WE thank Dawn for sharing information about the new research towards a common ancestor for all mammals: a prehistoric rat-sized animal (Feb 10).

The two interlinked studies also tell us that how a giant asteroid collided with our tiny blue planet about 65 million years back as a result of which most of the large creatures, especially dinosaurs, were wiped out from the pages of evolutionary biology, thus paving the way for smaller beings to emerge in this never ending drama of survival of the fittest.

This enormous collision might have brought drastic changes to the environment, ecosystem and habitat of its population. A vast cloud of dust and smoke might have blocked sunlight for very many years to reach the planet making living conditions hostile and unfavourable for different life forms.

In my opinion, apart from this cosmic phenomenon, other factors including the spread of some highly contagious infection amongst dinosaurs, their inability to protect their eggs and newborns from predators and natural calamities and even domination of a particular flesh-eating species might be other contributing factors towards the sudden and tragic extinction of these giants.

As regards researchers’ opinion that the tragedy for dinosaurs has provided an opportunity for smaller mammals to thrive and survive, it sounds realistic as it is the basic principle of evolution of species.

Apart from extinction of dinosaurs, the impact of a large-sized asteroid collision might have resulted in some minor tilt in the earth’s orbit around the sun, resulting in better climatic conditions and opportunities for the next generation of species to survive.

DR HASAN FAISAL Islamabad