*Life Science: Fossils indicate that many organisms that lived long ago are extinct.
Extinction of species is common; most of the species that have lived on the earth no longer exist.
This relative time scale divides the vast amount of earth history into various sections based on geological events (sea encroachments, mountain-building, and depositional events), and notable biological events (appearance, relative abundance, or extinction of certain life forms).
The fossils represented by the letters on this card are "younger" than the "T" or "C" fossils on the "TC" card which represents fossils in the oldest rock layer.
Sequence the remaining cards by using the same process.
*Earth and Space Science: Fossils provide important evidence of how life and environmental conditions have changed.
The complete "Paleontology and Dinosaurs" module takes approximately four weeks to teach. " activity is a 30-minute introduction to geologic time.
Scientists also use direct evidence from observations of the rock layers themselves to help determine the relative age of rock layers.