Sponges, Rotifers, and Cnidarians Study Guide

  • Which kingdom do sponges belong to? - Animal

  • What phylum do sponges belong to? - Porifera

  • What phylum do rotifers belong to? - Rotifera

  • What phylum do jellyfish, hydras, corals, and anemones belong to? - Cnidaria

  • What class do “true” jellyfish belong to? - Scyphozoa

  • What class do hydras belong to? - Hydrozoa

  • What class do corals and anemones belong to? - Anthozoa

  • Parthenogenesis - a type of reproduction where an egg develops into a new organism without being fertilized by a male

  • Which group of organisms can reproduce by parthenogenesis - rotifers

  • What type of symmetry do cnidarians have? - radial symmetry

  • Are sponges multicellular or uni-cellular - multicellular

  • What does the phylum name “Porifera” mean? - “pore-bearing”

  • Which group of organisms are hermaphroditic - sponges

  • Hermaphroditic (being a hermaphrodite) - an organism has both male and female reproductive organs

  • Which phylum has members that have stinging tentacles - Cnidaria

  • Why are sponges considered Benthic organisms - because they live at the bottom of the ocean

  • What is the job of a choanocyte? And in what organism would you find a choanocytes? - create water flow, capture food particles, and get rid of waste

  • How do sponges eat? - filter-feeding

  • Are rotifers motile, sessile, or both? - BOTH

  • How do rotifers eat? - they create a current

  • What type of digestive tract is found in the rotifers? - one way

  • What are nematocysts and within what group would you find them? - stinging structure; found in jellyfish, corals, and anemones

  • What type of habitat would you find cnidarians living in? (Marine, freshwater, or both) - BOTH

  • What are statocysts - balance organs that help organisms sense gravity

  • What are ocelli? - simple eyes that detect light

  • How long have cnidarians been around? - over 500 million years

  • What are cnidarians named after? - cnidocytes

  • How do cnidarians reproduce ? - sexually (spanning) and asexually (budding)

  • What is polymorphism? - the occurrence of two or more clearly different morphs or forms

  • What is the mortality rate of a box jellyfish species? - 20%

  • How many people has the Portuguese man-of-war killed? - 3

  • What is the largest jellyfish species - arctic jellyfish species

  • How do sea anemones and corals differ? - sea anemones have a soft structure, while corals have a stiff and stronger structure

  • What are coral exoskeletons made of? - calcium carbonate