FISH (ch30-2)

CHARACTERISTICS

- Aquatic
- Paired Fins
- Gills, Scales

EVOLUTION OF FISHES

- 1st Fish were jawless
- Devonian Period - "Age of Fishes"
- Jaws & Paired fins improved swimming and feeding
- Cartilage Skeletons
- Bony Skeletons (Modern Fish)

FORM & FUNCTION

Feeding
- Heterotrophs (carnivores, herbivores, omnivores, detritivores, parasitic)

Respiration
- Gills and Gill Covering (operculum)
- Lungfishes (air-breathers)

Circulation
- Closed Circulatory System, Single Loop
- Atrium --Ventricle -- Gills -- Body -- Back to Atrium

Excretion
- Salt water fish tend to lose water
- Fresh water fish tend to gain water
- Homeostasis maintained by the kidneys

Response
- Cerebrum - thinking, voluntary activities
- Cerebellum - coordination
- Medulla Oblongata - functions of internal organs
- Lateral Line System - senses vibrations

Movement
- Paired Fins
- Swim Bladder - buoyancy

FINS
Caudal
Dorsal
Anal
Pelvic
Pectoral

Reproduction
- Oviparous (lays eggs)
- Ovoviviparous (eggs stay in mom)
- Viviparous (babies get nourishment from mom. Ex. Humans, cats, some fish)

Groups of Fish

Kingdom Animalia
Phylum Chordata
Subphylum Vertebrata

2 Classes of Jawless fish:
- Lamprey (parasitic)
- Hagfish (scavenger)
- Both have cartilage skeleton

Class Chondrichthyes
- Cartilage Fish
- Sharks, stingrays
- Most are predators
- Basking sharks are filter feeders
- No swim bladder, pectoral fins rigid

Class Osteichthyes
- Bony Fish
- Ray-finned ( Goldfish, Bass, Carp, Salmon )& Lobe Finned ( Coelacanth )