1
Q
Describe the phylum annelida
A
- setae
- centralized nervous system and closed circulatory system
2
Q
What is the next key transition in the Annelids?
A
- true segmentation/metamerism
- they have units separated by septa, filled with organs derived from the mesoderm
3
Q
How do annelids move?
A
they have true coeloms filled with fluid
- hydrostatic skeleton: alternating contraction of longitudinal and circular muscles = peristalsis
4
Q
What are the other defining features of annelids?
A
- setae
- chitinous epidermal muscles
- NOT seen in leeches - parapodia
- paddle like feet
- secondarily lost in most groups
5
Q
Describe the clade errantia
A
- polychaete body plan ; long body hairs
- well developed sense organs/cephalization
- external fertilization / trochophore larvae
6
Q
Describe the Clade Sedentaria
A
- polychaete body plan: food grooves, mucus, cilia and reduced setae and parapodia
- modified heads for feeding
7
Q
Describe the family siboglinidae
A
- beard worms
- tube dwellers; no digestive system/anus - absorption
- symbiotic relationship with the chemo autotrophic bacteria that use H2S
- found near geothermal vents
8
Q
describe the order clitella
A
-synapomorphy: clitellum = reproductive structure
- direct development
- hermaphroditic
- no parapodia, reduced/lost setae
- oligochaete body plan
9
Q
Describe oligochaetes
A
- well developed circulatory, digestive, excretory systems
- simultaneous hermaphrodites
- earthworms
10
Q
Describe subclass Hirudinea
A
- leeches
set # of segments
-> reduced setae and septa
–> powerful pharynx
–> Clitellum only present during reproduction
–> doors ventrally flattened body
Carnivorous and medicinal species
11
Q
Describe class sipuncula
A
- introverted cilaited feeding tentacles
- no setae/septa
- have a trochophore larvae
12
Q
Describe the architecture of the annelids
A
- organs
- triploblast
- true segmentation
- coelomate
- bilateral
