Movement and Biomechanics

Question 1

Why do animals move:

Answer 1

• Food
• Reproduction
• Predator avoidance
• Environmental conditions

Question 2

Consequences

Answer 2

• Movement of organisms is a fundamental feature of life.
• Movement is central to almost all ecological and evolutionary processes.
• Affects survival, reproductive success and influences structuring of populations, communities and ecosystems.

Question 3

Movement definition

Answer 3

• A physical displacement over time.
• Movement takes place in continuous time, but we usually observe and study it in discrete time.

Question 4

Range in body size and movement speed.

Answer 4

Huge size range of motile organisms

Question 5

Size v speed

Answer 5

• Bigger animals tend to be faster, power law relationship.
• Cost of transport decreases with increasing body mass
• Animals are limited in their time for maximum acceleration because of restrictions on the quickly available energy.

Question 6

Biologging:

Answer 6

• Animal attached remote sensing, deployment of autonomous recording tags on free-living animals.
• Environmental parameters.
• Physiological parameters
• Movement parameters
• Behavioural parameters

Question 7

Geographic location tags

Answer 7

gps
argos satellite
geolocations

Question 8

GPS

Answer 8

• Determines an animal’s position.
• Error ranges between 20 and 50m.
• Typically, archival/retrieve device to get data

Question 9

• Argos Satellite (PTT):

Answer 9

• Device that communicates with polar-orbiting Argos satellites to determine its location.
• Error ranges between 500m and 10km.
• Transmits data.

Question 10

• Geolocator (GLS):

Answer 10

• Measures light levels and accurate time, which can be used to determine geographic location.
• Error range between tens and 100s of kms
• Archival.

Question 11

For smaller animals tracking

Answer 11

• Use of acoustic tags.

Question 12

Tag less tracking:

Answer 12

• Animals need to be captured.
• Tags are too heavy/large in relation to animals.
• Tags can be expensive.
• Track from video.

Question 13

Diel Vertical migration:

Answer 13

• Daily migration for light of phytoplankton.

Question 14

predators to find food:

Answer 14

• Area restricted search.
• Predators search more thoroughly for food in some areas.
• Theory predicts that for a predator, searching for prey with a patchy distribution:
• After encountering prey, should slow down and increase its turning angles to try and remain in the prey patch.

Question 15

Modes of movement:

Answer 15

• Unicellular organisms can be accomplished by changing shape using sliding elements in the cytoskeleton.
• Many organisms use flagella.
• In most cases, forces are generated by contraction forces.

Question 16

Ciliary structure and function:

Answer 16

Cilia and flagella, cylindrical array of 9 filaments within which a microtubule extends into the cilium and a partial microtubule which don’t extend as far.
* Cross-bridges of dynein extend from complete microtubule of one filament to the partial microtubule of the adjacent filament.
* 9+2 arrangement, pair of microtubules down centre.

Question 17

Sliding filament model:

Answer 17

• Strong parallels between this and cilia.
• Powered by ATP
• Dynein like myosin is the ATPase.
• Regulated by calcium ions.

Question 18

Metazoan muscle:

Answer 18

• Muscle contractions are powered by ATP.
• Muscle forces usually act on some type of skeleton.
• In the vertebrates, muscles attach to, and work in conjunction with a bony internal skeleton.
• In hard bodied invertebrates’ muscles attach to exoskeleton.

Question 19

• Muscle contraction:

Answer 19

• Myosin head split ATP, myosin binds to ATP and forms cross bridges.
• Myosin moves forward toward centre of sarcomere.
• Myosin attaches to ATP and crossbridge detach.

Question 20

Hydrostatic skeletons:

Answer 20

• In soft bodied invertebrates, muscle layers act on a hydrostatic skeleton.
• The segmentation in annelids act like boiler stays, allowing the musculature to exert much greater pressure.

Question 21

Metazoan swimming:

Answer 21

• Cilia and flagella, protozoa, macroalgal gametes, larvae and some meiofauna.
• Wave-like undulations, many worms.
• Fluid propulsion, medusoid coelenterates, cephalopods and pectinid bivalves.
• Use of flattened appendages, some decapod crustaceans, fish, cetaceans and pinnepeds

Question 22

locomotion

Answer 22

• Same structure used simultaneously accomplish multiple functions.
• Crustaceans may use rhythmic movement for walking and gas exchange.
• Female brine shrimp combine swimming gas exchange and irrigation of their ovisac.

Question 23

Evolution in locomotion:

Answer 23

• As a result of convergent evolution, species in diverse taxonomic groups may use the same pattern of locomotion

Question 24

Moving through sediment:

Answer 24

• Broadly divided into hard bodied diggers such as crustaceans.
• Echinoids and soft bodied burrowers that include some coelenterates, molluscs, and representatives of all the vermiform taxa.
• Small group of specialised drillers that can bore through soft rock and wood.

Question 25

Reynolds number - Moving through water:

Answer 25

• Organisms whose movements are described by low Reynolds numbers (<10) create laminar flows in their wakes.
• Their movements are mainly affected by viscous drag that retards forwards progress.
• A low Reynolds number organism must continually work to keep moving.
• Organisms with a high number >200000 tend to be larger and faster moving.
• Create turbulent flows in their wakes.
• Turbulence produces low pressure than tends to hold them back, ‘pressure drag’ can be reduced by streamlining.

Question 26

Drag

Answer 26

• Gray’s paradox, power output insufficient for fish to swim at the fast speeds they achieve.
• Evolved adaptations to improve their hydrodynamic efficiencies.
• Dolphin skin delays water flowing over skin and becomes turbulent, reducing drag

Question 27

Drag on sharks:

Answer 27

• Frictional drag is the most important source of drag in fast-swimming fish, such as sharks.
• Caused by the friction created between the skin and the boundary layer.
• can be reduced if the boundary layer maintains a turbulent flow.
• All fast-swimming sharks have sharp-edged riblets on their skin created by the denticles in their skin.
• absorb some turbulence between the denticles, and the sharp edges allow surface vortices to break away easily.

Question 28

Biomechanics of staying still:

Answer 28

• For many sessile species their habitat requires that they resist mechanical forces that dislodge them.
• Shape and ribbing of the base plate of the test increases the adhesion of a protein glue that is coded for the same gene that contributes to clotting agents associated with mammalian erythrocytes.