Review Questions
Which of the following periods is the earliest during which animals may have appeared?
- Ordovician period
- Cambrian period
- Ediacaran period
- Cryogenian period
Hint:
D
What type of data is primarily used to determine the existence and appearance of early animal species?
- molecular data
- fossil data
- morphological data
- embryological development data
Hint:
B
The time between 542–488 million years ago marks which period?
- Cambrian period
- Silurian period
- Ediacaran period
- Devonian period
Hint:
A
Until recent discoveries suggested otherwise, animals existing before the Cambrian period were believed to be:
- small and ocean-dwelling
- small and nonmotile
- small and soft-bodied
- small and radially symmetrical or asymmetrical
Hint:
C
Plant life first appeared on land during which of the following periods?
- Cambrian period
- Ordovician period
- Silurian period
- Devonian period
Hint:
B
Approximately how many mass extinction events occurred throughout the evolutionary history of animals?
- 3
- 4
- 5
- more than 5
Hint:
D