Many evolutionary biologists traditionally held that early mammalian diversification was strictly constrained by the ecological dominance of dinosaurs, occurring in earnest only after the end-Cretaceous mass extinction. According to this traditional view, Mesozoic mammals remained small, nocturnal, and functionally unspecialized throughout the era, filling only marginal ecological niches.
However, recent discoveries of remarkably preserved Mesozoic mammalian fossils have challenged this long-standing narrative. High-resolution biomechanical analyses of these specimens reveal an impressive array of specialized dental and skeletal adaptations—including structural modifications for digging, swimming, and aerial gliding—demonstrating that Mesozoic mammals occupied diverse ecological roles long before the extinction of the dinosaurs.
Consequently, paleontologists are revising their understanding of early mammalian history. Rather than viewing the end-Cretaceous extinction as the initial trigger for mammalian adaptive variation, researchers now regard it as an event that expanded opportunities for lineages that had already established substantial morphological diversity.
Which of the following best describes the function of the second paragraph in the context of the passage as a whole?
- It provides recent empirical evidence that challenges the traditional viewpoint presented in the first paragraph.Answer
- BIt elaborates on the specific environmental causes of the mass extinction event mentioned in the opening paragraph.
- CIt states the ultimate conclusion and theoretical synthesis that paleontologists should adopt moving forward.
- DIt dismisses the new fossil findings as unrepresentative exceptions to an otherwise valid historical rule.
- EIt reconciles two opposing theoretical models by showing that both are partially correct.