Geological Time Scale

Cenozoic Era

Also known as the Age of Mammals.

True Form Fossils

A type of fossil where the whole organism is preserved without being altered.

True Form Fossils (Where Found)

Trapped in ice, tar, or amber (sap).

Mesozoic Era

Also known as the Age of the Reptiles.

Trace Fossils

A fossil that gives evidence of life but is not the remains of an organism.

Trace Fossils (Examples)

Footprints, burrows, and coprolite.

Trace Fossils (Used to Study)

Animal behavior, how animals moved, etc.

Evolution

The process of changing over time or generations as an organism adapts to its environment.

Fossil Formation

Fossils are most likely to form underwater.

Carbon Film Fossils

A fossil where carbon residue leaves an outline of an organism on a rock through carbonization.

Fossil Record

Evidence about the history of life on Earth and how different types of organisms have changed over time.

Geological Time Scale

Shows the span of Earth's history over the last 4.5 billion years.

Middle Era

Mesozoic.

Oldest Era

Precambrian.

Increase in Diversity

During the Paleozoic Era, a huge increase in the diversity of multicellular organisms was called the Cambrian Explosion.

Mass Extinction

During the Paleozoic Era, a mass extinction wiped out 90% of all marine life.

Continental Movement

During the Mesozoic Era, continents began moving from the supercontinent Pangaea.

Mammals in the Cenozoic Era

Mammals became abundant because of the absence of reptiles.

Pressure and Heat

Help form carbon film fossils.

Mold Fossils

Fossils left behind after an organism has been dissolved away.

Cast Fossils

Fossils that show a 3D form sticking out.

Making a Cast

Plaster can be used to make a 2D or 3D cast from a mold fossil.

Cast Fossil Formation

After an organism dies, minerals seep into the mold it leaves and form a cast fossil.

Marine Organisms

Disappeared from certain areas because landforms occurred.

Phanerozoic Eon

Includes the Cenozoic, Mesozoic, and Paleozoic eras. Precambrian is older and is not part of the Phanerozoic Eon.