Module 5 Flashcards
1
Q
chordal center
A
sheath becomes cartilage
2
Q
terapod development
A
- cells in primary sclerotome split
- migrate to notochord forming secondary sclerotomes
- perichordan rings forms and eventually connect to form perichordal tube
- cells grow upwards - neural arches, spines
- chondrification then ossification
- intervertebral disks differentiate
- ## vertebrae from 2 sclerotomes
3
Q
why learn about fishes?
A
- human vertebral malformations
- no suitable tetrapod model
- fishes have many similar malformationms
- we know the genetics
- we can eliminate gravity and the appendicular skeleton from the equation
4
Q
The start of neural arches and notochord.
A
hagfish - nothing
lamprey - small vartilages anteriorly
other agnathans - probably same
5
Q
primitive gnathosthome column
A
- placoderms, acnathodians, early chondrichthyes, ascipenseriforms, most sactopterygian fishes
6
Q
phylogenetic patterns
A
- modern chondrichthyes, neopterygii, bichirs - fully formed centra, aphicoelous except gar (opisthocoeulous).
- lateral flexure could cause column to buckle
- centra - prevent compression
- invertebral ligament - return stiffness
7
Q
heterocercal
A
primitive
8
Q
homocercal
A
teleosts
9
Q
diphycercal
A
lungfish, coelacanths, bichirs
10
Q
shark as heterocercal
A
provides lieft.
11
Q
homocercal
A
pushes straight forward.
12
Q
diphycercal examples
A
- australian lungish
- coelocanthh
- bichir
13
Q
weberian apparatus
A
- modifications of anterior 4-5 vert.
- in otphysi
14
Q
phylogenetic patte4rns
A
- osteopimorphs
- intercentrum dominates -
15
Q
tiktaalik
A
- adds atlas
- neck - first neck to vertebrae.
- dorsoventral motion (up and down motion).
