Chapter 9- appendicular skeleton Flashcards
paired fins/limbs and girdles attaching appendages to axial skeleton
appendicular skeleton
two girdles
pectoral and pelvic
membranous or webbed processes reinforced by internal fin rays
fins
elasmobranch rays are made of
ceratotrichia which are keratinized rods
bony fish rays are made of
lepidotrichia which are ossified/cartilage rays
proximal, mid, and distal fin support
basal pterygiophores
radial pterygiophores
rays
what are the two sets of paired fins
pectoral and pelvic fins
a limb - muscular appendage with well defined joints and distal digits
chiridium
morphological term for upper arm or thigh
stylopodium
morphological term for forearm or shank
zeugopodium
morphological term for manus or pes
autopodium
pectoral articulation
glenoid fossa
pelvic articulation
acetabulum
two big roles for the fins
stabilization in the water
role in locomotion
three motions of fins
roll, pitch, yaw
two theories of fin origin
gill arch theory
fin-fold theory
fins and girdles derived from gill arches
gill arch theory
whats so hard to explain about the gill arch theory
it doesn’t account for the pectoral fins
pelvic and pectoral fin sets derived from two continuous ventrolateral folds of ancestral fish
fin-fold theory
what is interesting about limb development
asymmetric development
early tetrapods only have made of three parts called
one bone in the pelvic girdle
illium, ischium, pubis
bones of the digits
metacarpals/metatarsals and phalanges
bones of wrist/ankle
carpals/tarsals
primitive tetrapods have this many digits and this many digits became established as the common plan
more than 5
5
four reasons to move from aquatic to terrestrial life
fishes able to move to move from water to water over land
avoid predation by moving to shallows or onto beaches
breath air where there is more oxygen
there is abundant food sources on land
what is the difference between early tetrapod/ amphibian/reptile movement and eutherian mammal movement
lateral limbs vs limbs drawn under the body
pendulous limb vs overarm swing
what is the advantage of having limbs under the body
allows for better locomotion with the limbs only moving in one plane
what is another word for running
cursorial
what was the structural change in the limb design when limbs are drawn under the body
forelimbs are now under the scapula and have a greater role in weight bearing
there is a reduction of pectoral girdle elements
in mammals how does the flexion of the vertebral column change
shift from lateral flexion to vertical flexion
three hypotheses on the evolution of bird flight
bipedal tree dwelling ancestor
feathered limbs as insect catchers
feathered limbs to support running
