ANNELIDA Flashcards
Where are they found?
Terrestrial, marine, and freshwater
Segmented or unsegmented?
Segmented (repeating segments)
triploblastic or diploblastic?
triploblastic
acoelomate, no coelom, or true coelomate
true coelomate
complete or incomplete gut?
complete gut
what type of circulatory system?
closed circulatory system
what type of larva?
trochophore
protostome or deuterostome?
protostome
where is the prostomium?
head
where is the peristomium?
mouth
where is the pygidium?
anus
define homonomous
segments are all the same
define heteronomous
segments are different
Parapodia with bundles of
_____?
setae
what type of muscles?
Longitudinal and circular
muscles along body
Oblique muscles to
parapodia
How do annelids move (Free-swimming and crawling species)
- Circular muscles maintain body form.
- Longitudinal muscles in bands within each segment.
Alternately contract and relax for undulation. - Parapodia push off substratum during power stroke and
retract during recovery stroke.
How do annelids move (Burrowing species)
- Circular muscles more developed for peristaltic motion.
- Septa perforated so contracting a group of segments
causes others to extend.
explain the nervous system
Cerebral ganglia specialized with different parts that innervate different parts of the worm
explain their sense organs
Well developed sense organs
How do they feed?
Direct deposit feeders
Hunters with large jaws
Selective feeders with tentacles
Filter feeders with radioles
describe their digestive system
Foregut: buccal cavity, pharynx
(often eversible) with jaws
and teeth, and glands
Midgut: End of esophagus,
intestine with modified
stomach. Enzyme
production.
Hindgut: Mucus added to fecal
pellets, rectum, anus
Do they have a heart?
No real heart
Are respiratory organs present?
Yes, parapodia, branchiae in
tentacle crown
how to they maintain homeostasis?
Metanephridia
Explain their reproduction
No distinct gonads. Gametes formed from peritoneum and cells stored in coelom.
Fertilization external.
Many free-swimming benthic annelids produce epitokes
what type of cleavage?
Holoblastic, spiral cleavage
leading to a coeloblastula
what type of gastrulation?
Gastrulation by invagination or
epiboly
Special characteristics of earthworms?
No parapodia and reduced number of setae.
Reduced prostomium and peristomium.
Clitellum functions in reproduction
How do earthworms move?
Peristaltic contractions.
Setae used to anchor. Setae
can be retracted
explain NS and sense receptors of earthworms
Complex nervous system.
Tactile and chemoreceptors across body.
Specialized areas in an earthworm’s foregut?
Crop
Gizzard
Calciferous glands
Specialized areas in an earthworm’s midgut?
Typhlosole
Chloragogen cells
do earthworms have a heart?
2-5 pairs of hearts with valves
How do earthworms perform gas exchange?
across skin
what types of asexual reproduction in earthworms?
Transverse fission and fragmentation
Explain earthworm sexual reproduction
Simultaneous hermaphrodites.
Males: testes make sperm which are stored in seminal vesicles. Released into sperm ducts and out male gonopore during copulation.
Females: ovaries produce eggs. Released into coelomic space. Spermatheca store mate’s sperm
Special characteristics of leeches?
No parapodia and no setae.
Even more reduced prostomium and peristomium
Anterior and posterior suckers.
Dorsoventrally flattened.
Ectoparasites.
How do leeches move?
Inchworm-like crawling
What type of worm?
Leech
What type of worm?
Earthworm
What type of worm?
Annelid
What structure functions in leech reproduction?
Clitellum
