Annelida Flashcards
What form did the ancestral Annelida larva come in?
Trochophore
What size was the adult forms and 3 aspects of the bodies of ancestral Annelida?
Adults - small
Segments with pair of coelomic sac
chaetae (chitin bristles)/setae (stiff bristles)
no parapodia (muscular bristle appendages used for movement)
Where were ancestral Annelida found?
Benthic (lowest levels of water) burrowing
What symmetry is Annelida?
Bilateral
What coelom and how does it form in Annelida?
Eucoelomate - formed by schizocoely = mesoderm separatesto form coelom
Are Annelida segmented? Why?
Yes - arises form teloblastic growth (large cell divides into many smaller cells and specialize)
What is the digestive tract and circulatory system of an Annelida?
Complete digestive
Closed circulatory
Explain the nervous system of an Annelida (2)
Has dorsal cerebral ganglion (upper or backside, # of nerve cells) And ventral (underside) ganglionated nerve chord(s)
Explain the head region of an Annelida (2)
Presegmental prostomium (1st body segment, anterior end, doesn’t include mount) and peristomium (2nd body segment, anterior end, contains mouth)
How do Annelida reproduce?
Gonochoristic or hermaphroditic
What are the 2 class of Annelida?
1- Polychaeta
2- Clitellata
What 2 things does the class Polychaeta have?
1- parapodia (muscular bristled appendages ancestors don’t have) - for gass exchange and locomotion
2- acicula (support rods)
What are the 2 subclasses of the class Polychaeta? Differences (found and parapodia)
1- Errantia - mobile/surface dwellers use parapodia as oars
2- Sedentaria - burrows parapodia reduced/modified/lost
What are the 2 families of the class Polychaeta?
1- Nereidae
2- Arenicola
What is an example of the family Nereidae of the class Polychaeta? Live? Important?
Nereis Virens
Live in tubes or burrows
Economically important bait worm
What is an example of the family Arenicola of the class Polychaeta? Live?
Arenicola = lugworms
Live in burrows
Explain the class Clitellata
Reduced # of segments with reproductive organs and clitellum (raised band around body with reproductive segments)
What are the 2 subclasses of the class Clitellata?
1- Oligochaeta
2- Hirudinea
How does the subclass Oligochaeta differ from the class Polychaeta?
Have setae but less than Polychaeta - used for locomotion and burrowing to prevent slipping
What is the family under the subclass Oligochaeta of the class Clitellata?
Lumbricidae
What is an example of the family Lumbricidae of the subclass Oligochaeta?
Lumbricus terrestris = earthworm
How does Lumbricus terrestris (earthworms) of the family Lumbricidae move?
Peristalsis (Constriction and relaxation of the muscles = wave like motion) with setae used for anchorage
What are the subclass Hirudinea?
Leeches
What 2 things does the subclass Hirudinea of the class Oligochaeta lack?
No parapodia (appendages) no setae (bristles)
