FISH

I. Characteristics of Fish A. Fish are over 1/2 the vertebrates on Earth.

The internal skeleton allows vertebrates to grow larger than invertebrates.The internal skeleton allows vertebrates to grow larger than invertebrates.

The backbone of vertebrates provide support and protect the dorsal nerve cord.The backbone of vertebrates provide support and protect the dorsal nerve cord.

B. The study of fish is called ichthyology.

C. Fish are adaptive for living in water.

SchoolSchool –fish have comfortable swimming room. PodPod –fish bodies touch as they swim.

EctothermicEctothermic –cold-blooded. Cannot control their body temperature.Cannot control their body temperature. EndothermicEndothermic –warm-blooded. Maintain a constant body temperature.Maintain a constant body temperature.

1. have gills for breathing. 2. have paired fins & streamlined shape for easy movement.

3. have skin covered with scales 4. Most have lateral line system

a. Lateral line system is a row of sensory structures that run the length of the body on each side.

b. Lateral line system detects vibrations & chemicals in the water.

II. Three Classes of Fish

A. Class Agnatha - Jawless Fish 1. Examples

a. Lamprey 1. parasites 2. feed on blood 3. locate prey with sense of smell

Lamprey

b. Hagfish 1. scavengers 2. feed on dead or dying fish

2. Characteristics of Class Agnatha a. mouth is a ring b. slimy skin with no scales

c. Good sense of smell d. some are parasites e. some are scavengers

B. Class Chondrichthyes - Cartilage Fish 1. Examples

a. Sharks b. Rays 2. General Characteristics of Class Chondrichthyes

a. skeleton made of cartilage not bone b. most are carnivores - meat eaters

c. skin is covered with placoid scales - tooth like spines which make it feel like sandpaper

Hammerhead

3. Characteristics of Sharks a. upper portion of tail is longer than lower portion.

b. has 6 to 20 rows of backward pointing teeth which can be replaced if worn down or broken

Megalodon Teeth

c. sharp sense of smell- can detect blood in water up to 500 meters (546 yards) away

d. most must move constantly to pass water over their gills (NO swim bladder). e. eggs are fertilized internally.

1. Males have modified fins called claspers that carry sperm through grooves into the female.

2. Most females give live births; others lay large yolky eggs.

4. Characteristics of Rays a. have flattened bodies with wing- like fins

b. are bottom dwellers c. feed on mollusks & crustaceans d. have barbed stinger on the end of its tail for defense

Puffer Fish

C. Class Osteichthyes 1. Examples a. perchb. bass c. troutd. tuna

Poisonous Lion Fish

2. About 95% of all fish belong to this class. 3. Types of bony fish a. Lobe-finned

1. have paddle like fins 2. Example - a.Coelacanths

b. Lung Fish 1. have lungs & gills 2. live in shallow tropical ponds that dry up in summer

3. bury themselves in mud until ponds refill c. Ray - finned 1. live in all waters

2. most numerous of all fish

FINS Dorsal-keeps upright.Dorsal-keeps upright. Caudal- propels.Caudal- propels. Pelvic- steers.Pelvic- steers. Pectoral- steers.Pectoral- steers. Anal- steers.Anal- steers.

Raising and lowering the fins help fish regulate body temperature.Raising and lowering the fins help fish regulate body temperature.

SWIM BLADDER a.k.a. gas bladdera.k.a. gas bladder –acts like a float as it fills up with gas to go higher and lower in the water. –Lacking in cartilage fish.

External Adaptations Chromatophores- color pigments.Chromatophores- color pigments. Countershading- dark on top;light on bottom.Countershading- dark on top;light on bottom. Operculum- shield over the gills.Operculum- shield over the gills.

HEART (2 chambers) ATRIUMATRIUM –receives blood from the body. VENTRICLEVENTRICLE –pumps the blood.

BRAIN Cerebrum- instincts.Cerebrum- instincts. Cerebellum- muscle coordination.Cerebellum- muscle coordination. Olfactory-smell.Olfactory-smell. Optic- sight.Optic- sight. Medulla oblongata- internal organs.Medulla oblongata- internal organs.

DIGESTIVE Liver- makes bile.Liver- makes bile. Gall bladder- balloon-like sac that stores bile.Gall bladder- balloon-like sac that stores bile. Spleen- blood reservoir.Spleen- blood reservoir. Pancreas- secretes insulin.Pancreas- secretes insulin.

REPRODUCTION SPAWNINGSPAWNING –process of laying eggs by the female and releasing sperm (MILT) over them by the male.

Gone Fishing