Lab 2 (Shark and vertebrae)

Question 1

SHARK
placoid scales

Answer 1

have posterior orientation to reduce turbulence along the body surface, remnants of the ancestral bony armour

Question 2

SHARK
rostrum

Answer 2

tip of nose - used to limit water resistence

Question 3

SHARK
heterocercal caudal fin

Answer 3

produce thrust that results in forward movement

Question 4

SHARK
ampullae of lorenzini

Answer 4

dorsal and ventral side of rostrum; act as electroreceptors

Question 5

SHARK
gill slits

Answer 5

5 locaed laterally and anterior to pectoral fin; respiratory water exits through these when not feeding)

Question 6

SHARK
precerebral cavity

Answer 6

on dorsal apsect of chondrochranium; holds jelly like material near rostrum

Question 7

SHARK
foramen magnum

Answer 7

spinal chord passes through this

Question 8

SHARK
occipital condyles

Answer 8

articulates with first trunk vertebra

Question 9

SHARK
optic foramen

Answer 9

optic nerve passes through this

Question 10

SHARK
palatoquadrate

Answer 10

thought to be derived from the paired epibranchial elements of arch

Question 11

SHARK
meckel’s/mandibular cartilage

Answer 11

lower jaw - splanchnocranium

Question 12

SHARK
hyoidmandibular cartilage

Answer 12

splanchnocranium, hyoid arch

Question 13

SHARK
basihyal cartilage

Answer 13

splanchnocranium, hyoid arch

Question 14

SHARK
neural arch

Answer 14

extends dorsally and cradles spinal cord

Question 15

SHARK
neural spine

Answer 15

vertebral column, terminal of vertebral canal

Question 16

SHARK
dorsal intercalary plates

Answer 16

triangular plates that complete a continuous roof over the spinal cord

Question 17

SHARK
basapophysis

Answer 17

homologous to basal portions of hemal arches

Question 18

SHARK
ribs

Answer 18

cartilginous, articulate with basapophysis

Question 19

SHARK
ventral intercalary plates

Answer 19

very small triangular structures that occur between the basapophysis

Question 20

SHARK
ceratotrichea

Answer 20

offers neural support for the fin that extends and stiffins into fin web

Question 21

SHARK
basal pterygiophores

Answer 21

3 parts that articulate with scapular cartilages; support fins proximally

Question 22

SHARK
radial pterygiophores

Answer 22

median fins - radiating from the basal cartilages; forms major support of the fin

Question 23

SHARK
puboischiadic bar

Answer 23

makes up the pelvic girdle

Question 24

iliac process

Answer 24

projects from anterior end of puboischiadic bar