ch 25: hemichordata & chordata Flashcards
1
Q
what do chordate feats is hemichordata missing
A
- notochord
- post anal tail
2
Q
4 hemichordates feats
A
- dorsal hollow nerve cord
- pharyngeal slits
- proboscis
- collar
3
Q
pterobranchs feats (4)
A
- small colonial filter feeders/zooids
- resemble bryozoans
- live in tubes
- have unciliated tentacles on arms
4
Q
graptolites
A
fossils of pterobranchs used to date Paleozoic rocks
5
Q
enteropneusts
A
acorn worms
6
Q
2 functs of acorn worm proboscis
A
- burrowing in soft mud
- eat mud/collect food
7
Q
3 feats of enteropneusts
A
- no real brain or specialized sense organs
- open fert
- w is forced out pharyngeal slits
8
Q
notochord
A
- formed from dorsal mesoderm
- forms discs btwn backbone
9
Q
subphylum urochordata feats (2)
A
- most sedentary sea squirts
- a few are pelagic or planktonic
10
Q
tunic =
A
outer coating strengthened by cellulose-like carb called tunicin
11
Q
inside sea squirt tunic (3)
A
- modified pharynx
- endostyle secretes sheets of mucus
- branches of air syst
12
Q
sea squirt nerve ganglion (2)
A
- controls squirting and cilial beating
- sensory cells detect toxins and sedi
13
Q
can sea squirts be colonial
A
yes
14
Q
sea squirt repro (2)
A
- asexual repro via budding
- sexually - hermaphrodites (open fert?)
15
Q
sea squirt larvae (3)
A
- tadpole swims but does not feed
- seeks settling spot
- better sensory sys then adults
