Answer
The demise of the large Mesozoic reptiles, particularly the non-avian dinosaurs, created an ecological opportunity for the development of mammals. After the mass extinction event at the end of the Cretaceous period, many ecological niches were left vacant due to the extinction of dominant reptilian species. Mammals, which were relatively small and had been living in the shadows of the dinosaurs, were able to exploit these vacant niches and undergo rapid diversification.
With reduced competition from the large reptiles, mammals had the chance to occupy various ecological roles and adapt to different habitats. This led to the evolutionary radiation of mammals during the early Cenozoic era. They diversified in terms of body size, feeding strategies, and locomotion, leading to the development of various mammalian groups, including primates, which eventually gave rise to our ancestors.
Work Step by Step
Refer to the answer above.
