2 - Terrestrial locomotion Flashcards
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The need for locomotion
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
Locomotion def
The coordinated movement btwn support structures, joints, muscles and other tissues
Endoskeleton derived from
Derived from MESODERM
Exoskeleton derived from
ECTODERM
Muscle pair names
- Flexors & extensors
- Adductors & abductors (which open and close a clam shell)
Advantages of endoskeleton
- allow to grow large
- better defense
- more precise and controlled movement
Fundamental properties of Hydrostatic skeletons
- liquid incompressibility
- ability to assume any shape/ fill a container
Hydrostatic skeleton def
- 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
What controls the loss and intake of fluid?
Sphincter muscles
Pseudopodia def
False leg - forms in any direction to lead the organism in that way (amoeboid mvmnt)
Cilia def
Tiny hair-like structures which act as oars and beat to propel the organism forward - requires immersion (ciliary mvment)
Flagella def
Whip like appendages protruding from body.
Oscillates to propel forward - requires immersion (flagellar mvmnt)
Locomotion organs
- Cilia
- Flagella
- Pseudopodia
- Hydrostatic propulsion
- Limb mvmnt
Immersion def
(in water)
Hydrostatic propulsion def
Uses a series of muscles and fluid filled chamber with CONTROLLED opening/closing to propel body forward.
Limb mvmnt def
Uses a series of muscles and either an exoskeleton OR hydrostatic skeleton
Limb types
- legs
- tube feet
- wings
Locomotion modes
- Change locomotion throughout lifetime
- More than one form of locomotion
- Same structure for multiple functions (crustacean uses rhythmic mvmnt of thoracis appendages for walking and gas exchange)
- Same function can be done by different structures (jumping - legs or special structures such as furcula in springtails which flicks)
- Convergent evolution = diverse taxonomic groups may use same locomotion (Undulatory - nematode worms and marine worms, despite their distant)
Terrestrial locomotion
- Crawling
- Walking, running, jumping
Aquatic locomotion
- Rowing
- Undulatory mvmnts
- Specialized fins
- Jet propulsion
Aerial locomotion
- Flight
- Gliding
- Ballooning
Crawling
- 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)
Principles of peristaltic movements
- incompressibility of liquids
- ability to fill or take any shape
Types of peristalsis
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)