Smithsonian Institution
National Museum of Natural History: Paleobiology: Geologic Time: The Oligocene
Travel through Earth's history to learn about the Oligocene time period, which is characterized by the appearance of most of the living families of mammals.
BBC
Bbc Nature: Prehistoric Life: Jurassic Period
Overview of the Earth in the Jurassic Period told by photos, news, videos, and external links with emphasis on what grew then, what lived then, the causes of mass extinction, types of fossils, and what life was like in general.
PBS
Pbs Learning Media: The Wall of Time
This illustrated timeline from the Lunar and Planetary Institute provides a journey through four-and-a-half billion years of time from the birth of our solar system to its current existence today.
Estrella Mountain Community College
Online Biology Book: Paleobiology: The Late Paleozoic
College-level biology book covers the Late Paleozoic geologic time period in Earth's history. See photographs of fossil evidence from that era in addition to diagrams to help with understanding.
PBS
Nova: A Brief History of Earth
This timeline is a good resource if you are looking for brief descriptions of the geologic periods. Descriptions include pictures of common organisms for each period and the range of time covered by each period.
BBC
Bbc Nature: Prehistoric Life: Irish Elk
Examine the enthralling world of the Irish elk by uncovering details about its behaviors, habitats, geological time periods, and classification through photos, a video, descriptions, and external links.
Other
Georgia Perimeter College: The Permian Period
This resource provides basic information of the changes that took place during the Permian period as well as the animals that populated the Earth during this time.
Sophia Learning
Sophia: Mesozoic Era
Learn the basic information about the Mesozoic Era in Earth's geologic history.
Sophia Learning
Sophia: Paleozoic Era
A brief overview illustrating the Paleozoic era in Earth's geologic history.
BBC
Bbc Nature: Prehistoric Life
Explore life on ancient Earth with this site! Students can walk with dinosaurs to see what Earth looked like or investigate Earth's history. The site includes articles, pictures, timelines, and lots more.
Other
Georgia Perimeter College: The Precambrian Era
This resource provides detailed information on each of the periods within the Precambrian Era. It discusses what earth was like, what the first multiple cell organisms were like and when they appeared.
University of California
Ucmp: The Museum of Paleontology
This site contains on-line exhibits including animals, plants, time periods, phylogeny, geology, and evolution. Also, a search is provided at the bottom of the site for more specific information.