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protostomeschapter 33
poriferaeumetazoa
bilateria
cnidaria ctenophora
deuterostomiaprotostomia
lophotrochozoa
ecdysozoahemichordata echinodermata
chordata
gnathifera
gastrotricha
platyhelminthes nemerteagnathostomulida
rotifera acanthocephala
entoprocta
ectoprocta
mollusca
annelida
nematanematomorpha
tardigrada
arthropoda
onychophora
panarthropoda
acoela
root
rotifers• Phylum Rotifera—rotifers
• general characteristics• mastax• Marine or freshwater
filter-feeders• myxis
• Phylum Acanthocephala• proboscis with spiny hooks
• no digestive tract• protonephridia• dioecious• syncytial outer surface
• lacunar system distributes nutrients
flatworms• Phylum Platyhelminthes—
platy-flat, helmins-worm• Free-living or parasitic• Bilateral symmetry • Nervous system• Nutrition and Digestion
• Carnivorous or parasitic• Sac-like g-v cavity
Pharynx
Gastrovascularcavity
Mouth
Eyespots
Ganglia Ventral nerve cords
classification• Class Turbellaria
• Mostly free-living • Marine or freshwater• Predatory or detritivorous• Amazing regenerative powers
spine
distal cytoplasm
muscle
golgi
nucleus
tegument cell body
mitochondrion
parenchymal cell
flukes• Class Trematoda—flukes
• Vertebrate endoparasites• Adhesive sucker(s) or
hooks• Often with a multi-stage
life cycle
• Class Monogenea—• oncomiracidium (ciliated larva)• opisthaptor
prothaptor
mouth
sucker
opistaptoranchor
• Class Cestoda—tapeworms• scolex and proglottids • Monoecious• No gut
thus the area for absorption of nutriments. The bases ofspine-like and blade-like microtriches have an electron-dense ridge at their anterior edge. According toMacKinnon and Burt (1983) this ridge may function inpreventing the microtriches from bending forward andthus losing their grip against the mucosal epithelium ofthe host intestine.
The ultrastructure of microtriches can be used as ataxonomic character to be added to other characteristics(Richmond and Caira 1991; Hoberg et al. 1995; Cairaand Tracy 2002; Ivanov and Brooks 2002; Ivanov 2004;Gil de Pertierra 2004, 2005). In our opinion moreinformation of microtriches pattern could be useful forthe determination of species in proteocephalideans.
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cytoplasm of tegumentmicrotrich
circular musclelongitudinal muscle
mitochondria
molluscs• Phylum Mollusca—
molluscs, mollusk• Marine, freshwater,
terrestrial trochophore
veliger
• Class Gastropoda• Univalve or having a lost or reduced valve• Classification—subclasses
• Prosobranchia• Opisthobranchia• Pulmonata
• Class Bivalvia—• No head or radula• bivalve -
• adductor muscles
• Class Cephalopoda—• Reduced or lost shell in most