Exam 1 - Cnidarians Flashcards
What does cnidaria mean in Greek?
nettle.
Where do you find cnidarians?
entirely aquatic, mostly marine, mostly shallow.
How are cnidarians organized?
tissue-level: diploblastic with an endoderm and exoderm.
What is mesoglea?
non-cellular, jelly-like protein.
What is a cnidarian body plan?
radial symmetry, single mouth, no head, no anus.
What is cnidarian diversity?
> 9000 species, fossils from >580 mya.
What is the cnidarian digestive system?
single digestive opening with cells that secrete digestive enzymes.
Do cnidarians have a nervous system?
no, but they have a nerve net that helps coordinate swimming.
True or false: cnidarians do not have a circulatory system.
True.
How do cnidarians exchange gases?
diffusion.
What is the only organ in cnidarians?
gonads.
What are cnidocytes?
cells that contain a stinging organelle called a nematocyst.
How do cnidarians eat?
prey on organisms using nematocysts, absorb organic chemicals, filter-feed, and symbiotic algae.
How do cnidarians reproduce?
medusa stage and polyp sage, both an asexual and sexual phase of life, hydrozoan cycle is from polyp to medusa.
Hydrozoa
water animal, polyp and medusa stage.
