Phylum Cnidaria

Nota:

• of or produce by the sea

1. senssile

   Nota:

   • more or less permanently attached to a suband do not move
2. benthic

   Nota:

   • live in the bottom in aquatic habitats may be attached to or resting on the bottom or live in bottom sediments  very little light exposure

Nota:

• spend their lives in the upper waters of oceans

1. float or swim weakly
   1. can't swim against current
   2. cant chase potential food
2. challenges

1. hydra
   1. exist in fresh water
      1. located attached to
         1. bottom
         2. to plants
         3. hanging from the surface
   2. only has simple polyp stage
   3. cnidocytes

      Nota:

      • cells that have a nematocyst which releases a tube that stings then releases a toxin into prey r wraps around a prey
2. sea anemones
   1. marine
   2. have polyp stage during life history
   3. can grow large
   4. cnidocytes

      Nota:

      • cells that have a nematocyst which releases a tube that stings then releases a toxin into prey r wraps around a prey
3. feeding behavior

Nota:

• no anterior or posterior ends. and a single plane going through a central axis would result in dorsal and ventral ends that are not differentiated

1. outer epidermis

   Nota:

   • out epithelial tissue that separate the outside from the inside
2. gastrodermis

   Nota:

   • inner epithelial tissue
3. gastular cavity

   Nota:

   • where food goes to be exposed to lubricating mucus and digestive enzymes. then is phagocytosis occurs by special cells, and enter a food vacuole to complete digestion