The emergence of small mammals in daytime and survival rate due to adaptation with the existing environment was the reason for the subsequent emergence of mammals.
Step-by-step explanation:
The extinction of dinosaurs made mammals coming out in day light. Paleontologist believe that day time activities of mammals started after the dinosaurs disappeared 65 million years ago at the end of Crustaceous period.
When mammals survived the disaster which finished the dinosaurs. The small mammals like marsupials, insectivores became abundant on earth.
The fur bearing warm blooded mammals eventually evolved in human species.
The eating habits of small mammals left after extinction of dinosaur made them survive where no plant life was left.