Chapters: 3

Fish, Amphibians, Reptiles and Birds

Phylum Chordata (Chordate)

All have backbone Vertebrates – subphylum Shared Characteristics:

Notochord Dorsal nerve chord Gill slits Endoskeleton Closed circulatory system

1. Notochord

Rod of cells above the central nervous system (CNS)

Most chordates have as embryos

Develops into backbone

2. Dorsal Nerve Cord

Becomes a brain and spinal chord

hollow

3. Gill Slits

In embryo stage Disappear except in

fish

4. Endoskeleton

Internal skeleton Advantage – ability to

grow without molting

5. Closed Circulatory System

2, 3,4 Chambered hearts

Benefit – more oxygen Blood contained in

blood vessels

5b. Chambered hearts

6. Other characteristics of Chordates

Complex nervous system

Varied locomotion Tail extends beyond

anus Gills or lungs

Vertebrate Classes

Fish

Fish characteristics: Aquatic (fresh and Salt) Paired fins for

movement Scales Gills Various feeding

methods (herbivores, carnivores, parasites, filter feeders)

Fish Digestion

Pathway of food: Mouth Esophagus Stomach (partially

broken down) Pyloric cecum – secrete

digestive enzymes and absorption

Fish Digestion continued

Food does not pass through Liver – Pancreas –

Both secrete chemicals to break down food

Fish Circulation

Closed circulatory system

2 chambered heart Atrium – oxygen poor

blood from body Ventricle – pumps

blood to gills

Fish sense organs

Have a well-developed brain

Eyes – color vision Strong sense of taste

and smell Lateral line – sense

motion of other fish

Groups of Fish

Group 1:Jawless Fish examples- lampreys and

hagfish - simplest - cartilage - tubular - sucker mouth Nostrils – only one Produce slime 7 gills – not covered parasites

Group 2: Cartilaginous Fish

Examples: sharks and rays - cartilage skeleton Tooth-like scales on skin - jaws with 1000’s of teeth - acute senses of vision,

smell, and vibrations - breathes by swimming - internal fertilization

Skates and Rays Bottom feeders Filter feeders Vacuum like mouths

Group 3: Bony Fish

largest group of fish - skeleton of bone - swim bladder-

maintains depth - external fertilization

(spawning)

Importance of Fish

ecology of water - food source (Fish are

friends not food-Bruce-Finding Nemo)

- hobby and sport

Amphibians

“Double Life”

Characteristics of Amphibians

Live in water when young and to reproduce

Live on land as adults Breath through skin No scales Have lungs External fertilities!

Additional Amphibian Characteristics

Ectotherms – organisms whose body temp is controlled by the outside temp. (cold blooded) Dormant in cold

environments

More amphibian characteristics

Amphibians are the link between land and water animals

Groups of Amphibians

Frogs and Toads Short, broad bodies Sing to attract males Sticky tongue to catch

food Acute vision Hearing – tympanic

membrane, Powerful hind legs

Toads

Found in dryer environments

Life cycle of frogs and toads