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29-1Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Chapter 29: Animal movement
29-2Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Locomotion as a key to animal life• All animals move at some stage in their life cycle
– example: sponges are sessile as adults but have motile larvae
• Locomotion requires the exertion of force on the surrounding environment– land, air, water
• Two categories– muscular– non-muscular (cilia, flagella)
29-3Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Living in water• Buoyancy
– tendency for an object to float– interaction between upthrust () and gravity ()
• Positive buoyancy– object rises ( > )
• Negative buoyancy– object sinks ( < )
• Neutral buoyancy– object remains in position ( = )
29-4Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Positive and negative buoyancy• Positive buoyancy
– overall density of organism lower than that of water– example: Physalia with gas-filled float
• Negative buoyancy – overall density of organism greater than that of water– example: benthic organisms
• Both require organisms to expend energy to remain at a constant depth– not rise or sink
29-5Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Neutral buoyancy• Neutrally buoyant organisms have an overall
density the same as that of water• Neutrally buoyant animals have mechanisms for
changing overall body density• Reduces the energy expenditure associated with
maintaining vertical position
29-6Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Neutral buoyancy (cont.)• Gas-filled structures
– Nautilus shell chambers– fish swim bladders
• Gases can be excreted or secreted to allow animal to vary buoyancy
• Some sharks have high levels of lipid in liver to reduce overall density– slight negative buoyancy
29-7Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Fig. 29.1: Nautilus(a)
(b)
Copyright © Mike Tinsley/AUSCAPE
29-8Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Non-muscular locomotion• Cilia and flagella only effective in small organisms
– protists– many invertebrate larvae
• Extensions of cytoplasm exert force on water– multiple cilia– one flagellum or several flagella
29-9Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Fig. 29.2: Beating of a cilium
29-10Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Muscular locomotion• Jet propulsion
– expelling water to push animals in opposite direction
• Rowing – moving forelimbs backwards and forwards in oar-like
movements
• Body undulations– trunk muscles and tail fin used to propel animal
• Underwater flying– flapping forelimbs in flight movements
29-11Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Travelling through air• Flying animals use
– unpowered flight little energy expenditure gliding parachuting
– powered flight substantial energy expenditure muscle-powered flapping
29-12Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Unpowered (gliding) flight• Gliding animals extend body surface to increase lift• Force of lift depends on
– speed of flight– size of wing (aerofoil)– shape of wing– tilt (angle of attack) of wing
• Gliding requires minimal energy expenditure– maintenance of posture
29-13Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Gliding• Most gliding animals can alter shape of gliding
surface to modify performance– speed decreased for landing– speed increased in intercepting prey
• Soaring is employed by birds that use powered flight – gliding on thermals rising from warm land
• Slope soaring– soaring in wind rising along a slope, so bird remains
stationary relative to ground
Fig. 29.10: Hovering
29-14Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Fig. 29.11: Gliding
29-15Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
29-16Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Powered flight• Requires significant energy expenditure to flap
wings– but more efficient than terrestrial locomotion
• Downstroke acts against air to provide lift and thrust– wing fully extended to maximise lift and thrust
• Some birds and bats hover by producing lift on downstroke and upstroke– high energy expenditure– hovering restricted to small animals
29-17Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Moving on land• Techniques for terrestrial locomotion are varied
– without legs (protists, soft-bodied invertebrates) amoeboid locomotion peristalsis pedal waves
– with legs (invertebrates, vertebrates) crawling walking jumping
29-18Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Locomotion without legs• Amoeboid movement
– single-celled organisms extend finger-like pseudopodia over substrate
• Peristalsis– segmented worms typically use peristalsis to crawl and
burrow– interaction of muscles and hydrostatic fluid change shape
of segments
• Pedal waves– waves of muscular contraction on underside of snail’s
foot
29-19Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Locomotion with legs• Legs raise body off ground to decrease amount of
body in contact with ground• Reduced contact decreases stability• Stability increased by
– lower centre of mass– increased area of contact (larger feet, more limbs)– larger area enclosed by contact points
29-20Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Walking and running• Animals change gaits at different speeds
– example: horses walk trot gallop
• Energy expenditure increases with increasing speed
• Within each gait there is a speed at which energetic cost is minimal
29-21Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Jumping• Kangaroos use pentapedal (four limbs + tail)
locomotion at low speeds• Hopping is more efficient than pentapedal
locomotion at higher speeds
Fig. 29.12: Metabolic costs of transport
29-22Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
29-23Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Skeletons• Skeletons provide
– support for muscles– support against gravity
• Types of skeletons– hydrostatic
fluid-filled
– exoskeleton rigid, external
– endoskeleton rigid, internal
29-24Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Hydrostatic skeletons• Soft-bodied animals (deformable body wall)• Fluid-filled body cavity• Action of muscles shunts water around one or
more cavities, changing shape of body• Body capable of extension and contraction
– example: annelid (segmented) worms
29-25Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Exoskeletons• External skeleton of chitin (+ minerals in some
species)• Thick and rigid plates (sclerites), thin and flexible
between plates• Muscles attached to inside of skeleton• Must be moulted periodically to allow growth
29-26Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Endoskeletons• Internal skeleton of cartilage and/or bone
– bone can be remodelled to accommodate changed loads– increases in mass in response to increased loads– decreases in mass in response to decreased loads
• Muscles attached to outside of skeleton• Endoskeleton grows with the organism
29-27Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Joints• Exoskeletons and endoskeletons both have rigid
components• Joints allow flexibility between the components
– muscle produces force– bones or other skeletal elements act as levers
• Joints can be classified by degree of mobility– sutures are fixed and immovable (e.g. skull)– slightly movable joints (e.g. intervertebral discs)– freely movable joints (e.g. elbows, shoulders)
Fig. 29.20: Joint structure
29-28Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
29-29Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Muscle structure• Skeletal muscle cells (fibres) are cylindrical,
multinucleate and have a striated (striped) appearance– striations due to arrangement of actin and myosin
filaments in sarcomeres
• Infoldings of sarcolemma (muscle fibre plasma membrane) ramify through fibre– transverse (T) tubule system
29-30Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Fig. 29.22a: TEM of mammalian skeletal muscle
29-31Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
How skeletal muscle works• Mechanism of skeletal muscle contraction is
explained by the sliding filament model• Actin filaments slide relative to myosin filaments
– draw Z-discs towards centre– shorten sarcomere– muscle contracts
29-32Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Sliding filaments• When resting, myosin heads are unable to form
cross-bridges with actin• Myosin binding sites blocked by tropomyosin• When an action potential depolarises sarcoplasmic
reticulum, Ca2+ binds to troponin-tropomyosin complex, exposing myosin binding sites
• Myosin binds to actin filament
29-33Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Sliding filaments (cont.)• Change in shape of myosin head draws actin
filament towards centre of sarcomere• Binding of ATP to myosin head causes it to detach
and return to ‘primed’ state• It reattaches at another binding site further along
actin filament
29-34Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Fig. 29.24 (top): Mechanism of muscle contraction
29-35Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Fig. 29.24 (bottom): Mechanism of muscle contraction (cont.)
29-36Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Skeletal muscle fibre types• Type I fibres
– slow oxidative or slow-twitch fibres
• Type IIA fibres– fast-oxidative or fast-twitch, fatigue-resistant fibres
• Type IIB fibres– fast glycolytic or fast-twitch, fatigable fibres
• Type IIX fibres– intermediate between IIA and IIB
29-37Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
Slow- and fast-twitch fibres• Force-production of characteristics of a fibre in
response to stimulation• Fast twitch fibres
– contraction lasts about 10 ms
• Slow-twitch fibres– contraction lasts about 100 ms
• Distribution of muscle types depends on function of muscle– Type I (slow-twitch) fibres in postural muscles– Type IIB (fast-twitch) fibres in arms and shoulders
Summary• Various forms of locomotion have evolved in
animals• Aquatic locomotion is achieved by an animal
exerting a force on the surrounding water • All types of flight employ some type of aerofoil of
which its size, shape and orientation determine performance
• Support and stability are important for animals whose bodies are raised off the ground
• Movement requires muscles to work against skeletons
29-38Copyright 2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and SaintSlides prepared by Karen Burke da Silva, Flinders University
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