Intro to Geologic Time

a record of geologic events and the evolution of lifeforms as shown in the fossil record

the divisions of this scale are used to date events in Earth's History

begins when the Earth was formed and goes on until the present

The earliest time span of Earth's History

Begins with early invertebrates - Trilobites and Brachiopods; continued developed vertebrate fish, then arachnids and insects; later came the first amphibians, and near the end of the Era Reptiles became dominant.

Early land plants includes simple mosses, ferns, and cone bearing plants, and by the end of the Era, seed plants were common.

The mass extinction that ended this Era caused marine invertebrates as well as amphibians to disappear.

Formation of Pangaea.

Reptiles were dominant including various dinosaurs.

Small mammals and birds appeared.

Toward the end of the era, flowering plants appeared and the kinds of mammals increased.

The mass extinction that ended the era caused the Dinosaurs to become extinct.

A major geologic event of this Era was the break up of Pangaea.

New mammals appeared while others became extinct.

The diversity of life forms increased.

Flowering plants became most common.

Humans are also part of the most recent period of this era.

Present day earth is in this era.

A major geologic event of the Cenozoic Era is the further splitting and moving of continents to their current positions.