By looking at a fossil record, a scientist can learn how a species developed over time. These fossils show what a species looked like in the past. Through testing, they can determine how old and what kind of organism it was so they can compare it to similar organism today to see how it evolved.
You could use the fossil record to help explain the evolution of a species by watching how it aged, what it ate, how it breed and where it lived along with a million of other things. It could have lived in the 20 below freezing and then you find that same fossil in the warmest place in the world it shows that the species either adapted or possibly had an offspring that could handle the high temperatures.
