Interpret several different types of evidence for evolutionary change -- fossils, comparative anatomy, direct observation, and DNA similarity -- as independent lines of evidence supporting the same pattern.
A natural history museum's evolution hall is really a collection of several different KINDS of evidence, each examined at its own exhibit station. This week is a virtual museum walk: look up images or a virtual tour online (a search for "whale evolution fossils" or "Darwin's finches Galapagos" works well) and treat each set of images like an exhibit card, asking what type of evidence it represents and what it suggests.
The main evidence types are: fossils (the whale sequence from two weeks ago), comparative anatomy (similar underlying bone patterns in very different species, such as the same basic set of bones arranged differently in a human arm, a bat wing, and a whale flipper, suggesting they share a common ancestor), direct observation of a population changing over recorded time (the peppered moths, or Darwin's finches on the Galapagos Islands), and, as a newer additional line of evidence, DNA similarity between species. One especially famous exhibit-worthy case is Darwin's finches: several finch species on different Galapagos islands, each with a differently shaped beak suited to a different food source, are now understood to have descended from one common ancestor finch species -- a pattern called adaptive radiation, where one ancestor gives rise to many specialized descendants.
Mastery looks like: They can identify the type of evidence a given example represents and explain why multiple independent lines of evidence strengthen a scientific conclusion.
Common stumbles: Treating fossils as the only evidence for evolutionary change; describing adaptive radiation as if each finch species chose its own beak shape rather than being shaped by generations of natural selection.