hard :(

• Phylum Ctenophora


  • Venus's girdle, Beroe cucumis
• Phylum Platyhelminthes


  • Freshwater and marine, also in soil
  • Endoparasites, as well as free-living form (Planarians)
  • Acoelomates, 3 germ layers
  • Bilateral, unsegmented, soft-bodied and dorsi-ventrally flattened
  • Include classes - Planarians, Flukes, Tapeworms
  • Mesenchyme between skin and gut
  • Body cover: epidermis. Syncytium + cuticle in endoparasites
  • Body support: hydrostatic skeleton
  • Muscular system: muscles in gastrovascular cavity (+) cilia
  • Digestive system: incomplete, one opening, diffusion
  • Respiratory system: diffusion
  • Circulatory system: none
  • Excretory system: flame cells (all over the body) that control the concentration of fluids, osmosis
  • Nervous system: simple, with two nerve cords running through the body and two simple "brains" ganglia (cluster)
  • Sensory system: simple eyes, statocysts
  • Reproduction: mostly hermafrodites with an indirect development, parasites - complicated cycles
• Class Turbellaria (Planarians)


  • Mostly free-living predators or scavengers, some parasites
  • Pigment cells (rarely colourless) in the epidermis
  • Most - one pair of ocelli - simple eyes (or more) may have statocysts (balance sensory receptor)
  • Sexual reproduction – hermaphrodites NO gonads
  • Asexual reproduction - many can clone themselves (high regeneration ability) or budding
• Class Turbellaria


  • Flatworm, Dugesia dorotocephala
• Class Trematoda (Flukes)


  • Cca 1-30mm, no celia, flat, rhomboid shape, blind
  • Parasites with usually 2 holdfasts (prísavky) which look like suckers
  • Complicated life cycle. Earliest hosts are usually snails in land or water, second are fish or arthropods and the definite host in which adults develop is a land vertebrate
  • Adults infest different parts of the definite host - intestine, lungs, liver...
• Class Trematoda


  • Common liver fluke (Fasciola hepatica)
• Class Cestoda (Tapeworms)


  • Endoparasites
  • Slender, very long bodies 20 m (the whale tapeworm is 30m long)
  • As adults found in the digestive tracts of vertebrates
  • Internal parasites without a mouth or gut
  • Skin absorbs nutrients (osmotrophy). Anaerobic metabolism.
  • Body structure: The head (scolex) attaches to the intestine of the definite host by hooks and suckers. The neck produces chain segments (proglottids) (up to 1500) by strobilation (asex. Rep.) they may overlap the previous one or not
  • Older segments are pushed to the tail tip and separate from the tapeworm. After detaching it carries eggs and leaves the host only as a sack of eggs (up to 100 000 eggs per worm)
  • As larvae they live in blood or tissues of an intermediate host, the create cysts with heads
  • Humans may be infected by consuming undercooked meat (pork, beef, fish)
  • Hermaphrodites (each segment contains female and male organs)
• Class Cestoda


  • Beef tapeworm (pásomnica dlhá), Pork tapeworm (– in humans)
• Phylum Nemathelminthes (Nematoda)


  • A very varied group of roundworms
  • Most are parasites, some free-living, adapted to almost all ecosystems
  • Body structure: slender body, tapered towards both ends. No segments. Pseudocoelomates. From less than a mm up to 1m
  • Body covering: epidemis. In parasites syncytium + cuticle
  • Body support: hydrostatic
  • Muscular system: a layer of muscle cells under the epidermis
  • Digestive system: tubular
  • Respiratory system: diffusion. Endoparasites - anaerobic.
  • Excretory system: flame cells (protonefrídie)
  • Nervous system: projections run from the inside of muscle cells to nerve cords (vice versa). 4 peripheral nerves run through the body. The nerves branch from a circular nerve ring
  • Sensory system: simple
  • Reproduction: mostly gonochoristic with visual sex. Dimorphism. Direct and indirect development - with or without an intermediate host
• Phylum Nemathelminthes


  • Giant roundworm, Human pinworm, Trichina worm, Plant pathogenic nematodes