lecture 8 animal Flashcards
hardened support structures can be ..
external, internal, or absent
hydrostatic skeleton
fluid held under pressure in a closed body compartment – pressure around fluid is what makes animal feel hard
examples of hydrostatic animals
worms, jellyfish, sea anemone
endoskeleton
hardened internal skeleton
examples of endoskeleton animals
sponges, humans,
exoskeleton
hardened external skeleton
examples of exoskeleton animals
arthropod cuticles – shrimp, crabs..
locomotion with hydrostatic skeleton
peristaltic crawling of earthworms
what types of muscles are earthworms composed of to allow crawling motion
longitudinal muscles and circular muscles – also have bristles
what do the segments of worm look like when longitudinal muscles are contracted
short and fat
what do segments of worm look like when circular muscles are contracted
long skinny
run down of how worm moves
head extends out – circular muscle contracting – bristles will grasp ground – bringing body to head longitudinal are contracting squeezing body forward
endoskeletons and exoskeletons generate movement using what
muscles attached to the hard parts of a skeleton
where is the tricep and bicep connected
antagonistic muscles generate..
opposite movements across a joint
- when one contracts the other relaxes (bicep pulls arm bone towards it when contracts – when relaxed and tricep contracts, brings are out)
vertebrate skeletal muscle is an excellent example of
hierarchial organization in biological structures
hierarchial organization of muscle
skeletal muscle – muscle fibres (each a multinucleated muscle cell) – myofibrils – thin (actin) and thick (myosin) filaments
sarcomere
functional unit of contraction – Z lines separate each sarcomere – sarcomeres shorten during muscle contraction
myofibrils are composed of
thin actin and thick myosic filaments
thin filament
actin – two chains of actin molecules – contain myosin binding sites
thick filament
multiple myosin molecules with their head exposed for binding – motor protein can generate movement with ATP
where are the thin and thick filaments attached on the sarcomere
tail ends of actin are attached to z line and tail ends on myosin are attached to M line
skeletal muscle is an example of what type of muscle
striated muscle
what is a striated muslce –
bunch of lines – linear
what parts of the sarcomere change during contraction and what paerts do not
sarcomere changes length but thin ad thick filaments stay same size they just overlap and slide past each other
muscle contraction cycle step `1
we have our myosin binding sites – ATP is attached to the myosin head which is at a low configuration meaning its head is not at the right shape/position for binding with the actin myosin binding site
muscle contraction cycle step 2
through hhydrolysis ATP will be converted to ADP and inorganic phosphate which will make the myosin head have a high energy configuration – this means the head is now at a position where it can bind to the myosin binding sites
muscle contraction cycle step 3
this cross bridge is formed when the myosin head attaches to the actin filament
muscle contraction cycle step 4
the loss of ADP and inorganic phosphate will force the myosin head to retrieve back to its original bent position which forces and pulls the actin filament towards the center of the sarcomere – this is what causes the contraction
– when ATP is present again cycle will repeat
how does the muscle know when to contract
– the contraction is initiated by motor neurons – specifically results in the increase of free calcium ions in the myofibrils of muscle cells therough neurotransmitter exchange
why do we need calcium for muscle contraction in addition to ATP
the actin filament is not completelty available for myosin heads to bind
– it is wrapped in regtulatory proteins tropomyosin and troponin which block the actin’s myosin vbinding sites.
– Ca2+ will bind to the troponin which will unravel the proteins and expose the binding sites to allow binding
what is locomotion
active travel from place to place
to move, an animal must expend ..
energy to overcome gravity and friction
what determines the the force animals have to overcome
the enviornment – whatever force is dfominant that opposes locomotion has to be overcome
land and air dominating force
gravity
water dominating force
friction
natural selection favours..
adaptations tha treduce energy costs of locomotion
adaptations are usually what
anatomical (anatomy based)
example of anatomical adaptation
fusiform body shape, springy tendons
fusiform body shape adaptation
fish – tapered at both ends allowing for faster swimming
springy tendons shape adaptation
animals that need to jump – springs reduce energy cxost
adaptations can also be
behavioural
examples of behavioural adaptations
passive descent in diving animals – positions themselves so gravity makes them go down instead of them having to use eenrgy to dive,.
animals that locomote on land require..
powerful muscles and strong skeletal support to propel themselves and remain upright
maintaining ehat is essential for land animals
balance
when walking, how many legs do bipedal animals keep on ground
one
when walking how many legs to multi-legged animals keep on ground
three
when running or hopping..
all legs can leave the ground because momentum keeps body upright
adaptations can reduce..
energy expenditure
reducing energy expenditure example (kangaroo)
when the tendons stretch as the animals land, they store enrgy in elastic fibres which is released to help the next jump
wings of flying animals must generate enpoigh what to overcome gracities downward force
lift – which can be achieved by the wing shape itself
what do flying animals tend to have that help with locomotion in air
birds – no uninary bladder – no teeth – hollow air filled bones - all light weight so they have less weight to carry – also fusiform body
most aquatic animals are reasonably..
buoyant – naturally float in water due to extra flubber
– fusiform body is adapted to reduce friction/drag
