Geologic Time Periods
This is the longest unit of geologic time.
What is an eon?
This period took up roughly 90% of Earth's history.
What is Precambrian time?
True or False: Precambrian and Paleozoic Earth looked very similar to Earth today.
What is FALSE! Earth was very different then.
What is the age of invertebrates.
What is the middle Paleozoic called?
What is the age of fishes?
What are the geologic time periods, from largest to smallest?
What are eons, eras, periods, and epochs?
In which epoch do we currently live?
What is the Holocene epoch?
This was the sudden appearance of new multicellular organisms with hard parts about 542 mya.
What is the Cambrian Explosion?
What is an invertebrate?
What is an animal with no backbone?
What kind of animals appeared during the middle Paleozoic?
What are vertebrates (animals with backbones)?
In which eon do we currently live?
What is the Phanerozoic Eon?
What were the organisms like during the Precambrian time?
Organisms simple, unicellular, and soft-bodied; they went extinct at the end of the Precambrian period.
What are the time unit boundaries on the geologic time scale based on?
The different boundaries are based on different fossils in the rock layers.
What was the climate like during the early Paleozoic?
The climate was warm.
Aside from vertebrates, what 2 other things of importance happened during the middle Paleozoic?
(1). plants first appeared
(2) continents collided
In which era do we currently live?
What is the Cenozoic Era?
What is TRUE.
TRUE OR FALSE: All of the time units in the geologic time scale are of the same length.
Where were the invertebrates located during the early Paleozoic?
The invertebrates were in the ocean; there was also. shallow inland seas on continents.
What mountain range formed during the middle Paleozoic?
What are the Appalachian Mountains?
In which period do we currently live?
What is the Quaternary Epoch?
What 2 things affect the evolution of a species?
What are (1) environmental changes and
(2) slow movement of tectonic plates
What was significant about the Cambrian explosion?
Because new , more complex organisms developed (that contained hard parts), they could be more easily preserved as fossils.
What happened at the end of the early Paleozoic?
The second largest mass extinction in Earth's history ended the early Paleozoic.
What ended the middle Paleozoic?
A mass extinction.