Cephalochordata and Urochordata

Question 1

Ascidiacea arrangements

Answer 1

• individual
• social- all attached to same base
• colonial- all in same tunic
• compound- share excurrent siphon

Question 2

Thaliacea

Answer 2

salps

• pelagic
• sexual and asexual lifecycles
• excurrent siphon on posterior

Question 3

Larvacea

Answer 3

• tadpole-like

- build ‘houses’ around themselves

Question 4

Ascidiacea (sea squirts) features (6)

Answer 4

• sessile
• can filter more than 100 liters a day
• gill slits
• tubular heart, can pump in both directions
• hermaphroditic
• tadpole larvae

Question 5

Urochordata (Tunicata) features (6)

Answer 5

• incurrent and excurrent siphon
• dorsal hollow nerve chord in larvae
• notochord in larvae
• gill slits in larvae
• tunics
• filter feeders

Question 6

Ascidiacea filtering

Answer 6

• cilia on gill slits create currents
• tentacles prevent siphon clogging
• mucus secreted and moves down mucus train into mouth