30-2 Fishes BIO 1004 Flora

What is a Fish? Aquatic vertebrate Paired fins, scales and gills Function of parts – Gills – respiration – Scales – protection – Fins - movement

Fish Anatomy/Feeding Types of feeders includes: – Herbivores – Carnivores – Omnivores – Parasites – Filter feeders – detritivores

Fish Anatomy Pyloric ceca – specialized structure in fish that helps them further digest food Gills – site of gas exchange – Made of structures called filaments – Filaments have a rich supply of blood through capillaries are attached – Breath oxygen rich water through mouth, pump it across gills, and breath out oxygen poor water through openings in the pharynx ** Operculum protects the gills

Anatomy Cont. Circulation – Have a closed circulatory system with a heart – Single loop system – Heart has 3 chambers Sinus venosus, atrium, bulbus arteriosus (includes ventricle) SV, A, V, BA, gills, body, back to SV

Response Well developed nervous system Most fish have highly developed sense organs Have color vision as good as our own Lateral line system – detects gentle currents and vibrations in the water with sensory receptors

Movement Muscle contract on one side of body or other and causes s-shaped curve to move down body Most fish bodies are more dense that the water around them (sink) Fish are equipped with swim bladders, which is a gas filled organ, that adjusts their buoyancy. – Located just beneath backbone

Reproduction Eggs of fishes are fertilized externally or internally (depending on species) Fishes whose eggs hatch outside their body are called “oviparous” Fishes whose eggs stay inside a mom’s body after fertilization is called “ovoviviparous” Viviparous – obtain nutrients from mother - not a yolk sac – Also born alive

Groups of Fishes Jawless – No teeth or true jaws – Lack vertebrae – Ex: lampreys or hag fishes Sharks/relative of sharks – Skeletons are built entirely of cartilage, not bone – Scales (rough) – Lots of teeth Bony fishes – Skeletons are made of hard calcified bone