platyhelminthes, annelida and nematodes Flashcards
what are the key characteristics of worms
bilaterally symmetrical
triploblasts
What kind of worms are platyhelminthes?
Flatworms
how do platyhelminthes excrete?
via flame cells
how do platyhelminthes respire?
just through diffusion
What are the classes of platyhelminthes?
turbellaria, monogenea, trematodes and cestoda
is the class tubellaria parasitic or free living?
mostly free living
are tubellaria aquatic or terrestrial?
both
is tubellaria predators or scavengers?
can be either
what kind of eyes and mouth do tubellaria have?
they have ocelli and a pharynx (eating tube) often in the middle of the worm
how big are tubellaria?
1mm to 50mm in size
what are the main characteristics of the class monogenea?
they are ectoparasites of fish
small
hook attachment organ on rear
simple life cycle with only one host
what are the main features of the class trematodes?
parasitic flukes
endoparasites
liver, lung, intestines, blood
complex lifestyles with 2 or more hosts
hooks at mouth and underside of worm
how do they make their lifecycle continue?
they manipulate host behaviour
what is the class cestoda?
tapeworms
what are the features of the class cestoda?
can be found in beef, pork and fish
no digestive system
attach via scolex
medium complexity in lifecycle
what are proglottids and which class can you find them in?
they are segments of cestoda that are like packages of reproductive organs that are excreted in feces so the lifecycle restarts
what phylum are segmented worms, bristle worms and leeches?
annelida
Of the annelida phylum, what does it mean to have a metameric body?
a serial repition of functional units that make up the body that are all very similar
do annelids have circulatory, respiratory, nervous and excretory systems?
yes all of them
What is a hydrostatic skeleton and which phylum does it belong to?
annelida
a hydrostatic skeleton is a fluid filled coelum, and with the combination of longitudinal and circular muscles contracting against the fluid in the coelum assists these animals in movement
What are setae in annelida?
little hairs on the outside of the body made of chitin that assist in movement by gaining traction on surfaces
what phylum are the classes polychaeta and clitellata?
annelida
what are polchaeta and what do they do?
they are bristle worms
mostly marine
they are mobile predators or filter feeders
well-defined heads
parapodia
what worms are included in the clitellia class?
earthworms and leeches
what is clitellum?
a thickening of the epidermis at female genital pores that secrete egg cocoons
do clitellia have setae?
yes, but reduced in comparison to polychaeta
how do clitellum reproduce?
they are hermaphrodites, so both worms give and receive sperm
what suckers do leeches have?
posterior and anterior
do leeches have coelomic compartments?
no they’d ont
what kind of feeding style do leeches have
carnivorous, detritivores or parasites
are nematodes ecdyzoans?
yes they have a cuticle that sheds when they grow
what kind of muscles do nematodes have?
only longitudinal
do nematodes have a ganglia and nerve cords
yes
what kind of digestive system do nematodes have?
a complete one
are nematodes parasitic?
yes
are nematodes dioecious?
yes, the males are smaller than females
Are platyhelminthes free-living or parasitic?
they are both
How do platyhelminthes respire and what repiratory organs do they have?
They have no respiratory organs oxygen diffuses in and out.
Recall cephalisation in platyhelminthes
They do have cephalisation. They have a ganglia and nerve cords.
describe the gut of platyhelminthes
incomplete
How do Platyhelminthes excrete?
Via flame cells
