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Sponges, Cnidarians, and Worms
animal that has no backbone
Cnidarian or Colenterate
invertebrates that have stinging cells to capture food and defend themselves; stinging cells are called nematocysts; sea anemone, jellyfish, hydra, and coral
Roundworm or Nematoda
has a digestive system that is like a tube, open at both ends; round worms, hookworms
Flatworm or Platyhelminthes
flat,wide and as soft as jelly; planarian, tapeworm, fluke
What planarians use to detect light
The reason sponges are first and Echinoderms are last in the invertebrate groups
Sponges are the simplest; and echinoderms are the most complex
Simplest organism with a brain?
sense organs are in the front, distinct front and back, have more organs, more efficient
Live in water, no specific head or tail, moves slowly
Segmented Worms or Annelida
body is made up of many linked sections called segments; earthworms, leeches, bristleworms
Sponge or Porifera
Invertebrates animals that have no body symmetry, never have tissue or organs, one opening; barrel sponge, elephant sponge