Annelida Flashcards
Annelida are _ worms
Segmented
Annelids are found in ___,___, and ___
marine, freshwater, moist terrestrial habitats
Annelids exhibit ___ segmentation or ___
True, metamerism
The segments ___ contain repeated ___
external and internal morphological features
___ work together for the whole organism
Segments
In most Annelid species except ___ each segment has chitinous extensions called ___/___ that aid in movement
leeches, chaetate/setae
Short setae ___, long setae ___
anchor segments, aid in swimming in aquatic forms
Typical annelids have a ___, ___, and a ___ called the ___
2 part head, segmented boy, terminal portion, pygmidium
Parts of the head: ___ and ___
Prostomium, Peristomium
The pygmidium contains the ___
anus
The ___ and ___ are not considered segments
Head, pygmidium
Older segments are found in the ___
anterior end
All annelids have a ___
true coelom
The true coelom in annelids form via ___
schizocoely
Coelom is composed of ___ in each segment
paired compartments
Partitions in annelids are called ___
Septa
Septa prevent ___
movement of fluids between segments
___ surrounding the coelom is lined with ___ and ___ muscles
Body wall, circular, longitudinal
Annelids move by ___
producing alternating waves of contraction
Most annelids except ___ have a fluid filled coelom that serves as ___
Leeches, hydrostatic skeleton
Annelids have a ___ digestive system with ___
complete, specialized organs
A pair of ___ facilitate excretion
nephridia
Gas exchange is either through ___, ___, or ___
skin, gills, parapodia
Annelids have a ___ circulatory system with ___ (“hearts”) for ___
closed, aortic arches, pumping blood
Annelid nervous system is well developed with ___ and a ___ around the pharynx
2 ventral nerve cords, nerve ring
Annelid nervous system have a ___ and ___
double ventral nerve cord, paired ganglia
Annelida brains is made up of ___
dorsal ganglia
Annelids are either ___ or ___
monoecious, dioecious
Monoecious annelids have ___ gonads
permanent
Dioecious annelids have ___ gonads
temporary
Annelid asexual reproduction occurs via ___ and ___
fission, fragmentation
Annelids are capable of complete ___
regeneration
3 historical classes of Annelids
Polychaeta, Oligochaeta, Hirudinea
Polychaeta and Oligochaeta are ___
paraphyletic
___ is used to refer to annelids with many setae
Polychaete
2 main groups containing most annelids
Sedentaria, Errantia
(Errant polychaetas) are mostly ___
Marine
(Errant polychaetes) have multiple ___ per segment
Setae
(Errant Polychaetes) segments have paired, fleshy appendages called ___
parapodia
(Errant polychaetes) Parapdoia are the primary ___
Respiratory organs
(Errant polychaetes) are usually ___ or ___
predators, scavengers
(Errant polychaetes) have highly developed ___
Sensory organs
(Errant polychaetes) eyes range from ___ to ___
simple eyespots, well developed eyes
(Errant polychaetes) have ___ sex organs
No permanent
(Errant polychaetes) Fertilization is ___
external
(Errantia polychaetes) No permanent ___
sex organs
(Errantian polychaetes) ___ are temporary swellings of the ___ and ___ are shed into the ___
Gonads, peritoneum, gametes, coelom
(Errantian polychaetes) Fertilization is ___
external
(Sedentaria) Contains ___ and ___ that live in tubes or burrows
Sedentary polychaetes, oligochaetes
(Sedentaria) Body plan similar to ___ but with ___ around the head for feeding
Errantia, tentacles
(Sedentaria) Some also use tentacles for ___
respiration
Parapodia are ___ and are sometimes used to ___ the worm
small, anchor
(Clade Clitellata)
Earthworms and relatives (Ologochaeta)
(Clade Clitellata) Have ___, ___, or ___ chaetae
fewer, reduced, no
(Clade Clitellata) Contain a ___
clitellum
(Clade Clitellata) Clitellum
Ring structure in the skin that secretes mucus for reproduction
(Clade Clitellata) The clitellum is always visible in ___, but is only visible in ___ during mating season
mature oligochaetes, leeches
(Clade Clitellata) All are ___
monoecious
(Clade Clitellata) Development is ___
Direct
(Oligochaetes)
Paraphyletic
(Oligochaetes) Most are ___ or ___ with a few ___
Terrestrial, freshwater, marine, and brackish forms
(Oligochaetes) ___ are less numerous than in polychaetes
Setae
(Oligochaetes) ___ have longer setae
Aquatic worms
(Oligochaetes) Typical annelid body plan other than ___ and ___ systems
Digestive, nervous
(Oligochaetes) Lack ___, ___ extend directly from the body wall
Parapodia, setae
