Question

How the mass extension of the dinosaurs affected the evolution of Mammals. The answer should be the language of evolutionary theory and should mention “punctuated equilibrium” as the part of explanation.
The assignment is for atleast 45 marks.

Answer 1

Solution

• When dinosaurs went extinct, a lot of competitors and predators of mammals disappeared, meaning that a great deal of the pressure limiting what mammals could do ecologically was removed.
• They clearly took advantage of that opportunity, as we can see by their rapid increases in body size and ecological diversity.
• Mammals evolved a greater variety of forms in the first few million years after the dinosaurs went extinct than in the previous 160 million years of mammal evolution under the rule of dinosaurs.
• The mass extinction that wiped out the dinosaurs 66 million years ago is traditionally acknowledged as the start of the 'Age of Mammals' because several types of mammal appear for the first time immediately afterwards.
• The earliest placental mammal fossils appear only a few hundred thousand years after the mass extinction, suggesting the event played a key role in diversification of the mammal group to which we belong.
• So there is a burst of evolution into new forms, followed by specialisation that finally resulted in the groups of mammals we see today in the world.