Example test questions: Evolution
- The transition from reptilian jaw structure to mammalian jaw structure is characterized by what kinds of changes?
- Which of the following are found ONLY in present-day mammals and in ALL species of present-day mammals?
- 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)
- 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)
- 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)
- Describe the changes in jaw structure and hearing apparatus that accompanied the evolutionary transition from reptiles to mammals.
- Describe five characteristics of early mammals and indicate how each of these contributed to the success of mammals relative to their therapsid ancestors.
- (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?
- What were the earliest mammals like (in terms of size, diet and activity patterns)? How do we know?
- 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?