Locomotion and buoyancy in water

characteristics of water?

more dense and viscous, incompressible, less O2

advantages in living in water

increased buoyancy with grater density, more force, effect of gravity reduces

disadvantages in living in water

increased drag b/c of increase viscosity, more energy to swim through water

what forces act on swimming fish?

thrust vs drag, lift vs gravity

what shape are fish?

fusiform

what are homocercal?

symmetrical tail that produces forward thrust

what are heterocercal?

asymmetrical tail that produces forward thrust and rotational force

what do the large pectoral fins do?

balance the rotational force made by the fins

what are the ways to swim?

anguilliform, carangiform, thunniform, rajiform, ostraciiform

what is anguilliform?

whole body generates thrust

what is carangiform?

posterior half generates thrust

what is thunniform?

tail generates thrust

what is rajiform?

undulating distal parts of pectoral fins

what is ostraciiform?

tail oscillation

what does thunniform swimming do?

efficient and fast

what are the characteristics of flying fish?

modified pectoral fins, rigid body, developed spine, glideing

why are fish neg boyant?

bone, cartilage, proteins denser than water

why is maintaining position in water column important?

temp, O2, light, food, predators

why is dynamic lift expensive?

requires forward movement and induces drag

what is unique about hammerheads?

dorsal fin is longer than pectoral fins

what does swimming on the side do?

increases wingspan and optimizes ratio between lift and drag

what is static lift?

buoyancy without muscular effort

how does static lift work?

dense materials reduced, oils stored in liver, lipids in bone

what do swim bladders do?

keep fish afloat

physostomous swim bladder

connected to digestive tract, need to stay near surface

physoclistous swim bladder

disconnected from gut, works underwater, pumps O2 from gas gland, O2 reabsorbed by oval area

what are characteristics of the oval area?

lots of blood, well vascularized, reabsorbs O2