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. Therapsids (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 stem amniotes and non-mammalian therapsids? (a. dentary/squamosal jaw articulation, b. enucleate erythrocytes, c. presence of hair, d. heterodont dentition)
5. Synapsids all shared this characteristics (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 stem amniotes to mammals.
2. Describe five characteristics of the earliest mammals and indicate how each of these contributed to the success of mammals relative to the proto-mammals that went extinct.
3. (a) Describe 3 characteristics that distinguish present-day mammals from other vertebrates but were shared with other therapsids. (b) Describe 3 ways in which the first mammals were distinct from other therapsids that went extinct. (c) Why might these early mammals have persisted, while the other therapsids went extinct?
4. What were the earliest mammals like (in terms of size, diet, and activity patterns)? How do we know this or why do we think this?
5. Contrast the skeletal structure of stem amniotes with that of mammals. Your answer should include at least 5 skeletal features. What is the significance of each difference you have described?