In the article, Perkin begun by describing how the fossils can shed light of evolutionary changes. For example, the transitional fossil can provide how the ancestor and modern species are different and similar. The most known example of transitional fossil is Tiktaalik which is the species between the arthropod and tetrapod. In addition, we can trace back the ancestor of the modern species using fossils. In the article, Perkins details how the species named elder frog might be an ancestor of salamander and frog, which fundamentally means that salamander and frog might be related species. The scientists observe the physical characteristics of the elder frog such as the shoulder, shape, and toes to infer how the animals might be related to each
