Bullis Science- Fossils and Paleontology

Catastrophism
Catastrophism
Principle that states that geologic change is caused by very sudden and rare events.

Uniformitarianism
Uniformitarianism
Principle that states that geologic change is slow and constant. Processes that occured in the past are still happening today.

K-T Mass Extinction
K-T Mass Extinction
An example of catastrophism that resulted from an asteroid hitting the earth 65 mya.

Paleontology
Paleontology
The study of Earth’s past through fossils.

Principle of Superposition
Principle of Superposition
The geologic principle that states that in layers of sedimentary rock, each layer is older than the layers above it and younger than the layer below it.

Relative Age
Relative Age
The age of a rock compared to the ages of rock layers

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

Half-Life
The time it takes for half of the atoms of a radioactive element to decay.

Rock A is older than Rock B but younger than Rock C. Is this an example of absolute age or relative age?
Relative Age

You find a rock that is 4380 years old. Is this an example of absolute age or relative age?
Absolute Age

Fossil
Fossil
The preserved remains or traces of once living things

Trace Fossil
Trace Fossil
A type of fossil that provides evidence of the activities of ancient organisms

Mold
Mold
An impression left by the organism.

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

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

Amber
Amber
Fossil that forms when tree sap traps small organisms and then hardens. Preserves entire organism.

Ice
Fossil that forms when organism is frozen. Can preserve soft tissue (hair, skin, etc).

Asphalt
Asphalt
Fossil that forms when organism falls into tar pits and the tar turns to asphalt. Good example=La Brea Tar Pits in L.A.

Index Fossil
Index Fossil
Fossils of widely distributed organisms that lived during only one short period.

Importance of studying fossils
Importance of studying fossils
1. To see how LIFE on earth has changed.
2. To see how the ENVIRONMENT has changed.