Earth and Science Flashcards
is a record of life forms and geologic events in Earth’s history.
Geological Time Scale
Sometimes it is possible to distinguish layers of rock that formed during a single year or season.
Dividing Geological Time
thick stacks of rock that have no fossils provide little information that could help in subdividing geologic time.
Dividing Geological Time
A record of how Earth and its life forms have changed through time. For example, the scale shows when life first appeared on Earth.
Geological Time Scale
In the geologic time scale, time is divided into bigger blocks than years or centuries. The scale begins when Earth formed __________ years ago and goes to the present.
4.6 billion years ago
The geologic time scale is divided into (4)
Eons, Eras, Periods, and Epochs
TRUE OR FALSE
divisions of the geologic time scale have no fixed lengths.
TRUE
changes or events recorded in
Rocks and Fossils
The largest unit of time
Eon
is an extremely long, indefinite period of time.
Eon
Earth’s 4.6-billion-year history is divided into 4
Precambrian, Paleozoic, Mesozoic, Cenozoic
Paleozoic is divided into __ periods.
6 periods
The _________ Period is important because it is the first period after Precambrian Time.
Cambrian Period
The periods of the Cenozoic, the most recent era, are further divided into _______
Ephocs
Present day Earth is in the _________ era and the Quaternary period in the Holocene epoch.
Cenozoic Era
Geologic time has NOT Ended!
TRUE
Humans First Appeared
Pleistocene
Explosion of life
Cambrian Period
Age of man
Quaternary Period
no plants or animals existed, and multicellular organisms develop
Precambrian Period
LIFE EXPLODES! At the beginning of the ____________, all life lived in the oceans.
Paleozoic Era
Early invertebrates developed and later reptiles became dominant on land.
Paleozoic Era
Early plant included simple mosses, ferns, and cone-bearing plants.
Paleozoic Era
(Age of the Reptile/Dinosaurs
Dinosaurs lived along with the first mammals, birds, and flowering plants.
Mesozoic Era
Reptiles were dominant.
Mesozoic Era
The diversity of life forms increased.
Cenozoic Era
New mammals and birds appeared while other became extinct.
Cenozoic Era
Flowering plants became most common.
Cenozoic Era
Geologic time is divided into units based on
Rocks and Fossils
Precambrian Time
4.6 billion years ago
Paleozoic Era
544 million years ago
Mesozoic Era
225 and 65 million years ago
Cenozoic Era
65 million years ago to present day
