Example test questions: Evolution

Multiple choice

  1. The transition from reptilian jaw structure to mammalian jaw structure is characterized by what kinds of changes?
  2. Which of the following are found ONLY in present-day mammals and in ALL species of present-day mammals?
  3. Therapsid reptiles (a. had no specializations for more efficient eating, b. showed attachment of jaw muscles to the zygomatic arch, c. had a temporal shield, d. gave birth to live young)
  4. What characteristic is used to distinguish the earliest mammals from mammal-like reptiles? (a. dentary/squamosal jaw articulation, b. enucleate erythrocytes, c. presence of hair, d. heterodont dentition)
  5. Synapsids are extinct mammal-like reptiles that had (a. a temporal shield, b. a single opening in the cranium behind the orbit, c. the mandible being made up of a single bone, d. a dentary-squamosal jaw articulation)

Short answer

  1. Describe the changes in jaw structure and hearing apparatus that accompanied the evolutionary transition from reptiles to mammals.
  2. Describe five characteristics of early mammals and indicate how each of these contributed to the success of mammals relative to their therapsid ancestors.
  3. (a) Describe 3 "mammalian" characteristics that were also present in therapsid reptiles. (b) Describe 3 ways in which the first mammals were distinct from therapsids. (c) Why might these early mammals have persisted, while the therapsids went extinct?
  4. What were the earliest mammals like (in terms of size, diet and activity patterns)? How do we know?
  5. Contrast the skeletal structure of reptiles with that of mammals. Your answer should include at least 5 skeletal features. What is the significance of each difference you have described?