oldest and simplest vertebrates Most abundant vertebrates
Three groups of fishes
Jawless fishes
Cartilaginous fishes (Chondrichthyes)
Bony fishes (Osteichthyes)
Yes, it is FISHES- the rule is fish is for a single individual or more than one individual of the same species
FISHES- refers to more than one species

3. Jawless fishes Class Agnatha Around 30 known species
Includes hagfish & lampreys
Feed by suction with aid from teeth
No fins, & lack true vertebrae; no scales
Body is elongated and cylindrical
Most primitive fishes

7. Cartilaginous Fishes Class Chondrichthyes Skeleton made of cartilage
Movable jaws
Mouth ventral
Underneath the head
Paired lateral fins
Sandpaper-like skin because of Placoid Scales
Includes sharks, rays, skates, and ratfishes

9. SHARKS ~350 living species Upper lobe longer than lower lobe
Caudal Fin is Heterocercal
Upper lobe longer than lower lobe
Fusiform, or spindle-shaped bodies
Five to seven gill slits
Powerful jaws with rows of teeth that are Continuously replaced
Carnivores & Filter Feeders
Found most often in warm
coastal water
Most only live in marine env.
Some travel upstream

16. SKATES AND RAYS ~450-500 known species Dorsoventrally flattened
Demersal: fish that live on the bottom
Five ventral gill slits
Stingrays
Whip-like tail with stinging spines
Electric Rays
Electric organs on each side of head
Skates lack the stinging tail

18. Ratfish: AKA Chimaeras
~30 known species
Only one pair of gill slits covered by a flap of skin
Long, rat-like tail

20. Bony Fishes Class Osteichthyes ~23,000 known species
Skeleton made of bone
Cycloid or Ctenoid Scales
Operculum: Gill Cover
Upper & lower tail fin same size: Homocercal

21. Homocercal tail Cycloid scales

22. BONY FISHES

24. Fin Rays: thin membranes supported by bony spine
Anterior, terminal mouth
More flexible jaws with teeth attached to jawbone
Swim Bladder: gas-filled sac above stomach & intestines that helps in buoyancy

25. BIOLOGY OF FISHES

26. BODY SHAPE ICHTHYOLOGY- study of fish
Body shape varies with habitat and lifestyle
Fast swimmers are streamlined- like tuna, marlins, mackerels, sharks

27. Dorsoventrally flat- skates, rays and sea moths- demersal fish (live near bottom)
Dragon sea moth
Image from
Liveaquaria.com

28. Laterally flattened bottom dweller fish such as flounder, halibut and sole
Born with eyes on both sides of body but as they mature, one eye migrates to the dominant side

29. Elongated bodies such as eels- live in narrow places amongst rock and coral reef

30. Laterally compressed bodies live around coral reefs, kelp beds etc.
Butterfly fish
snappers

31. COLORATION
CHROMATOPHORES-skin cells that contain pigments; irregular in shape with branches radiating out from the center of the cell
STRUCTURAL COLORS-Colors that result when light is reflected by a particular surface
Many times caused by IRIDOPHORES- chromatophores with light-reflecting crystals

32. Colors reflect mood
warning coloration- coloration that allows organisms to escape from predators by advertising something harmful or distasteful video
cryptic coloration-color pattern that allows an organism to blend in its surroundings- video
Disruptive coloration- a color pattern that helps break the outline of an organism
Ornate cowfish
Disruptive coloration

33. COUNTERSHADING- a color pattern that results in a dark back and a light belly- most common in epipelagic fishes (surface to 200 m)