4: Annelida Flashcards
phylum:
- segmented worms
- lophotrochozoan
- found in marine, freshwater, moist terrestrial habitats
annelida
true segmentation; work together for the whole organism
metamerism
the segments; contain repeated external and internal morphological features
annuli
chitinous extensions in each segment of most species (except leeches) to aid in movement
chaetae/setae
partitions in annelids; prevent movement of fluids between segments
septa
annelid coelom is formed via _____
schizocoely
most annelids (except leeches) have a fluid filled coelom that serves as a _____
hydrostatic skeleton
a pair of ___ facilitate excretion
nephridia
annelids have a closed circulatory system with ____ (“hearts”) for pumping blood
aortic arches
asexual reproduction occurs via ____ and ___; capable of complete regeneration
fission; fragmentation
used as a descriptive term to refer to annelids with many setae
polychaete
3 historical classes of annelida:
polychaeta
oligochaeta
hirudinea
annelida class:
- mostly marine
- have multiple setae per segment
- usually predators or scavengers
- sensory organs highly developed
errant polychaetes
fleshy appendages of each segment in errantia; primary respiratory organs
parapodia
annelida class:
- contains sedentary polychaetes and oligochaetes that live in tubes or burrows
- parapodia small, used as anchor
- like errantia w tentacles around head for feeding
sedentaria
clade:
- earthworms and relatives and leeches
- have fewer cheatae
- contains clitellum
- all monoecious
clade clitellata
ring structure in the skin that secretes mucus for reproduction
clitellum
annelida class:
- paraphyletic
- setae less numerous than in polychaetes
oligochaetes
along the esophagus reduce the concentration of calcium ions in the blood and regulate acid-base balance
calciferous glands
dorsal infolding of intestine that increases SA
typhlosole
large axons that have increased rates of conduction
giant axons
order in annelida:
- true leeches
- completely lack setae
- have exactly 34 segments
- mostly freshwater
- many carnivores, some parasites
order hirudinea
coelom in leeches is filled w connective tissue and a system of spaces called ___
lacunae
- leeches are ___
- cross-fertilization occurs during mating
- sperm transferred by ____
monoecious; hypodermic impregnation
