1. BrainPOP | Fish

2. Marine Fishes Structurally simplest of all living vertebrates Probably evolved from sea squirt larvae About 24,000 species known (most abundant vertebrates!) Lateral line: clusters of sensory cells that detect vibrations Usually swim with sideways undulations (“s” wriggle)

5. 1. Jawless Fishes Class: Agnatha

6. Most primitive Lack paired fins and scales Many covered with thick mucus Feed mostly on dead/dying fish Ex. Hagfishes (slime eels), lampreys

8. Life Cycle

9. Ex. Hagfishes

11. Hagfish VideoHagfish Video Hagfish Slime

12. 2. Cartilaginous Fishes! CLASS: Chondrichthyes

14. Cartilaginous skeleton and rough skin covered by “placoid” scales with a pointed tip Possess moveable jaws and paired fins Most have well-developed teeth and a ventrally facing mouth (underneath head)

16. Ex. SHARKS About 350 species Caudal fin (tail) heterocercal: the upper lobe is longer than the lower lobe

17. Pectoral fins large and pointed 5-7 gill slits behind the head

18. Range in size from 25 cm: Pygmy Shark to…

19. …to 60 feet: Whale shark!

20. RAYS / SKATES About 500 species Dorsoventrally flattened Gill slits on the underside of body Pectoral fins flat and expanded (wings) Skates: lack a whip-like tail and stinging spines, lay eggs, usually smaller Rays: possess stinging spines on tail, give live birth, usually larger

22. RATFISHES About 30 species Feed on bottom dwelling crustaceans and mollusks One pair of gill slits covered by a flap

23. 3. Bony Fishes 23,000 species, 96% of all fishes Skeleton: made at least partially of bone Ctenoid scales: thin, flexible, overlapping

24. Operculum: protective cover over gills Lobes of caudal fin are homocercal (relatively same size)

25. Most have a terminal mouth (at the end of the head) Swim bladder: gas-filled sac above the stomach which adjusts buoyancy

28. Anatomy of a shark TAIL FIN

29. External Fish Anatomy DORSAL VENTRAL ANTERIOR POSTERIOR

32. BODY SHAPE & Coloration

41. ● Epipelagic: streamlined, strong muscles, large eyes, countershading common

45. Coral Reef: laterally compressed (to fit into small spaces) also allows for speed Color: many species, helps in identification of species/mate & for warning

46. Bottom Dwellers: Dorsoventrally flattened, both eyes on top Ex: flounder, fluke, halibut, rays, skates Coloration: Usually cryptic (camouflaged)

49. Rock Dwellers: ● moray eels, trumpetfishes, pipefishes ● Distinctly elongated

50. Slow-moving bottom dwellers: ● Sculpin, blennies ● Cryptic with projections to resemble seaweed

51. Ex. Stone Fish

54. Deep Sea Fishes: relatively small, weak & flabby muscles, eyes small/absent, black, red or lack coloration, bioluminescence common

56. Ex. Deep Sea Anglerfish

57. Parasitic Male!!! Small parasitic male attaches to female for the rest of its life, obtaining nutrients from female’s blood & providing sperm

58. Many have very large mouths

59. Shark structure

60. Sharks typically have a fusiform body (rounded and tapered at both ends). This shape reduces drag and requires a minimum amount of energy to swim.

62. Most stripes and other markings are juvenile colors that fade or disappear with age, as in the case of the tiger shark

63. Shark eyes Sharks have nictitating membrane –Clear eyelid is deployed during attack to protect eyes from thrashing

64. Like its relatives, rays and skates, the shark's jaw is not attached to the cranium. The jaw's surface, like its vertebrae and gill arches, is a skeletal element that needs extra support due to its heavier exposure to physical stress and its need for extra strength. It has therefore a layer of unique and tiny hexagonal plates called "tesserae", crystal blocks of calcium salts arranged as a mosaicjawcranium

66. The Ampullae of Lorenzini are the electroreceptor organs of the shark, and they vary in number from a couple of hundred to thousands in an individualAmpullae of Lorenzini

67. Tonic immobility – YouTube Sharkman - Tonic Immobility - YouTube

69. Fish Structure

70. Gills composed of a gill arch (gives the gill rigid support), gill filaments (always paired), and secondary lamellae (where gas exchange takes place

72. The blood flows through the lamellae in the opposite direction from the water passing the gills. This is a counter current exchange system ( very important for getting all of the available oxygen out of the water and into the blood)

73. By having the blood flow in the opposite direction, the gradient is always such that the water has more available oxygen than the blood, and oxygen diffusion continues to the place after the blood has acquired more than 50% of the water's oxygen content. The counter current exchange system gives fish 80-90% efficiency in acquiring oxygen.

74. Gills pump oxygen to the 2- chambered heart

76. Vision lens of a fish eye is almost spherical (high curvature) and has a relative high refractive index this allows more light to enter the lens and produces a wide field of view

77. Tapetum lucidum amplifies light –Can see in varying light conditions