Busy. Please wait.

show password
Forgot Password?

Don't have an account?  Sign up 

Username is available taken
show password


Make sure to remember your password. If you forget it there is no way for StudyStack to send you a reset link. You would need to create a new account.
We do not share your email address with others. It is only used to allow you to reset your password. For details read our Privacy Policy and Terms of Service.

Already a StudyStack user? Log In

Reset Password
Enter the associated with your account, and we'll email you a link to reset your password.
Don't know
remaining cards
To flip the current card, click it or press the Spacebar key.  To move the current card to one of the three colored boxes, click on the box.  You may also press the UP ARROW key to move the card to the "Know" box, the DOWN ARROW key to move the card to the "Don't know" box, or the RIGHT ARROW key to move the card to the Remaining box.  You may also click on the card displayed in any of the three boxes to bring that card back to the center.

Pass complete!

"Know" box contains:
Time elapsed:
restart all cards
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.

  Normal Size     Small Size show me how

Chapter 12

A Trip Through Geologic Time

Question Answer
Fossil The reserved remains or traces of an organism that lived in the past.
Mold A type pf fossil that is hollow area in sediment in the shape of an organism or part of an organism.
Cast A fossil that is a solid copy of an organism's shape, formed when minerals seep into a mold.
Petrified Fossil A fossil in which minerals replace all or part of an organism.
Carbon Film A type of fossil consisting of an extremely thin coating of carbon on rock.
Trace Fossil A type of fossil that provides evidence or the activities of ancient organisms.
Paleontologist A scientist who studies fossils to learn about organisms that live long ago.
Evolution Change over time; the process by which modern organisms have descended from ancient organisms.
Extinct Term used to refer to a group of related organisms that has died out and has no living members.
Relative Age The age of a rock compared to the ages of other rocks.
Absolute Age The age of a rock given as the number of years since the rock formed.
Geologic Time Scale A record of the geologic events and life forms in Earth's history.
Era One of the three long units of geologic time between the Precambrian and the present.
Period One of the units of geologic time into which geologists divide eras.
Invertebrate An animal without a backbone.
Vertebrate An animal with a backbone.
Amphibian A vertebrate whose body temperature is determined by the temperature of its environment, and that lives its early life in water and its adult life on land.
Law of Superposition The geologic principle that states that in horizontal layers of sedimentary rock, each layer is older that the layer above it and younger than the layer below it.
Extrustion An igneous rock layer formed when lave flows on Earth's surface and hardens.
Fault A break in Earth's crust along which rock moves.
Index Fossil Fossils of widely distributed organisms that lived during a geologically short period.
Unconformity A gap in the geologic record that shows where rock layers have been lost due to erosion.
Created by: creedenb