Lecture 27: Chordates

Question 1

Phylum Chordata traits?

Answer 1

Bilateral symmetry
Deuterostomia
Coelom
Segmented

Question 2

Four synapomorphies?

Answer 2

Notochord: For support
Dorsal holllow nerve cord: spinal cord
Pharyngeal slits
Post anal tail

Question 3

Cephalochordata (Lancelets)

Answer 3

All marine
Adult has chordate states
Segmented
Suspension feeders

Question 4

Vertebrate brain evolved from?

Answer 4

Lancelet’s simple nerve cord

Question 5

Urochordata (Tunicates)

Answer 5

All marine
Adults dont look like chordates
Use pharyngeal basket to feed

Question 6

Notochord is?

Answer 6

Homologous

Question 7

Pikaia?

Answer 7

Early chordate

So…no head?

Question 8

Haikouella?

Answer 8

eyes and brain, no skull

Question 9

Myllokunmingia

Answer 9

Skull but no vert

Question 10

Subphylum Vertebrata?

Answer 10

Vertebral column=backbone
Replaces notochord function
Gene dup.: two or more hox gene clusters
Inverts have 1

Question 11

Class myxini

Answer 11

Hagfish
All marine
Cranium made of cartilage

Question 12

Class petromyzontida?

Answer 12

Lamprey 
marine and freshwater
eyes with lenses but no jaws
Skeleton is cartilage
Notochord surrounded by cartilage tube
partial vert column