12 Flashcards
Aschelminthes
Chaetognatha
Nematode
Nematopmorpha
Priap7lida
Rotifera
phylum in aschelminthes
Chaetognatha
Nematoda
Nematomorpha
\Priapulida
Rotifera
Chaetognatha spp
150
Nematoda spp
27,000
Nematomorpha spp
365
Priapulida spp
22
Rotifera includes
Acanthocephala
Acanthocephala spp
3300
Chaetognatha habitat
marine
Chaetognatha diet
predatory
what describes where chaetognatha swim
nektonic
nektonic
swims in the open water
column
Chaetognatha
arrow worm
Chaetognatha molecular phylogenetic analyses
place them with
Protostomia
however has deuterostome-like characrteristics
Chaetognatha nervous syste,m
ventral nerve cord
circumoesophageal connectives
what deuterostome-like characteristics does Chaetognatha have?
-multiple eucoelomic cavities arising from process similar to enterocoely
-the mouth does not develop from the blastopore
what is phylum chaetognaths suggested to be?
transitional phylum b/w proto- and deuterostomes
however, molecular studies say protostome spiralian clade Gnathifera
what supports chaetognaths as transitional phylum
fossils from Burgess Shale
morphological features of chaetognaths
three sets of eucoeloms
post-anal tail
-fins
-eyes
-grasping spines
chaetognaths sexes
hermaphrodites
sperm transfer methods chaetognaths
sperm placed right at
the entrance to one of the two female genital
openings
or
jizz placed on body and streams over the epidermis and enters female shi
fertilization chaetognaths
internal
development Chaetognatha
direct
neither mouth nor anus come from the blastopore
how do Chaetognatha subdue prey
neurotoxin: tetrodotoxin
how do Chaetognatha avoid preation
transparent
Phylum Rotifera habitat
freshwater,
marine and terrestrial
Acanthocephala
all endoparasites
included in rotifera
why were rotifers and acanthocephalans considered closely related
unusual syncytial epidermis with a dense intracellular protein layer
Non-acanthocephalan Rotifera
among the
smallest of all bilaterians
Non-acanthocephalan Rotifera movement
cilia via the corona
rotifers body cavity
pseudocoelomate
Non-acanthocephalan Rotifera solitary or
colonial
solitary few are
colonial
are Non-acanthocephalan Rotifera free-swimming or sedentary
most are free-swimming
some are sedentary
what do sedentary Rotifera do
build cases out of sand
or their own fecal pellets
what do some rotiferas protect themselves with
armor called a
lorica
eutely
no longer grow by adding
cells but though each cell getting
larger
rotifers pharynx has
mastax
mastax
internal mouthparts inside
the pharynx
made of smaller parts called trophi
Gnathifera what do they share in common
complex mouthparts of Rotifera
Non-acanthocephalan Rotifera what do they yse for water balce
protonephridia
do Rotifera have nervous system
simple nervous system
Rotifera eyes
eyespots
detect light but
don’t form images
development Rotifera
direct development
sexes Rotifera
several hundred species are completely parthenogenetic- never have males
in species w males and females what do they engage in
cyclic
parthenogenesis
cyclic parthenogenesis of rotifers
-diploid daughters by amictic females when environment good
-haploid sons by mictic females when
environment deteriorates
-males copulate w females
rotifers that never have males
anhydrobiosis- dont die when dried out
cilia in rotifers functions
both locomotion and feeding
rotifers diet
small particles or
active hunters
Seisonidea
group of ectoparasitic rotifers live on the
bodies of crustaceans
Seisonidea coronas
very reduced
Seisonidea reproduction
sexually
clade thought to be sister to the parasitic Acanthocephala
Seisonidea
Acanthocephala
group of Rotifera that is exclusively endoparasitic
what are the hosts of Acanthocephala
vertebrates (final hosts) and insects and crustaceans (intermediate hosts)
Acanthocephala characteristics
large pseudocoelom
have no mouth or gut
spiny anterior end
sperm transfer Acanthocephala
copulation
difference b/w acanthocephalans and free living rotifers lifecycle
clear larval stages in acanthocephalans
whart are acanthocephalans famous for
manipulation of intermediate hosts
