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Chapter 11- Phylum Annelida (segmented words) - Coggle Diagram
Chapter 11- Phylum Annelida
(segmented words)
Basic stuff
triploblastic coelomate, formed from schizocely
bilateral symmetry
ventral nerve cord, closed CS. no lungs, diffusion through body
Synapomorphies
metamerism (segmentation)
. body is composed of
metemeres and seperated by septa.
chaetae (setae)
- bristle-like structures
made of chitin
on surface. with protractor and retractor muscles
2 Major classes: Polychaeta & Clitellata.
2
subclasses of clitellata: oligochaeta & hirudinea
(they all have clitellum aka collars containing mucus glands)
Class Polychaeta:
mostly marine and have eyes. highly cephalized. many have
statocysts
for balance.
parapodia. notopodium (dorsal) & neuropodium (ventral)
Reproduction
: dioecious. gonads are only temporary. gametes stored in coelom and use external fertilization.
Paraphyletic
. Errantia (free-swimming or crawling) & Sedentaria (tube/burrow dwelling)
Errantia
are fireworms and scaleworms. carnivorous and have venom.
Sedentaria
are tube worms. live in u shaped tubes underground and pump water.
Class Clitellata
:
Subclass Oligochaeta: earthworms. four pairs of setae per segment. 5 accessory hearts.
each segment has a pair of
nephridia.
nephrostomes- draw in waste and exit through nephridiopores.
Reproduction: monoecious. they hold onto each other through their clitellums. but can also be asexual.
Subclass Hirudinea: leeches. posterior and anterior suckers. 75% feed on vertebrae blood.
Hirudo medicinalis — antiseptic
bite. they also secrete anticoagulate and vasodilators to aid feeding.
solely sexual, mate same way as earthworms.