Geologic Time
The longest interval of time is called _________.
An eon
The atmosphere was filled with poisonous gas during the:
Archean Eon
Proterozoic Eon
Buildup of oxygen; first eukaryotes.
Phanerozoic Eon
Current eon
Longest interval of geologic time.
Eon
Major divisions of geologic time within each eon; identified by major changes in the fossil record.
Era
A cell that has complex internal structures, such as a nucleus; e.g., plant and animal cells.
Eukaryotic
Hadean Eon
Formation of the solar system.
The solar system developed during the:
Hadean Eon
Why do some people argue that the Cenozoic era should not be called the "Age of Mammals"?
Insects are equally as abundant during this era; birds are just as widespread as mammals during this era; and flowering plants are just as common during this era.
Paleozoic Era
Largest mass extinction in Earth's history.
What do scientists use to divide the geologic time scale?
Major divisions in the fossil records.
You wake up and find yourself surrounded by ferns, trees, flying birds, and different types of dinosaurs. Which era did you wake up in?
Mesozoic
Which of the following events define the Proterozoic eon?
Oxygen builds up in atmosphere; eukaryotic cells first seen; and stable continents.
The era that is defined by both a huge explosion in the diversity of life as well as the largest mass extinction is __________.
Paleozoic
Major divisions of geologic time within each era; identified by changes in the fossil record.
Period
A simple cell that lacks complex internal structures, e.g., bacterial cells.
Prokaryotic
Cenozoic Era
Sometimes called "Age of Mammals".
Fossil mounds made of ancient photosynthetic bacteria.
Stromatolites
Mesozoic Era
Time of the dinosaurs.
Archean Eon
Toxic atmosphere; first bacteria.