Scientists study the fossil records of extinct organisms and compare them with modern organisms to identify similarities and differences. By examining the preserved remains of ancient organisms, researchers can infer evolutionary relationships. For example, the Archaeopteryx, shown above as a fossil and as a model created from the fossil, exhibits both bird and reptile characteristics.

Archaeopteryx has bird-like characteristics such as
, and reptile characteristics such as . This the evolutionary link between dinosaurs and modern birds.

feathers and wings, but also has teeth and a long bony tail. This fossil provides evidence for the evolutionary link between dinosaurs and modern birds. By studying fossils like Archaeopteryx, scientists can better understand how different species have evolved over time and how modern organisms are related to those that lived in the past.