This time period started with the explosion of

Match up the description with the appropiate geologic era/eon. Note: matches are randomized with each attempt.

Question options:
This time period started with the explosion of
visible life and the beginnings of hard parts such
as shells and teeth. Initially common fossils are of
marine organisms, but by the end of ther era there
was the rise of land plants and vertebrates (both
marine and land). Ended with the largest known
extinction event in Earth’s history. Between 542251 million years ago.

Known as the age of the dinosaurs, but also saw
rise in the diversity of true mammals and the first
flowering plants. The marine realm had large
marine reptiles and amminoids (relatives of the
squid). Between 251-65 million years ago.

Referred to as the age of mammals, due to the
increase in size and diversity of mammals, but
could also be known as the age of frogs, or age of
insects, or the age of grasses as these groups
also diversified. Between 65 million years ago to
the present.

1
Proterozoic Eon
.
2
Paleozoic Era
.
3
Mesozoic Era
.
4
Cenozoic Era
.

Time between 2.5 billion to about 542 545 million
years ago , when single celled life dominated and
saw the rise of atmospheric oxygen

2. What is the order of geologic periods (smaller slices of time) within the Mesozoic and Cenozoic Eras? Oldest is
1.

Question options:
Quaternary

Cretaceous

Jurassic

Paleogene

Neogene

Triassic

3. This slice of geologic time is very young (less then 5 million years) and it characterized by large mammals in N.
America such as the Wooly Mammoth and mulitple glaciation events. Glacial deposits of this age cover part of
Table Mesa here in Boulder.

Question options:
Pleistocene Epoch (2.6 million years ago (mya) – 11,700 years ago)

Cretaceous Period (145 – 65 mya)

Permian Period (299-251 mya)

Cambrian (542-488 mya)

4. This slice of geologic time saw a rise in the diversification of dinosaurs along the edge of a Western Interior
Seaway that divided east and west N. America. Also saw the rise of flowering plants.

Question options:

Permian Period (299-251 mya)

Cambrian (542-488 mya)

Pleistocene Epoch (2.6 million years ago – 11,700 years ago)

Cretaceous Period ( 145- 65 mya)

5. his slice of geologic time ended with the formation of the last supercontinent Pangea at 251 million years ago. It also coincided with the
largest known mass extinction in Earth’s history, where over 90% of life died out.

Question options:
Pleistocene Epoch (2.6 million years ago to 11,700 years ago)

Permian Period (299-251 mya)

Cretaceous Period (145-65 mya)

Cambrian (542-488 mya)

6. This slice of geologic time is identified with the first hard parts in the rock record. What drove this "explosion" of life is still being deba

some hypotheses sugegst the abundance of shallow seas around the equatorial region after the rifting of Rodinia may have something t
with it.

Question options:
Cambrian (542-488 mya)

Permian Period (299-251 mya)

Cretaceous Period (145-65 mya)

Pleistocene Epoch (2.6 mya – 11,700 years ago)

7. What is the order of geologic periods (smaller slices of time) within the Paleozoic Era? Oldest in 1.

Devonian

Permian
Ordovician

Carboniferous (Mississipian & Pennsylvanian)

Cambrian

Silurian