The diagram below represents a section of undisturbed layers of sedimentary rocks. It shows the location of fossils of several closely related species. According to currently accepted evolutionary theory, which is the most probable assumption about species A, B, and C?
Species C existed before species B
Following conclusions can be drawn by observing the figure.
1. Species A is the most recent species because it is located on top.
2. Species B is more abundant than species C as its fossils are found in two layers of the sedimentary rock.
3. Deeper the layers, older are the fossils. So, fossils of species C are older than the fossils of species B. Thus, species C existed before species B.
Different layers of earth provide information about geological time scale. Scientists link the fossils and the geological time scale information to know the time of existence of those species.