Transcript Animal Movement

Animal Movement
Chapter 30
Locomotion
• Active travel from place to place
• Requires energy expenditures to over come 2
forces
▫ Friction
▫ Gravity
• Importance depends on the environment
Types of Locomotion
• Swimming
▫ Gravity not a problem, but friction is
 Water supports weight, but is dense and presents resistance
▫ Legs as oars, jet-propelled, and undulating side to side or
up and down
▫ Streamlined body shapes aids increased speed
• Locomotion on land
▫ Need to be able to support self and overcome gravity
 Air presents little resistance, but also little support
▫ Energy expenditure to propel forward and keep from
falling down
 Muscles and skeleton more important that streamline shape
Types of Locomotion (cont.)
• Hopping
▫ Tendons in legs store energy when landing, like a
spring for the next jump
 Cost free energy boost
▫ Rest with tail and hind feet on ground
 Costs little energy to maintain
• Walking and running
▫ Overcome friction between foot and ground
▫ Walking: 4 legged – 3 on ground all times; 2 legged –
part of 1 at all times
▫ Running: 4 legged – 2 -3 feet move at once if not all
▫ Momentum stabilizes body position
Types of Locomotion (cont.)
• Crawling
▫ Friction adds considerable resistance because of
increased contact
 Undulate body side to side, inch forward, or peristalsis
• Flying
▫ Wings developed to completely overcome gravity
▫ Shape must alter air current to create lift
 Air pressure underneath is greater
• All based on mircotubule or microfilament
systems. Animals in motion
Skeletons
• 3 main types
▫ Hydrostatic skeletons
▫ Exoskeletons
▫ Endoskeletons
• Necessary for support, protection, and
maintaining form
Hydrostatic Skeleton
• Fluid held under pressure in a closed body
compartment
• Cushions body parts from shock, gives shape,
and support for muscle action
• Earthworms have coelum
• Cnidarians exert pressure on gastrovascular
cavity
• Can’t support terrestrial locomotion which
requires the body to be held off ground
Exoskeletons
• Rigid external skeleton
• Arthropods are protein and
chitin
▫ Thinner at joints to allow
movement
▫ Nonliving, so can’t grow must
be shed
▫ Animal is susceptible to
predation and weak until new
exoskeleton hardens
• Molluscs shells of calcium
carbonate
▫ Mantle secretes shell
▫ Grows by enlarging diameter
Endoskeleton
• Hard or leathery supporting
elements among the soft
tissues
• Sponges with tough protein
fibers
• Echinoderms have under their
skin
• Vertebrates of cartilage or
cartilage and bone
The Evolved Skeleton
• All vertebrates have an axial skeleton
▫ Supports axis or trunk of the body
▫ Skull, vertebrae, and rib cage
 Vertebrae all similar in structure
 Cervical, thoracic, lumbar, and sacral, and coccygeal
• Most have appendicular skeleton
▫ Bones of appendages and anchoring appendages
▫ Pelvic and pectoral girdle with supporting limbs
 Modified versions of same bones in all vertebrates,
but specialized for locomotion
Bones
• Organs composed of moist,
living tissues
• Pink=fibrous connetctive,
forms new bone after fractures
• Blue=cartilage, forms cushionlike surface for joints
• Inside are osteocytes that
secrete bone matrix
• Yellow bone marrow is
stored fat from blood to bone
• Red bone marrow produces
RBC’s
Creating Movement
• Tendons connect muscles to bones
• Muscle action shortens or contracts muscles
• The agonist moves the muscle while the antagonist reverses the
movement
▫ Antagonistic pairs of muscles are found in all animals
Dissecting Muscles
• Muscles consist of bundles of muscle
fibers (cells), oriented parallel to each
other
• Cells are bundles of myofibrils, which
are composed of the contractile proteins
actin (thin) and myosin (thick)
• Proteins form a striped banding pattern
that characterizes skeletal muscles
• Contractile unit of skeletal muscle is the
sarcomere
Contracting Filament Model
• Sarcomere contracts when
thin filaments slide over thick
• Sarcomere shortens, but
length of filaments don’t
change
• Heads of myosin (thick)
filaments bind ATP so they can
bind to actin (thin) filaments
• Head produces power stroke
which moves the actin toward
the center of the sarcomere
when ADP is released
Muscle Fiber Types
Each muscle has a mix of the above types
Slow fibers better designed for endurance
activities
Weight lifting stimulates muscle fibers to
produce additional myofibrils