Vertebrate

Question 1

Extant jawless vertebrates

Answer 1

Agnathans
Hagfish - no vertebral elements
Lampreys - cartilaginous elements around notochord

Question 2

Fully formed vertebrae

Answer 2

Centrum surrounding notochord
-present in jawed vertebrates (Gnathostomes)
—> Exception - many jawed fishes
- functional notochord in adult stage
- centrum with several elements and not a single block of bone

Question 3

All vertebrates

Answer 3

Cranium = derived feature
- bony, cartilaginous, fibrous
- surrounds brain
Prominent head
- complex sensory organs

Question 4

Cranium vs vertebrae?

Answer 4

Craniata vs Vertebrata
Not all vertebrates have vertebrae whereas all vertebrates have craniums
Eg hagfish no vertebral elements