Ch 13: Annelida Flashcards
6 annelid features
- most have a segmented body
- an obvious coelom
- protostome embryonic development
- chitinous chetae
- excretion via metanephridia
- marine spp have a trochophore larva
2 coelom advantages
- hydrostatic skeleton
- provides space for viscera
4 anatomical features of class Polychaeta
- head consists of prostomium and peristomium
- segments bear pairs of parapodia
- body wall has outer cuticle w/ protein fibers
- circular and longitudinal muscles
parapodia features (2)
- surface used for gas exchange
- carry cheatae for grip and protection
polychaete movement (2)
- burrowing spp pull themselves forwards w/ eversible proboscis
- some swim w/ undulating motion
muscular eversible pharynx may have
jaws
polychaetes circ system
closed
3 features of polychaetes circ system
- no heart; contractile vessels and valves ensure one way flow
- segmental vessels lead to capillary beds around gut, body wall, parapods, metanephridia
- hemoglobin and other pigments, but not in cells
2 funct of the 2 polychaete metanephridia
- collect coelomic fluid w/ cilia
- waste exits via nephridiopore
what do polychaetes secrete
NH3
what do polychaetes reabsorb (3)
water, salts, amino acids
4 sensory organs in polychaetes
- tactile
- chemoreceptors
- statocysts
- eyes
sexes in polychaetes
separate
fert in polychaetes
open
how are gametes of polychaetes prod?
by meiosis of cells lining coelom
3 ways polychaete gametes can exit coelom
- nephridiopores
- special ducts
- rupture of body wall
epitoke
nereids prod a special sexual stage - just for repro
how are epitokes created
strobilization
3 adaptations epitokes have for swimming
- bigger eyes
- enlarges muscles
- parapods
errant polychaetes either ? or ?
crawl along the bottom, swim
some errant polychaetes are in symbiotic relation to
a larger invert
diets in errant polychaetes (3)
predators, scavengers, herbivores
3 adaptations pelagic polychaetes have for swimming
- flattened bodies
- transparency
- big parapods
3 things tube dwelling polychaetes tubes may be made from
- CaCO3
- protein
- cemented sand
where are pogonophorans found? (3)
deep sea vents, methane seeps, whale falls
what is unique about where pogonophorans are found?
all temp habitats
what do pogonophoran tubes possess?
chitin
what do pogonophorans have a symbiotic relationship w/?
chemosynthetic bacteria
pogonophoran gut
none; simply collect gases for the bacteria
3 features of class clitella
- clitella - external, glandular ring
- hermaphrodites
- permanent gonads
clitellum
external glandular ring that secretes mucus which aids in sperm transfer, produces albumen, forms egg cocoon
2 adaptations Oliogochaeta/earthworms have for burrowing
- no parapods
- fewer chetae
2 things CaCO3 balls are for
- rid org of CO2
- useful for mechanical digestion
how many pairs of hearts do earthworms have
5
how many blood vessels do earthworms have
2 - dorsal and ventral
how are 1/5th of N-wastes expelled in earthworms
diffused across the cuticle
how does gas exchange in earthworms occur
diffusion across cuticle
3 ways an earthworm keeps its cuticle moist
- moist habitats
- coelomic fluid leaks from pores
- mucus keeps surface moist
do earthworms have statosysts?
no
3 repro ways in earthworms
- hermaphrodites (sexual)
- parthenogenesis in patchy habitats
some spp repro by fragmentation
parthenogenesis
prod diploid eggs that don’t need fert
4 repro steps earthworms
- sperm transferred w/in mucus ring formed by clitellum
- stored in spermathecae
- eggs placed in 2nd mucus ring later which closes to form a ‘cocoon’
- direct development
3 things earthworms do for soil
- mixing and aeration
- bring nutrients towards surface
- break down soil
why are all earthworms in Canada exotic?
glaciation destroyed all local spp
hirudinea
leeches
what do leeches not have
chetae
3 int features of leeches
- no internal septa
- body usually flattened
- coelom mostly filled w/ connective tissue and sinuses
do leeches have a clitellum
yes; not obv
leech locomotion (2)
- undulating swimmers
- inch along w/ suckers
which sucker do leeches attach w/
posterior
where are leeched mouths
in anterior sucker
how do leeches create a wound before sucking ur blood (2)
- enzymes
- saw-toothed jaws
pouches in digestive system hold blood up to ?x body weight
10
class echiura features (3)
- unsegmented
- ciliated proboscis for deposit feeding
- marine bottom dwellers in U shaped burrow
class sipuncula features (3)
- unsegmented burrowers
- anterior introverts
- deposit feeders who burrow in bottom or hide in crevices
what does it mean to be an anterior introvert?
can take anterior end of body and invert/hide it inside rest of body
