Here are some facts;
Offspring not only have genetic elements from their parents, but commonly have mutations which make them different from either, albeit subtly.
When a group are isolated from the rest of their species, the genetic drift can reach a point where if they are reunited, reproduction between groups can no longer viably occur.
Morphology changes over time/generations.
Where environmental pressures change or groups migrate over generations, morphological changes become more pronounced.
We find them all over the world. Preserved in various states in various places.
Rock layers exist.
These strata consist of various different materials, layered in a manner different from the gradation acquired from a settling of material in a solution due to mass of individual particles.
Radioactive isotopes decay.
These isotopes are found in many materials, such as the rock layers mentioned above. They decay at known rates producing “decay products” which can be measured.
Fossils are different in different strata.
The fossils from different layers, are markedly different.
Now here’s the controversial part..
The abundance of decay products in the differing rock layers and the morphological differences between otherwise similar fossils, correlate in the direction of time. With fossils from earlier layers becoming more similar and simpler.