Fossils and Geologic Time

Flashcards covering key vocabulary related to fossils and geologic time.

Fossils

The preserved remains or evidence of an organism.

Fossil Record

A history of life on Earth represented by fossils that show changes in species over time.

Paleontology

The study of prehistoric life through the examination of fossils.

Trace Fossils

Fossils that reflect the activity or movement of an organism.

Mold Fossils

Fossils that create an empty space formed after the remains decay.

Cast Fossils

Fossils formed when a mold fills with minerals creating an exact copy.

Petrification

The process of organic material being replaced with minerals, turning it to stone.

Amber Fossils

Fossils found in hardened tree sap.

Relative Dating

Determining the age of fossils by their depth in sedimentary layers.

Radioactive Dating

Determining the precise age of fossils using the decay rate of radioactive isotopes.

Half-life

The time required for half of the radioactive atoms in a sample to decay.

Geologic Time Scale

A timeline of Earth's history divided into eras based on the fossil record.

Precambrian Era

The oldest geological era, lasting from about 4.6 billion to 550 million years ago.

Paleozoic Era

Geological era from 550 to 250 million years ago, characterized by the dominance of invertebrates.

Mesozoic Era

The age of reptiles and dinosaurs, lasting from 250 to 65 million years ago.

Cenozoic Era

The age of mammals, extending from 65 million years ago to the present.

Index Fossil

An easily recognized species used to compare the relative age of fossils.

Major Events of the Paleozoic Era

The emergence of vertebrates and significant plant life on land.

Oxygen Revolution

A major event during the Precambrian Era when oxygen levels significantly increased.