Flatworms & Roundworms Flashcards
Invertebrates 1 (36 cards)
What are the 3 groups of worms?
Platyhelminthes
Annelida
Nematoda
Which 2 groups are protostomes split into?
Lophotrochozoa
Ecdysozoa
What is helminthology?
Study of flukes, tapeworms & roundworms
What is the difference between parasites & parasitoids?
Parasite = not fatal to host
Parasitoid = fatal
What are the 2 types of parasite depending on where they live?
Endoparasite = inside host
Exoparasite = on host
In terms of reproduction, what must parasites do?
Reproduce within host
Get fertilised eggs/embryos out of host
In terms of their habitat, what must parasites do?
Recognise & contact new host
Get into new host
Find right location in host & stay there
In terms of survival, what must parasites do?
Withstand anaerobic conditions
Avoid host digestive & immune systems
Avoid killing host
How can some flukes alter snail behaviour?
How can they alter the snails’ appearance?
Cause them to seek light in the open so more likely to be eaten by bird
Cause eyestalks to resemble caterpillars
How can flukes alter the physiology of Potamopyrgus antipodarum?
Which hypothesis is this an example of?
Strong correlation between sexual reproduction & extent of nematode infection
Heavy load = sexual
Light load = asexual
Red Queen hypothesis
What is the common name fro Platyhelminthes?
Flatworms
Describe the features of Platyhelminthes.
> Simplest of the lophotrochozoans
Triploblastic
Aceolomates
25,000 species
Why are Platyhelminthes flat?
= cells near surface
No organs for transporting O2
–> Only simple organs for excreting waste
Which flatworm class is probably most similar to ancestral flatworm forms?
Turbellaria
= free living flatworms
How do motile flatworms move?
Beating broad bands of cilia
Describe the flatworm digestive system.
What do they feed on?
= mouth opening into blind sac
- highly branched sac increases SA
(no anus)
Living or dead animal tissue
- release digestive juices then suck digested food through pharynx
What is special about Schmidtea?
They’re regenerative
What is special about the Digenean life cycle?
5 stages:
miracidium, sporocyst, redia, cercaria, metacercaria
2+ intermediary hosts - 1st = mollusc Specificity towards molluscan host Asexual reproduction in intermediary hosts Sexual in vertebrate definitive host
What is the main characteristic of:
>Turbellaria (class)?
All non-parasitic forms
What is the main characteristic of:
>Trematoda (class)?
> Digenea (subclass)?
> Aspidogastrea (subclass)?
> Parasitic flukes
> Adults often in digestive tract of vertebrates
> Marine & freshwater fishes & turtles
What is the main characteristic of:
> Cercomeromorpha (class)?
> Monogenea (class)?
> Cestoda (class)?
> Typically attach w/ discs of hooks
> 1 host e.g. fish scales or frog bladder
> Tapeworms in organs of vertebrates
Which class are Monogenea in?
Cercomeromorpha
Describe what the Frog bladder fluke (Gorgoderina attenuate) does.
This is an example of which subclass?
Larva attach to tadpoles that hatch from eggs
- -> as tadpole metamorphoses into a frog, parasite migrates to host’s bladder
- -> parasite takes 3yrs to become adult
Monogenea
Which class are Cestoda in?
Cercomeromorpha
