Curated OER
Earth Epochs
Young scholars explore earth epochs, i.e, Permian, Precambrian, Cambrian, Ordivician and through pictures they see what life on Earth and animals looked like. They organize Earth Epochs according to years going from greatest to least...
University of California
Ucmp: The Paleozoic Era
An excellent overview of the Paleozoic Era. It also provides a chart where you can learn information regarding each of the time frames within the era.
University of California
Ucmp: Web Geological Time Machine
The Museum of Paleontology at Berkeley offers an online geological time machine which allows you to catch a glimpse of ancient eras in earth's history. Click into an "Era" to learn about its stratigraphy, life forms, localities, and...
University of California
Ucmp: Life During the Cambrian Period
Information about the life forms that were around during the Cambrian Period. Includes pictures of fossils and links to each life form type.
Other
Hvpm: Mass Extinctions
An overview of the mass extinctions throughout earth history. Each mass extinction has a link to its own page with a list of its possible causes and the species that were most affected.
Australian Museum
Australian Museum Society: Arthropods
A description of what arthropods actually are and a discussion of their origin, as well as some info on research.
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.
University of California
Ucmp: Annelids
Describes what segmented worms are and gives a brief description of thier evolution through the use of their fossil record.