Locally, physical characteristics of rocks can be compared and correlated.

On a larger scale, even between continents, fossil evidence can help in correlating rock layers.

examples of relative dating and absolute dating-84

This would also mean that fossils found in the deepest layer of rocks in an area would represent the oldest forms of life in that particular rock formation.

In reading earth history, these layers would be "read" from bottom to top or oldest to most recent.

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.

*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.Scientists also use direct evidence from observations of the rock layers themselves to help determine the relative age of rock layers.Specific rock formations are indicative of a particular type of environment existing when the rock was being formed.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).Objectives: When you complete this activity, you will be able to: (1) sequence information using items which overlap specific sets; (2) relate sequencing to the Law of Superposition; and (3) show how fossils can be used to give relative dates to rock layers.INTRODUCTION Scientists have good evidence that the earth is very old, approximately four and one-half billion years old.