This is called relative age dating, the first step.Next, evolutionary scientists then use to help establish the relative ages of rock layers that are not directly related to one another and their fossils.However, as you will soon learn, these techniques stray far from absolute dates, though they may reveal relative ages of some rocks.
The principle of uniformity is a philosophy and an assumption that the slow geologic processes going on today must explain the deposits of the past.
They teach the motto, “the present is the key to the past.” It’s not.
If that had happened, Darwin’s ideas would have been refuted and abandoned.
Instead, radioactive dating indicates that Earth is about 4.5 billion years old—plenty of time for evolution and natural selection to take place.[i] But as we show here, geologists do not use radioactivity to establish the age of certain rocks.
As any judge in court will attest, eyewitness records record the past more accurately.
Also, keen observations in the field testify that the sediments comprising the ancient rock layers were laid down , not slowly over millions of years.
Index fossils are distinct fossils, usually of an extinct organism found in only one or a few layers, though that layer or layers outcrops in many places—at least that’s the theory.
They help establish and correlate the relative ages of rock layers.
High school biology books openly acknowledge this necessary connection: Evolution takes a long time. Geologists now use radioactivity to establish the age of certain rocks and fossils.
This kind of data could have shown that the Earth is young.
After all, plenty of assumptions go into the calculations, as we’ll discuss in this chapter.