Chapter 4: A Trip Through Geologic Time

Which type of fossil is this?

This era is known as "Old Life"

The age of a rock given as the number of years since the rock formed.

A type of fossil that provides evidence of the activities of ancient organisms.

Which rock layer is oldest?

The law that says that the older layers or rock are below the younger layers.

One of the units of geologic time into which geologists divide eras.

A record of the geologic events and life forms in Earth's history.

An igneous intrusion rock is ________________ than the rock it cuts through.

A break in Earth's crust along which rocks move.

Fossils of widely distributed organisms that lived during a geologically short period.

An igneous rock layer formed when magma hardens beneath Earth's surface.

Which type of fossil is this?

One of the four long units of geologic time (such as the Precambrian)

The preserved remains or traces of an organism that lived in the past.

Term used to refer to a group of related organisms that has died out and has no living members.

Change over time; the process by which modern organisms have descended from ancient organisms.

An igneous rock layer formed when lava flows onto Earth's surface and hardens.

A fossil that is a solid copy of an organism's shape, formed when minerals seep into a mold.

Which era do we currently live in?

Which rock layer is youngest?

A scientist who studies fossils to learn about organisms that lived long ago.

The age of a rock compared to the ages of other rocks.

This Era is known as the "age of reptiles".

A fossil in which minerals replace all or part of an organism.

A type of fossil consisting of extremely thin coating of carbon on rock.

A type of fossil that is a hollow area in sediment in the shape of an organism or part.

A gap in the geologic record that shows where rock layers have been lost due to erosion.

Which Era ended when a meteor hitting the Earth changed the climate?

Era that started with a huge explosion of different life forms

This was the era the earth spent 88% of it's history in