Geologic Time Line

Geologic time is divided into units based on ______.

The end of most Eras are marked by a major catastrophe causing mass ____________.  

Life-forms that first appeared in the Cenozoic Era include ______.

During which geologic period did earliest reptiles and the great coal-forming forests exist?

A fossil of a dinosaur would probably be from the ___.

Theoretically, how old is the Earth?

Plate tectonics may affect changes in species because movement of plates causes a change in:

On the GTS, where did life first appear on Earth?

What three fossils would be representative of the Devonian Period?

According to the table, which geologic time period occurred more than 800 million years ago?

Large mammals, megafauna of the Cenozoic Era may have become extinct because of activity of:

The Hadean, Archean and Proterozoic Eons are usually grouped into a 'super eon' called the:

In K-T Boundary, they found rocks that form only when melted under sudden intense heat called

What is the current geologic era called?

The Paleozoic Era ended in what possible event that caused 95% mass extinction of marine life?

Humans appeared in the ______ Era.

How does the Geologic Time Scale describe the early Earth?

From evidence, the extinction event that put an end to the dinosaurs is believed to have been:

Where are most of the events along the geologic timeline?

What is absolute dating?

The Precambrian was when the Earth was still settling and takes up about what % of GTL?

Amber, which often preserved whole insects and found in rocks is:

Which Era includes the Jurassic period?

The largest divisions in geologic time are ______.

What is the Geologic Time Scale?

The oldest rock on Earth formed during the _______________.

According to the GTL, dinosaurs disappeared from fossil record how many years ago?

Finding the approximate rock age based on the oldest rock being on the bottom is called

What Are Trace Fossils?

The era of middle life; a time of many changes on Earth.

As __ evolved, they grew into stromatolites and changed Earth’s atmosphere by producing oxygen:

During which geologic period did the Cascades, Alps, and Himalayas form?

The trilobite is considered to be the most famous:

As climates changed, organisms that could adapt survived, others became extinct:

In GTS, the first living organism in the fossil record is called

The first vertebrates were fish. In which period did they first appear?

Precambrian time began with __________.