REN R205 Lecture Notes - Lecture 6: Jellyfish, Flatworm, Cestoda
21 Sep 2016
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Document Summary
Cells can change from one type to another. Spicules are actually mineral angular things, hold living cells together. Pump water through pores, ltering food from the water. Freshwater sponges are small and greenish, since algae live symbiotically in them. Two body types in life cycle: one that is jelly- sh like (the medusa-looks like a jelly sh), and one that is more like an anemone (the polyp-looks like an anemone) In eastern canada and usa there is a freshwater medusa. Kill their prey using stinging cells, called nematocysts. Hydras are simple in construction, without internal organs. Non-segmented (body not divided into segments) worms that are more or less round in cross section. Important in the soil fauna, in fresh water ecosystems, as parasites, and as economic pests. Livestock parasites, e ect plants, e ect birds, etc. Free-living or parasitic, and many are important internal parasites of vertebrates. Vary from dorsoventrally attened atworms and ukes, to the quasi-segmented tapeworms.
