Geologic Time Scale

Front

______________ is the long span of time that begins geologic time.

Back

Precambrian Time

Front

A unit of geologic time that subdivides eras

Back

period

Front

The Triassic Period, the Jurassic Period, and the Cretaceous Period occurred in what era?

Back

Mesozoic

Front

_______ for many of the geologic periods come from places around the world where geologists first described the rocks and fossils of the period.

Back

names

Front

Scientists chose where units of geologic time began on major changes in ______________ at certain times.

Back

life forms

Front

Scientists divided the time between Precambrian Time and the present into three units of time, or eras.

Back

True

Front

To develop the geologic time scale, scientists studied rock layers and fossils from the different eras.

Back

False

Front

Eras are subdivided into units of geologic time called periods.

Back

True

Front

___________ a record of the geologic events and the evolution of life forms as shown in the fossil record.

Back

Geologic Time Scale

Front

The Quaternary period, where humans first appeared, is in the Mesozoic era.

Back

False