Paleontological evidence of evolution
Although the fossil record is often incomplete, either because they were not fossilized, they have not been preserved, or because they have not yet been found, in some cases it has been possible to reconstruct their phylogeny. That is, complete series, ordered from oldest to most modern species.
Studying the fossils it is possible to observe how some species have transformed into others. It is even possible to reconstruct how they adapted to the new environmental conditions of the environment.
Some fossils, transitional fossils, are intermediate forms between two groups of living things. For example, the Archaeopterys has typical characteristics of reptiles (tail and teeth) and of birds (feathers), which would show that current birds evolved from some reptiles.