fish

How do fish remove high amounts of oxygen from the water?

There is a short diffusion distance, large surface area at gill site, counter current exchange of gases, large volume of water passes over

What is the gill ventilation process?

1. Mouth opens, expanding volume of gill chamber

2. Mouth closes, creating pressure difference

3. Water moves over gill cavities as the chamber compresses and water is expelled

How does the countercurrent exchange work?

Water moves across gills in the opposite direction of blood flow, oxygen diffuses along entire length of lamellae because blood with low O2 always meets water with high O2, allows for diffusion of high O2 in water to low O2 in blood

What are some secondary respiratory structures?

Diffusion of O2 from water into skin capillaries, connection of swim bladder to esophagus, lungs - modified swim bladder, vascularized region in roof of mouth, vascularized stomach or intestinal wall

What is branchial ventilation?

Through the mouth, pharynx, operculum branchiostegals

What is ram ventilation?

Same parts but not same pumping energy, mostly in sharks, once swimming speed is achieved no need to vent buccal cavity

What behaviors and functions rely on/are influenced by chemoreceptors?

Finding prey, avoiding predators

How do fish improve olfactory sensitivity?

What are pharyngeal jaws?

A second set of jaws on the base of the skull with teeth to grind up plant material

What are the 3 main strategies fish use to deal with sinking?

Reduce body weight i.e. cartilage instead of bone, add gas/swim bladder (hydrostatic organ), generate lift via heterocercal tail and planing fins, avoid the problem via living on the bottom

What is physostomus?

Swim bladder open to the outside, primitive, these fish need to gulp air to descend and release gas to ascend

What is physoclistous?

Swim bladder is sealed, derived, volume of gas increases and decreases through secretion or resorption of gases to or from blood

What adaptations help fish hear better?

1. Swim bladder magnifies sound, swim bladder is connected to inner ear

2. Cephalic & lateral line system, consists of neuromasts, which are hair cells that produce impulses when bent in a direction

Explain positioning of the lateral line

Surface fishes usually have a lateral line located ventrally presumably to warn of rising predators, bottom fishes usually have elevated lateral lines to warn of predators from above

Internal fertilization vs external fertilization