Final answer:
Students use the law of superposition and faunal succession to determine the relative ages of fossils, which helps them construct the chronological sequence of evolution and calculate the rate of speciation.
Step-by-step explanation:
Relative Dating Techniques and Fossils
To determine the relative ages of fossilized organisms, students would apply the principle of superposition. This principle, established by Nicolas Steno, posits that in a sequence of undisturbed sedimentary layers or strata, the oldest layer is at the bottom and the layers get progressively younger as you move to the top. Therefore, fossils found at lower layers are typically older than those found in upper layers.
By examining the rock layers and the fossils within, students can infer the chronological sequence of organismal evolution and speciation. The transition from simple to complex organisms, and the emergence or disappearance of certain species, can be mapped out. Additionally, students might employ the concept of faunal succession, which is the observation that fossil groups follow a particular vertical order within the strata. Therefore, specific fossils known as index fossils, which are widespread geographically and limited to a short span of geological time, can be used to identify the relative age of the layers in which they are found.
By piecing together these observations and laws, students can construct a fossil record which provides insights into the history of life on Earth and the timing of evolutionary events, aiding in calculating the rate of speciation of early organisms.