Divisions of Time
Eras are broken down into which division of geological time.
Periods
The first life forms on earth lived here.
The Ocean/ Sea
It is much easier to contemplate Earths history when you scale it down into a ________ hour clock.
24
This period marks the end of the age or reptiles as well as the Mesozoic Era and is named for the limestone that was laid down during it.
Cretaceous
Dinosaurs ruled the earth during this Era
Mesozoic
Periods are broken down into this division of geological time.
Epochs
This is the era when Mammals rule the earth.
Cenozoic
The earth is this old.
4.5-4.6 billion years old
The age of reptiles begins
Triassic
Named for the Jura mountains in France, This period is in the middle of the Mesozoic.
Jurassic
We are currently in which era?
Cenozoic
This is when the majority of species is wiped out in a single event.
Mass Extinction
According to the 24 hour geo-time scale, humans don't appear until when?
The Last Second
We are currently in this period
Quaternary
This mass extinction marked the end of the Mesozoic and the beginning of the Cenozoic
The K/T Extinction (Asteroid)
The Eon in which the Earth we know now is still forming and resembles a fiery underworld.
Hadean
The first vertebrates evolved in this era
Paleozoic
The geological time scale is a record of...
Life forms and geological events.
In both the asteroid-impact and volcanic eruption extinction theories what really wiped out the majority of species?
Large clouds covered the sky/ sun
Life began to be more complex during the beginning of the Paleozoic era this many years ago
544 Million Years
Geologic time begins with a large chunk of time when simple invertebrates thrived.
Precambrian Time
Great "explosion" of invertebrate life occurs in seas
Cambrian
This extinction marked the end of the Paleozoic and the beginning of Mesozoic
Permian Extinction
Anthropocene
First amphibians reach land in during this period
Devonian
According to the 24 hour geo-time scale dinosaurs appear at this time and rule the earth for this long
11:00 p.m. / 30 mins
The first fish developed jaw bones
Silurian