The fossil evidence for evolution long ago accumulated to the point of being totally conclusive. That said, even more has been uncovered recently, and is it fascinating! Via ScienceDaily:
“There are a couple of key features that make a turtle a turtle: its shell, for one, but also its toothless beak. A newly-discovered fossil turtle that lived 228 million years ago is shedding light on how modern turtles developed these traits. It had a beak, but while its body was Frisbee-shaped, its wide ribs hadn’t grown to form a shell like we see in turtles today.” (Link)
Another fascinating transition has also been uncovered, this one involving transitional root fossils in plants. Professor Dolan (who was involved in this research) remarked “I really want to find out where root caps came from. They seemed to have appeared out of thin air. They are very important in extant roots; the root cap is important to protect the root as it pushes through the soil and it is the site where roots detect gravity. How did these ancient roots manage without a cap to provide these functions?”
The answer: “The fossil analysis reveals that the meristems of A. mackiei lack both root hairs and caps — they are covered instead by a continuous layer of surface tissue. This structure makes these roots unique among the vascular plants.” (Link)
