Layers are laid down on top of each other, with the bottom layers laid down first and the top layers laid down last; therefore, the layers on the bottom are the oldest and the ones on the top are the youngest.
Please feel free to refine this list and repost it, just please preserve the photo credits and links to photographers.
Also, suggestions for improvement on any items is welcome as this is a lot of material over a wide range of scientific fields, so I have certainly bungled some things here.
Jump To: Age of the Earth and Its Fossils Genetics Comparative Anatomy Transitional Fossils Convergent Evolution Adaptations Vestigial Traits Artificial Selection Evolution in Action Sexual Selection And The List Goes On…
These reasons will work from the general to the specific.
Cynognathus, a Triassic land reptile, fossils are found in South America and Africa.