What is relative and absolute dating
Information about Simon Winchester's delightful biography of Smith, The Map That Changed the World is available at Tree-Ring dating is based on the principle that the growth rings on certain species of trees reflect variations in seasonal and annual rainfall.
Trees from the same species, growing in the same area or environment will be exposed to the same conditions, and hence their growth rings will match at the point where their lifecycles overlap.
There, you will find a brief description of the method, plus links to take you to other webpages with more extensive information.
Dating is not necessary to demonstrate that evolution is a fact.
These tests have been performed on what are thought to be the earth's oldest surviving rocks, meteorites, and moon rocks.
These tests have consistently given the same ages for each of these objects.
Chronological sequence is all that is really required.
However, human beings love to see factual precision, and we want to know how old something is.
[ While this may be true, a shrub in Tasmania could be 40,000 years old.A specialized form of cross-dating, using animal and plant fossils, is known as biostratigraphy.Keyed to the relative time scale are examples of index fossils, the forms of life which existed during limited periods of geologic time and thus are used as guides to the age of the rocks in which they are preserved.Be sure to see An Animated Isochron Diagram, or, Watching a Rock Age on an Isochron Diagram. Radiometric Dating from The Evolution Evidence Page.The most compelling argument for an age of the earth of 4.5 billion years are the large number of independent tests that have been used to confirm this date.