1. The Fish

2. Classification
The term “Fish” refers to three different vertebrate classes:
Agnatha—jawless fish
Chrondrichthyes—cartilaginous fish
Osteichthyes—bony fish

3. The Fish Adaptations that enable fish to be successful in the water:
stream-lined shape
muscular tail—move rapidly
paired fins—move r and l, up or down, backward or forward

4. The Fish unpaired fins on the back and belly—increase stability
mucus secretion—reduces friction when swimming

5. The Fish Fish body position:
The tissue in a fish’s body are denser than water and by controlling the amount of gas in their bodies helps to regulate vertical position (swim bladders)
They store lipids, which are less dense than water, to help them float.

6. Homeostasis Homeostasis—stable internal conditions of a living thing
Bodies of freshwater fish have a higher concentration of solutes than the surrounding water so the fish tend to gain H2O through osmosis and lose ions, such as Na+ and Cl- through diffusion

7. Homeostasis
Saltwater fish contain lower concentrations of solutes than their surroundings so the fish tend to lose water and gain ions.
Kidneys and gills play an important role in maintaining homeostasis in the tissues and ridding the body of metabolic wastes

8. Homeostasis
Some fish may move from fresh to salt water by adjusting kidney functions

9. Respiration
The presence of scales limit gas exchange through the skin, so fish rely on membranes of the gills for oxygen and carbon dioxide to diffuse
Gills are located on either side of the pharynx and are composed of feathery, threadlike structures called filaments

10. Respiration
Each filament has a network of fine capillaries that provides a large surface area for the exchange of CO2 and O2.
Fish pull O2 rich water in through their mouths, pumping it over their gill filaments and pushing the O2 poor water out through openings in the sides of the pharynx

11. Respiration
Lamprey and shark have several gill openings, but most have a single gill opening on each side of their bodies.
The opening is hidden beneath a protective bony cover called the operculum.

12. Respiration
Lungfish have an adaptation that allows them to survive in O2 poor water or in areas where bodies of H2O dry up
They have specialized organs that serve as lungs and a tube brings O2 from the air to this organ in their mouth

13. Respiration
Some lungfish are so dependent on O2 from the air that they will suffocate if they don’t reach the surface
Other lungfish can actually burrow into mud, cover itself with mucus and lay dormant for months until rain falls.

14. Feeding
Fish can be herbivores, carnivores, parasites, filter feeders, or detritus feeders (organic matter). A single fish may exhibit several modes of feeding, depending on what is available.
EX: Carp eat algae, aquatic plants, worms, mollusks, arthropods, dead fish and organic matter.

15. Feeding EX: Barracudas are highly specialized carnivores
EX: Some lampreys are parasitic.

16. Digestion
From the mouth, food passes through the esophagus to the stomach where it is partially broken down.
The pyloric ceca, in many fish, are finger-like pouches that further digest food. It secretes digestive enzymes and absorbs nutrients.

17. Digestion
The liver and the pancreas add enzymes and other digestive chemicals to the food as it moves through the digestive tract.
Intestines complete the process of digestion and absorption of nutrients.

18. Digestion
Undigested material is eliminated through the anus.

19. Excretion
Nitrogenous wastes are eliminated in the form of ammonia by diffusion through the gills into the water, or removed by the kidneys, which filter wastes from the blood
Kidneys also help control the amount of H2O in their bodies.

20. Response
Fish have well developed nervous systems, organized around a brain.
The most anterior parts are the olfactory bulbs, which are involved with the sense of smell, which is the primary sense in the fish.
They are connected to two lobes of the cerebrum. The cerebrum is responsible for all voluntary activities of the body.

21. Response Optic lobes process info from the eyes.
The cerebellum coordinates body movement.
The medulla oblongata controls the functioning of many internal organs.

22. Response Most fish have highly developed sense organs.
Almost all fish that are active in daylight have well developed eyes with color vision that is as good as ours.
Chemoreceptors are responsible for sense of taste and smell.

23. Response
Most fish have ears inside their head, they may not hear sounds well, but they can detect gentle currents and vibrations with a sensitive receptor called the lateral line system. It is a row of sensory structures that run the length of the body on each side and are connected (by nerves) to the brain

24. Response Catfish and shark can detect low levels of electric current.
The electric eel can generates its own electricity.

25. Circulation Fish have a closed circulatory system
The heart pumps blood around the body in a single loop
-heart to the gills to rest of the body and back to the heart

26. Circulation The heart consists of four parts (only two chambers)
sinus venosus—thin walled sac that collects blood from the fish’s veins before it flows to the atrium
atrium—large muscular chamber that serves as a one-way compartment for blood that is about enter the ventricle

27. Circulation
ventricle—thick walled, muscular chamber, the pumping portion
bulbus arteriosus—large, muscular tube, connects to a large blood vessel called the aorta

28. Movement
Fish move by alternately contracting paired sets of muscles on either side of the backbone, this creates a series of s-shaped curves that move down the fish’s body. As the curve travels down the body of the fish it creates a backward force on the surrounding water. This force, along with the action of the fins, propels the fish forward.

29. Movement
Fins are used to stay on course and adjust direction and provide an extra boost of speed. A swim bladder is used to adjust buoyancy and is located beneath the backbone and is an internal gas-filled organ.

30. Reproduction
Eggs are fertilized either internally or externally depending on the species.
In many species, females lay the eggs and the embryos in the eggs hatch outside the mother’s body (oviparous). Embryos obtain food from the yolk in the egg. EX: Salmon

31. Reproduction
In other species, eggs stay in the mother’s body after internal fertilization, each embryo develops inside its own egg, using the yolk for nourishment. The young are born alive (ovoviviparous). EX: guppies

32. Reproduction
A few species of fish, including several sharks are viviparous, the embryos stay inside the mother’s body, but they receive nourishment directly from the mother’s body and are also born alive.

33. Fish Classification Class Agnatha 80 species hagfish and lampreys
jawless fish, skin has neither plates nor scales
have an eel-like body and a cartilaginous skeleton with unpaired fins
notochord remains throughout life

34. Fish Classification Class Chondrichthyes
have skeletons composed of cartilage (a flexible, lightweight material made of cells surrounded by tough fibers of protein)
have moveable jaws
have paired fins
approx. 800 species of sharks, skates and rays live in salt water

35. Fish Classification all species are carnivores (some are scavengers)
that eat many different kinds of food, including fish, seals, aquatic invertebrates and plankton.
are covered with placoid scales—small, tooth- like spines that feel like sandpaper. These scales reduce turbulence in the water and increase swimming efficiency.

36. Classification Sharks
Largest sharks, the whale shark, up to 59 ft in length and the basking shark up to 49 ft in length. They eat plankton.
They have large, curved tails, torpedo-shaped bodies and pointed snouts. Sharks swim in a side to side pattern created by the motion of their asymmetrical tail fin.

37. Classification
Paired pectoral fins are located behind the head and jut out like the wings of a plane.
Their mouth has 6 to 20 rows of teeth that point inward. When a tooth in a front row breaks or wears down, a replacement moves forward to take its place. They may have more than 2000 teeth over a lifetime.

38. Classification Rays and Skates have flattened bodies
paired wing-like pectoral fins
some species have whip-like tails
rays have diamond or disk-shaped bodies, skates have a triangular body

39. Classification 3.3 ft long or less bottom dwellers
flat shape and coloration are used as camouflage on the ocean floor
feed on mollusks and crustaceans

40. Bony Fishes-ClassOsteichthyes
Period of Fish is known as the Devonian Period.
Fish were the first vertebrates to evolve and early fish were jawless and covered with bony plates.
Bony Fish are characterized by three features:

41. Bony Fish Skeleton made of bone Lungs or swim bladder
*only a few fish have lungs today (are called the lung fish)
*most have swim bladders (a gas-filled sac that is used to control buoyancy). Swim bladders are thought to have evolved from the lungs of early bony fishes.

42. Bony Fish Scales-most bony fish are covered with scales
protect the fish
reduce water resistance

43. Bony Fish Biologists have divided the bony fish into two main groups:
lobe-finned fish
ray-finned fish

44. Bony Fish
Lobe-finned fish-have fleshy fins that are supported by a series of bones, lobes are bony and rigid. Only 7 species exist today. (six species of lungfish and one species of coelacanth)
Lungfish exchange gases through the lungs and gills and live in shallow tropical ponds that periodically dry up, they burrow into the mud and cover themselves with mucus to stay moist until the pond refills.

45. Bony Fish
These fish are important because extinct lobe-finned fish are thought to be ancestors of amphibians and all other terrestrial vertebrates

46. Bony Fish
Ray-finned fish-have fins that are supported by long, segmented, flexible bony elements called rays, which are bony yet flexible. Rays probably evolved from scales. These fish are very diverse in appearance, behavior and habitat. (EX. eels, yellow perch, trout, salmon, guppies, bass, herring and darters)

47. Bony Fish
Countercurrent flow-in gills of fish, an arrangement where water flows away from the head, and blood flows toward the head, if blood and water flowed in the same direction, less O2 would be diffused