Different types of moving about
- aquatic locomotion
- terrestrial locomotion
- aerial locomotion
Annelid locomotion
- use their hydrostatic skeleton for locomotion - displacement of coelomic fluid elongates body towards direction of motion
- circular and longitudinal muscles
- peristalsis - waves of contraction and expansion
- parapodia - used by polychaete worms to crawl or swim
Mollusc locomotion: cephalopods
fin swimming: pair of lateral fins, undulations of fins propel animal forward through water
- jet propulsions: most common, use mantle wall muscles to eject water from a funnel, can be directed in most directions controlling movement
- slow jetting: contraction of the circular muscles expels water from mantle cavity
- fast jetting: escape response, contraction of radial muscles hyperextend mantle cavity so it contains more water
- flying: soot out water to glide for a distance, squid spread out tentacles to form wings
- walking: benthic octopus walk along sea floor using suckered arms
Mollusc locomotion: pulmonate gastropods
- series of waves move along surface of the foot and interacts with layer of mucus propelling the animal forward
- crawling speed has a positive relationship with pedal wave frequency, mean wavelength and foot length
Aquatic locomotion in fossil panarthropods
- fossil stem arthropods lack segmented limbs as in true arthropods but had flaps along each side of the body
- opabinia: depositional environment indicates they lived on the sea floor
- Anomalocaridiae: large predatory stem arthropods with segmented bodies, no segmented limbs, paired flaps, probably swam by undulating flaps
Trilobite locomotion
- one pair of walking limbs on each segment
- scuttle along sea floor, churning up sediment as they move
Invasion of land by arthropods
- fossil trackways from euthycarcinoids
- Cambrian period
Moving in the air in invertebrates
- insects are the only invertebrates to attain ariel locomotion
- direct flight or indirect flight
Locomotion in echinoderms
- tube feet
- part of WVS with each tube foot attached to the ampulla
- tube feet extend and retract
Aquatic locomotion in fish
- swimming: lateral undulations, muscles contract on one side and relax on the other
- types: anguilliform, sub-carangiform, carangiform, thunniform, ostraciiform
- two types of drag: viscous and pressure
- drag overcome by having streamlined bodies
- fast fish have rough scales to generate turbulence and forked fins that minimise surface area
Terrestrial locomotion in basal amniotes
- three types of postures: sprawling, semi-erect, erect
- wide sprawling gait with large lateral movements
- common ancestor of mammals was likely crouched whereas reptile ancestor likely had sprawling posture
Terrestrial locomotion in reptiles
- sprawling posture with a wider gait and large lateral movements
Ariel locomotion in birds
- passive flight: gliding and soaring
- powered flight: flapping
- four forces act on birds wings: lift, drag, gravity, thrust
- cambered cross-section
- powerful muscles –> pectoralis powers the downstroke, supracoracoideus powers the upstroke
- hollow, lightweight bones
- wing shape associated with different types of flight
What are pterosaurs?
- presence of an enlarged fourth finger that supports a wing membrane
- unique flight adaptations –> hollow bones, air sacs, large powerful forelimb
- powered flight
Terrestrial locomotion is mammals
- non plantigrade foot posture: plantigrady, digitigrady, unguligrady
- plantigrady: stand and walk on entire foot from toe to heel, limbs abducted and flexed in small mammals, high degree of flexibility and utility of digits
- digitigrady: stand and walk on toes, more upright limb posture, support weight through foot pads, heels not touch ground, increased lower limb length
- unguligrade: stand and walk on tips of toes, weight supported by unguals through hooves, further increased lower limb strength
Graviportal adaptations
large bodied mammals show these:
- columnar limbs
- longer proximal limb elements over distal elements
- slower movements
Scaling for plantar forces and pressure
- plantar force and pressure increases more than expected with increasing body size
- contact surface area increases as expected with increasing body size
- correspond to anatomical and behavioural adaptations in larger mammals
- foot pads help dissipate plantar pressures
