Phylum Platyhelminthes Flashcards
Platyhelminthes embryonic tissue layers
Ectoderm
Mesoderm
Endoderm
3rd tissue layer between epidermis and digestive cavity
Mesoderm
Function of mesoderm
allows for development of muscle layers in body wall
allows for more elaborate organs, specialization, and greater division of labor than in cnidaria
The only internal space
digestive cavity
Advantages of flat body
allows them to rely on diffusion for exchange of gasses, nutrients, and wastes
Acoelomate
no body cavity
what does embryonic tissue ectoderm turn into
epidermis
what does embryonic tissue mesoderm turn into
Parenchyma
what does embryonic tissue endoderm turn into
Gastrodermis
The 2 layers surrounding body wall
Circular muscle
Longitudinal muscle
Feeding and Digestion
Carnivores
Endoparasites
Incomplete digestive tract
Respiration
No respiratory system
Gas exchange through flattened body wall
Excretion
Wastes like ammonia eliminated via diffusion through body wall
Other primitive systems include protonephridia
Asexual reproduction
Fission
Regeneration
Budding
Polyembryony
Sexual reproduction
Hemaphraditic
Platyhelminthes classification
Turbellaria
Monogenea
Trematoda
Cestoda
Turbellaria characteristics
Free living
Ventral mouth
Locomotion by creeping on cilia and mucous
Monogenea characteristics
Endoparasites on skin or gills of fish
Simple life cycle
No intermediate host
Trematoda characteristics
All parasitic
Endoparasitic flukes
Parasite in blood or digestive system
Up to 5 developmental stages in 2 or more hosts
Cestoda characteristics
All parasitic
Endoparasites in intestines
Bud long chains of proglottids
