Geologic Time Scale Part 1

Front

What is an index fossil?

Back

An index fossil is a fossil that is used to define and identify a particular time period in the geologic time scale. It is typically widespread, abundant, and existed for a relatively short duration.

Front

Which fossil is considered the best index fossil?

Back

Fossil 2 is considered the best index fossil as it meets the criteria of being widespread and having a short geological time range.

Front

How do rock layers typically form?

Back

Rock layers form horizontally due to the force of gravity.

Front

What is the oldest known organism on the geologic time scale?

Back

The oldest known organism on the geologic time scale is the trilobite.

Front

What is the most recent era of the geologic time scale?

Back

The most recent era is the Cenozoic era.

Front

What does radiometric dating allow scientists to determine?

Back

Radiometric dating allows scientists to determine the exact or absolute age of rock layers and the fossils within them.

Front

What is the difference between relative age and absolute age?

Back

Relative age is the age of an object in relation to other objects, while absolute age is the actual age of an object, often determined through radiometric dating.

Front

What are the four main eras of the geologic time scale?

Back

The four main eras are Precambrian, Paleozoic, Mesozoic, and Cenozoic.

Front

What is the significance of the Cenozoic era?

Back

The Cenozoic era is significant as it is the current era, marked by the rise of mammals and birds, and significant changes in climate and geography.

Front

What type of organisms dominated the Paleozoic era?

Back

The Paleozoic era was dominated by marine life, including fish, amphibians, and early reptiles.