Chapter 15: Diversity of Animals

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Introduction to Animals

  1. How are animals different from fungi?
  2. What are the characteristics of all animals?
  3. What animals don’t have nerve or muscle cells?
  4. What are the closest living relatives (protists) to animals?
  5. What are the characteristics that the Cnidaria and Ctenophora share?
  6. Describe two ways that choanoflagellates are similar to sponges.
  7. What is the difference between diploblasts and triploblasts?
  8. What organisms are diplobastic?
  9. Be able to identify the endoderm, mesoderm, and ectoderm.
  10. What doe the ectoderm develop into?
  11. What does the endoderm develop into?
  12. What does the mesoderm develop into?
  13. What germ layer does your stomach come from? Your liver? Your muscle? Your skin? Your brain?
  14. Cnidarians include three groups of organisms known by their common names. What are they?
  15. What group of organisms lack nerves?
  16. What groups of organisms have a nerve net?
  17. What is a nerve net?
  18. What is a centralized nervous system?
  19. What is a ganglia? What is a cord?
  20. What group of animals are asymmetrical?
  21. What groups of animals are radially symmetrical for their whole lives?
  22. What is an advantage of being radially symmetrical vs. asymmetrical?
  23. What is are two advantages of being bilaterally symmetrical.
  24. What is cephalization?
  25. What concentrates in the cephalized regions?


  1. What is a coelom? What are two functions of a coelom?
  2. Coelomates are broken into two big groups. What are those groups called?
  3. Coleomates all share three characteristics in common. What are they?
  4. What are two differences between protostomes and deuterostomes?
  5. What group of animals are transparent, gelatinous diploblasts that prey on plankton and move by cilia?
  6. What group of animals are suspension feeders that are sessile as adults, but mobile as larvae, and are asymmetrically arranged?
  7. What group of animals are bilaterally symmetrical worms that are triploblastic but lack a coelom. They live in mud and move via cilia.
  8. What two groups are protostomes split into?
  9. What is the morphological difference between the lophotrochozoa and the ecdysozoa?
  10. What is molting? Cuticle? Exoskeleton?
  11. What two things do all flatworms have in common?
  12. What are the three groups of flatworms?
  13. What group of flatworms are free living flatworms that are hunters and scavenger in the oceans?
  14. Which group of flatworms are the “moochers of the animals kingdom”? They are endoparasitic tapeworms that lack a mouth and a digestive system.
  15. Which group of flatworms are endoparasites that gulp host tissues, but do have a digestive tract?
  16. What do segmented worms all share in common?
  17. What are the four groups of mollusks? What do they all have in common?
  18. What group of organisms are suspension feeders with 2 shells on a hinge?
  19. What group of organisms have a large muscular foot and radula but lack a shell?
  20. What group of organisms have a large muscular foot and radula with a shell of 8 plates?
  21. What four groups of organisms do the cephalopoda include?
  22. What characteristics to all cephalopods have in common?
  23. What are the physicals characteristics of roundworms?
  24. What are the most abundant animals on earth (in terms of numbers of organisms)?
  25. What are the most species diverse animals on earth?
  26. What group of organisms have segmented bodies and limbs, but lack jointed limbs and an exoskeleton, are microscopic and feed by sucking fluids living on the floor of aquatic environments?
  27. Why are members of the Tardigrada so amazing?
  28. List 6 characteristics that members of the Arthropoda share?
  29. What are the four groups of Arthropoda?
  30. How can you differentiate between a millipede and a centipede? List two ways.
  31. Insects have 3 tagmata. What are they?
  32. What structures are on the head of insects?
  33. What are the common names of members of Crustacea?
  34. What characteristics to members of the Crustacea all share in common?
  35. What do all Deuterostomes share in common?
  36. What are the three phyla of the Deuterostomes?
  37. Why are Asteroidea (i.e. starfish) considered part of the group Bilateria?
  38. What is the body plan of members of the Echinodermata?
  39. What characteristics do sea stars (star fish) have in common?
  40. Starfish have sex with their arms….weird!!!
  41. What do sea urchins eat?


  1. Members of the cepholochordata are known as lancets. From an evolutionary perspective, why are these organisms so important?
  2. What physical characteristics do members of the cephalochordate share? How do they feed?
  3. What is a notochord?
  4. Do all chordates have a vertebral column?
  5. What member of the Chordata has an exoskeleton? What is the exoskeleton called?
  6. List two characteristics that all vertebrates have in common.
  7. What are five of the major innovations in vertebrates in the order that they appear in the fossil record?
  8. What were the first four-legged land creatures known as?
  9. Why was the amniotic egg so important for the success of animals on land?
  10. What is a placenta; and how is it related to the amniotic egg?
  11. Two of the most primitive vertebrate groups lack jaws. What are they called?
  12. What group of organisms are the link between fish and tetrapods?
  13. What is the difference between a lobe-shaped fin and a ray-shape fin?
  14. Why are caeclians so strange?
  15. What are the characteristics of the members of Amphibia?
  16. What do mammals, lizards, turtles, and birds have in common that fish, frogs and lampreys don’t share?
  17. What are the three characteristics of mammals?
  18. Be able to differentiate among the mammalian groups: monotremes, marsupials, and eutherians? Which group do humans belong?