Chapters 3 Fish Amphibians Reptiles and Birds Phylum

Chapters: 3 Fish, Amphibians, Reptiles and Birds

Phylum Chordata (Chordate) w All have backbone w Vertebrates – subphylum w Shared Characteristics: n n n Notochord Dorsal nerve chord Gill slits Endoskeleton Closed circulatory system

1. Notochord w Rod of cells above the central nervous system (CNS) w Most chordates have as embryos w Develops into backbone

2. Dorsal Nerve Cord w Becomes a brain and spinal chord w hollow

3. Gill Slits w In embryo stage w Disappear except in fish

4. Endoskeleton w Internal skeleton w Advantage – ability to grow without molting

5. Closed Circulatory System w 2, 3, 4 Chambered hearts w Benefit – more oxygen w Blood contained in blood vessels

5 b. Chambered hearts

6. Other characteristics of Chordates w Complex nervous system w Varied locomotion w Tail extends beyond anus w Gills or lungs

Vertebrate Classes

Fish w Fish characteristics: n n n Aquatic (fresh and Salt) Paired fins for movement Scales Gills Various feeding methods (herbivores, carnivores, parasites, filter feeders)

Fish Digestion w Pathway of food: n n Mouth Esophagus Stomach (partially broken down) Pyloric cecum – secrete digestive enzymes and absorption

Fish Digestion continued w Food does not pass through n n Liver – Pancreas – l Both secrete chemicals to break down food

Fish Circulation w Closed circulatory system w 2 chambered heart n n Atrium – oxygen poor blood from body Ventricle – pumps blood to gills

Fish sense organs w Have a well-developed brain w Eyes – color vision w Strong sense of taste and smell w Lateral line – sense motion of other fish

Groups of Fish w Group 1: Jawless Fish w examples- lampreys and hagfish w - simplest w - cartilage w - tubular w - sucker mouth w Nostrils – only one w Produce slime w 7 gills – not covered w parasites

Group 2: Cartilaginous Fish w w w Examples: sharks and rays - cartilage skeleton Tooth-like scales on skin - jaws with 1000’s of teeth - acute senses of vision, smell, and vibrations w - breathes by swimming w - internal fertilization

w Skates and Rays n n n Bottom feeders Filter feeders Vacuum like mouths

Group 3: Bony Fish w largest group of fish w - skeleton of bone w - swim bladdermaintains depth w - external fertilization (spawning)

Importance of Fish w ecology of water w - food source (Fish are friends not food-Bruce. Finding Nemo) w - hobby and sport

Amphibians “Double Life”

Characteristics of Amphibians w Live in water when young and to reproduce w Live on land as adults w Breath through skin w No scales w Have lungs w External fertilities!

Additional Amphibian Characteristics w Ectotherms – organisms whose body temp is controlled by the outside temp. (cold blooded) n Dormant in cold environments

More amphibian characteristics w Amphibians are the link between land water animals

Groups of Amphibians w Frogs and Toads n n n Short, broad bodies Sing to attract males Sticky tongue to catch food Acute vision Hearing – tympanic membrane, Powerful hind legs

Toads w Found in dryer environments

Life cycle of frogs and toads