Week 9 - Aquatic, Aerial, Terrestrial Locomotion

Lift

counteract effects of gravity; vertical plane

Thrust

forward movement; horizontal plane

white fish muscle

up to 90% of muscle, few mitochondria, good for bursts

red fish muscle

endurance, more mitochondria, used for cruising, little fatigue

Providing lift in aquatic vertebrates

swim bladder, low density body structure, fins

anguilliform movement

most of body used to produce thrust, eel movement

carangiform movement

front half rigid, back half produces waves and contractions

ostraciiform

only caudal fin involved in thrust

appendicular movement

appendages used for swimming

undulatory

use fin in undulations, more than one wave present on fin at a time

oscillatory

use back and forth movement of appendages

Roll

tendency to move side to side (think of pencil rolling down a hill)

Pitch

tendency to go up and down (think forward/backward roll)

Yaw

tendency to go right or left (think pivoting on an axis in a scanning motion)

Drag

counteracts thrust

viscous drag (aquatic)

friction between body and water

inertial drag (aquatic)

turbulence as fish moves and disperses water

To reduce drag in aquatic vertebrates

body covering (smooth skin/mucus), body shape (streamline)

challenges of flight

less dense medium than water, generate thrust/lift, reduce drag, counteract instability and gravity

provide lift in aerial vertebrates

shape of wing (camber), angle of attack (increase to a point)

Alula

notches between primary feathers, smooth out and reattach air flow

Bernoullis principle

air moves faster above the wing, this creates lower pressure above the wing, generating lift by drawing the wing up

Providing thrust in birds

flight stroke, asymmetrical primary feathers

frictional drag (aerial loco)

friction between body and air

pressure drag (aerial loco)

air hitting front of wing

induced drag (aerial loco)

air vortices on wingtip

reduce drag in birds

well preened feathers, streamline body, long tapered elliptical wings

static soaring

typical in vultures, broad high-lift wings, use thermals and updrafts to maintain altitude

dynamic soaring

typical in seabirds, very long slender wings, use strong winds in oceans to gain height

powered flight

use own muscular power to take off and remain airborne, convergently evolved three times in vertebrates

Cursorial locomotion

running, different gaits and foot postures

plantigrade

walk on sole of foor and palm of hand (bears, apes, humans)

digitigrade

walk on digits (birds, dinos, most carnivores)

unguligrade

only tips of digits (nails) touch the ground (horses, deer)

Saltatorial locomotion

jumping, bipedal or quadrepedal

scansorial locomotion

climbing, specialized structures to increase grip (setae, lamellae)

serpentine

crawling type, lateral undulation, anguilliform movement on land

rectilinear

crawling type, straight line movement, used by heavy bodied snakes

concertina

crawling type, anchor part of body with s-shaped coils, pull body forward, anchor again, stretch out body

side-winding

crawling type, throw body 2-3 coils at a time, fast

lasso

crawling type, snake wraps around tree trunk to ascend vertically, newly discovered

digging

found in verts with fossorial habits, adaptations for power or reduced/lost limbs

speed vs power

maximize speed by having high Lo/Li ratio

maximied power with a low ratio

Lo

limb length

Li

limb protrusion / olecranon process

Adaptations for speed

increased limb length, flexibility of spinal column, unsupported intervals, reduce distal weight on limbs, increase rate of stride