Platyhelminthes Flashcards
While most of the platyhelminthes are free living or endoparasites, Give an example of a taxa that has an ectoparasitic life cycle
Monogenea
Cells that secrete mucus in the epidermis of the Turbellaria are called
Rhabdites
Protonephridia function in A) waste disposal. B) respiration. C) osmoregulation. D) digestion.
A) Waste disposal
Which of the following groups includes ectoparasites of fish and amphibians? A) Monogenea B) Turbellaria C) Trematoda D) Cestoda
A) Monogenea
Cestodes are monoecious and lack a digestive tract. The reproductive units of the cestodes are called
Proglottids
In the digenetic trematodes, the first or invertebrate host is called the _________ and the second or final host, which is usually a vertebrate, is called the _________ host.
Intermediate, definitive
What is the phylogentic tree of platyhelminths?
True tissue -> Bilaterally symmetrical -> Protostome -> Lophotrochozoa (Or trochopore larvae) -> absent unsegmented coelom
What are the general Environment characteristics
Marine, Freshwater, Moist terrestrial, some times parasitic
What are the general Development characteristics
Acoelomate, Triploblastic, Bilaterally symmetrical, Dorsoventrally flattened.
What are the general Reproduction characteristics
Hermaphroditic, internal/cross fertilisation
What are the general Digestion characteristics
Single opening to the gut, or no gut.
Lateral canals with flame cells - Excretory system.
Diffusion across the body surface
What are the general Sensory characteristics
Paired anterior ganglia. Longitudinal nerve cord
What are the general Respiratory characteristics
No specialised respiratory circulatory systems.
What are the 4 major classes?
Turellaria (Free-living flatworms)
Cestoda (Tapeworms)
Monogenea (Ectoparasite)
Trematoda (Flukes)
What are the general characteristics of the class Turbellaria
Aquatic (Some terrestrial)
Free-living (Some parasitic)
Moves via a mucous layer (Adhesive/releaser glands) also with a ventral cilia
Acoels(Poorly formed gut/Elaborately branched)
Sexual/asexual
What are the general characteristics of the class Cestoda
Endoparasitic,
Has Scolex (Hooks/suckers for attachment)
Diffusion for nutrients.
No mouth or gut
Reproduction via Prolottid (Segment containing reproductive organs/fertilised eggs)
What is the reproduction cycle of a Cestoda
Prolottid breaks of adult form -> Leaves host via fecal matter -> eggs consumed via intermediate host (May enter more than one intermediate host) -> Enters definitive host -> Sexually matures -> Repeat cycle.
What is the Oncosphere stage of a Cestoda
A 3 paired hooked larvae stage
What are the general characteristics of the class Monogenea
Ectoparasite on fish
Life-cycle Adult produces eggs -> eggs hatch into Oncomiracidium (Larvae stage) -> Attach to new host -> Sexually mature -> Repeat
What are the main requirements of the parasitic life styles of this phyla
Reproduction (Getting the eggs out of host)
Locate (Detection of a host/entering the host)
Maintain position (Remaining in the ideal spot within a host)
Lack of O2 (The use of diffusion)
Defending from the host (Hiding in cells/Changing chemicals, ect)
Briefly describe the life cycle of a Opisthorcis sinensis (Human liver fluke)
Infected raw fish eaten by human -> Sinensis enters, develops to sexually maturity -> Miracidium released via faeces -> snail intermediate host -> develop into rediae -> Multiple cercariae leave snail -> Free-swimming, find host fish gills -> fish muscles then metacercarial cysts -> Repeat
