7 Lifeforms have changed throughout Earth's geologic history. Scientists learn about these changes by studying the fossil record.
For example, scientists have learned when different groups of organisms first appeared. These events can be placed within
specific periods on the geologic time scale, which is shown below.
Geologic Time Scale
Precambrian
Phanerozoic
EON
Archean Proterozoic
Paleozoic
Mesozoic
Cenozoic
ERA
Tertiary
Quaternary
PERIOD
Neogene
Paleogene
Ordovician
Silurian
+
Devonian
Triassic
Carboniferous
Permian
Jurassic
Cretaceous
Paleocene
Eocene
EPOCH
Miocene
Pliocene
Pleistocene
Holocene
ABCD
time
Today
Formation of
the Earth
Fishes with jaws first appeared during the Silurian period, and dinosaurs first appeared during the Triassic period. Large
mammals first appeared after both dinosaurs and fishes with jaws.
Using this information and the geologic time scale above, choose the period in which large mammals first appeared.
Session Score: 83% (5
OA
Cambrian
B
Tertiary
Session Timer: 17:32