lecture 19- annelida Flashcards
what is phylum annelida
segmented worms
segmentation
division of at least part of the body into series of relatively similar repeated unitsw
what does segmentation involve
metamerism and tagmatization
metamerism
addition of new segments bw most recently made segment and prosteriorly located growth zone
tagmatization
tagmata that perform particiular functions and are morphologically distinct
did segmentation arise from common ancestor of annelida and arthropoda?
no, it was thought to have been but morphological data show it arose independently
homonomous
body composed of segments that look almost identlical
heteronomous
body composed of clusters of segments morphologically specielized
how many spp phylum annelida
20000
annelida habitat
marine freshwater and terrestrial
three classes of annelida
polychaeta- most marine
oligochaeta- earthworm and freshwater
hirudinea- leeches
what does phylum clitellata share
clitellum
what is the development of annelida
protostome like, blastospore becomes mouth
spiral cleavage
schizocoelous development of coelom
what type of larva do marine annelida have?
trochophore
what type of gut annelida
complete, with terminal anus
what does each segment have
eucoelomic cavity
what is gut supported by
mesentaries
what type of circ
closed circ system with pumping hearts
what does blood contain annelida
respiratory pigments
what tpye of nervous system shit annelida
-dorsal anterior ganglion (BRAIN)
-circumesophageal nerve connectives
-1-2 ventral nerve cords
do annelids have metanephridial system?
most do
what is metanephridial system
ultrafiltration occurs in structure separate from resoption and transport
what lies in segment anterior to nephridial tubule/ duct w nephridiopore
flame cell or open funnel like nephostome
Flame cell
Open Funnel like nephrostome
What are the two consequences of metamerism in annelids
Functional: allow control of shape through muscular actuon
Developmental: segments develop independently
where is mouth annelida
periostomium
where is anus annelida
pygidium
what lies infront of periostomium
protostomium
where are new segments added
anterior to pygidium
what is along body
chaetae, that are chitenous bristles
what is outer layer
non living, noncilliated cuticle
