2 - Terrestrial locomotion

Question 1

The need for locomotion

Answer 1

Life progressed from uni-cellular to multi-cellular – there was a need to (a) support and (b) move to overcome gravity and/or water pressure/currents/wind
- defense
- escape
-search for food
reproduce
- avoid overcrowding

Question 2

Locomotion def

Answer 2

The coordinated movement btwn support structures, joints, muscles and other tissues

Question 3

Endoskeleton derived from

Answer 3

Derived from MESODERM

Question 4

Exoskeleton derived from

Answer 4

ECTODERM

Question 5

Muscle pair names

Answer 5

• Flexors & extensors
• Adductors & abductors (which open and close a clam shell)

Question 6

Advantages of endoskeleton

Answer 6

• allow to grow large
• better defense
• more precise and controlled movement

Question 7

Fundamental properties of Hydrostatic skeletons

Answer 7

1. liquid incompressibility
2. ability to assume any shape/ fill a container

Question 8

Hydrostatic skeleton def

Answer 8

• Enclosure of a fluid-filled chamber (COELOM) with sets of opposing muscles
• a system in which muscles contract in one part of the body and force fluid to another region of the coelom where muscles are relaxed
• changes the shape of the body or extends it in one direction
• Sphincter muscles around openings to control the loss/intake of fluid

Question 9

What controls the loss and intake of fluid?

Answer 9

Sphincter muscles

Question 10

Pseudopodia def

Answer 10

False leg - forms in any direction to lead the organism in that way (amoeboid mvmnt)

Question 11

Cilia def

Answer 11

Tiny hair-like structures which act as oars and beat to propel the organism forward - requires immersion (ciliary mvment)

Question 12

Flagella def

Answer 12

Whip like appendages protruding from body.
Oscillates to propel forward - requires immersion (flagellar mvmnt)

Question 13

Locomotion organs

Answer 13

1. Cilia
2. Flagella
3. Pseudopodia
4. Hydrostatic propulsion
5. Limb mvmnt

Question 14

Immersion def

Answer 14

(in water)

Question 15

Hydrostatic propulsion def

Answer 15

Uses a series of muscles and fluid filled chamber with CONTROLLED opening/closing to propel body forward.

Question 16

Limb mvmnt def

Answer 16

Uses a series of muscles and either an exoskeleton OR hydrostatic skeleton

Question 17

Limb types

Answer 17

• legs
• tube feet
• wings

Question 18

Locomotion modes

Answer 18

1. Change locomotion throughout lifetime
2. More than one form of locomotion
3. Same structure for multiple functions (crustacean uses rhythmic mvmnt of thoracis appendages for walking and gas exchange)
4. Same function can be done by different structures (jumping - legs or special structures such as furcula in springtails which flicks)
5. Convergent evolution = diverse taxonomic groups may use same locomotion (Undulatory - nematode worms and marine worms, despite their distant)

Question 19

Terrestrial locomotion

Answer 19

1. Crawling
2. Walking, running, jumping

Question 20

Aquatic locomotion

Answer 20

1. Rowing
2. Undulatory mvmnts
3. Specialized fins
4. Jet propulsion

Question 21

Aerial locomotion

Answer 21

1. Flight
2. Gliding
3. Ballooning

Question 22

Crawling

Answer 22

• soft bodied
• fluid filled cavities
• two-anchor method - body extended anteriorly by contraction of CIRCULOR muscles on fluid cavity (hydrostat) (CATERPILLARS)
• one anchor method - extends foot thru substrate, dilates the end of foot to anchor the tip of foot & then draws the body thru substrate using CONTRACTILR muscles of foot (Bivalve)
• Peristatic mvmnt - muscle contraction and relation creates a versatile mvmnt system based on principles (annelids)

Question 23

Principles of peristaltic movements

Answer 23

• incompressibility of liquids
• ability to fill or take any shape

Question 24

Types of peristalsis

Answer 24

Retrograde - changes in elongation and shortening occur in opposite direction to mvmnt (Segmented)
Direct - changes in segment volume during elongation and shortening occur in direction of mvmnt (Unsegmented)

Question 25

Walking, jumping and running def

Answer 25

• Having legs or parapodia (or un-joined protrusions)
• involves coordinate mvmnt of uniramous appendages in different planes

Question 26

Burrowing invertebrates

Answer 26

• short legs
• slow and powerful gait

Question 27

Gait def

Answer 27

Manner of mvmnt or pattern of mvmnt of limbs

Question 28

Longer limbs =

Answer 28

Reduce force, but increase speed (Fast running insects)

Question 29

Subphylum Myriapoda

Answer 29

1 - Millipedes (Diplopoda) - 2 legs per segment, slow but powerful GAIT
2. Centipedes (Chilopoda) - one longer leg per segment, fast but not as powerful

Question 30

Uniramous def

Answer 30

Single series of segments

Question 31

Leg interference

Answer 31

Can slow down organism, make it prey

Question 32

How is leg interference avoided?

Answer 32

By the placement of the tips of ADJACENT legs at different distances from the body

Question 33

How do fast running insects move?

Answer 33

Have legs of slightly different lengths and move in an alternating tripod sequence

Question 34

How do insects walk on water?

Answer 34

By balancing the pull of gravity on their extremely light weight with the physical properties of water (buoyancy and surface tension)
- These insects have waxes over exoskeleton to repel water, and microscopic hairs that trap air bubbles, allowing them to float.
- Water surface bends under each leg and the depression pushes the animal upwards (Water striders, Coleopterans and springtails)
- Have high SA:V ratio

Question 35

Jumping in springtails

Answer 35

Associated with furcula (forked appendage at end of springtail)

Question 36

How do the sensory and mechanical feedback systems play a role in locomotion?

Answer 36

The CNS generates motor commands that activate the musculoskeletal system of the insect, which then acts on the external environment
Sensory feedback = guidance and equilibrium and rapid feedback from mechano-sensors
Viscoelastic preflexes act to resist perturbations (muscles = motors, brakes or springs).