As these changes have occurred, organisms have evolved, and remnants of some have been preserved as fossils.
A fossil can be studied to determine what kind of organism it represents, how the organism lived, and how it was preserved.
Some critics, particularly religious fundamentalists, argue that neither fossils nor dating can be trusted, and that their interpretations are better.
Other critics, perhaps more familiar with the data, question certain aspects of the quality of the fossil record and of its dating.
The method most commonly used in archaeology is carbon dating.
Instead, other methods are used to work out a fossil’s age.
Early geologists, in the 1700s and 1800s, noticed how fossils seemed to occur in sequences: certain assemblages of fossils were always found below other assemblages. Since 1859, paleontologists, or fossil experts, have searched the world for fossils.
These skeptics do not provide scientific evidence for their views.
Current understanding of the history of life is probably close to the truth because it is based on repeated and careful testing and consideration of data.
In carbon dating, scientists look at how much carbon is left in the fossil, look at the half-life period, and use that to see when it was from.
Our understanding of the shape and pattern of the history of life depends on the accuracy of fossils and dating methods.