hemi-/chordata

Question 1

hemichordata

Answer 1

marine, benthic, tripartite body wth eucoelom. one or more gills. solitary or colonial .deposit or suspension feeders. no brain, eyes. have dorsal + ventral cords. open ciruclatory system.
seperate sex. both sexual + asexual

Question 2

class enteropneusta

Answer 2

solitary sediment-dwelling.
- prosome. mesosome, metasome.
each region has it’s own eucoelomic cavities. 5 in total.
branchial chamber for gill slits.
proboscis covered with cilia and mucus. most deposit-feed. asexually or sexually with broadcast sperm. blastopore closes.

Question 3

class pterobranchia

Answer 3

tube-dwelling. colonial
prosome - cephalic shield. mesosome: collar. look like lophophore cilia.
metasome: short globular trunk + stalk
1/2 eucoelomic cavities.
stalk connect to stalk of next zooid or central disk.

Question 4

pterobranch feeding

Answer 4

suspension - cilia create current

particle gets stuck on mucus + moved to mouth. u-shaped gut.

Question 5

pterobranch repro

Answer 5

asexual budding. colonies both m +f. sexual repro - external fertilization, brooding.

Question 6

3 lineages of chordata

Answer 6

vertebrata
cephalochordata
urochordata

Question 7

4 morphological features. 3 are synapomorphies

Answer 7

notochord (unique)
dorsal, hollow nerve cord: unique
pharyngeal slits/clefts
muscular, post-anal tail: unique

Question 8

notocord?

Answer 8

flexible rod dorsally between digestive tube + nerve cord. adds stiff but not rigid support.

Question 9

features in vertebrata and cephalochordata

Answer 9

segmentally arranged muscle blocks = mytomes.

Question 10

features in cephalochordata + urochordata

Answer 10

endostyle, ciliated ventral groove into pharynx

Question 11

cephalochordata

Answer 11

lancelets. marine. benthic. notocord extends anteriorly beyond the nerve cord.
poor swimmers, mostly sedentary suspension feeders. ciliated pharynx sucks in water + food.
closed circulatory, no heart

Question 12

urochordata

Answer 12

marine. body covered by tunic. notochord in larva only.

open circulatory. no gas exchange/exretory.

Question 13

urochordata class ascidiacea

Answer 13

solitary or colonial. filter feeders. active larvae, no muscle segmentation into blocks
large pharynx, endostyle.
colonial share single tunic & connect by tissue.
hermaphroditic.

Question 14

urochordata - class larvacea

Answer 14

tad-pole like. pelagic. adults retain notochord + dorsal nerve cord