How could an impact of a meteorite lead to a mass extinction?

Answer 1

As the asteroid enters the atmosphere, most of the asteroid burns up, super heating the hunk o' rock, so that when it comes in contact with the surface, it drastically changes the climate of the surface, something not many animals can survive. Even if they survive, the smoke will kill most of the survivors anyway. But, most of the aquatic animals will survive.

Answer 2

When the asteroid hit Earth, it would have thrown enough dust into the upper atmosphere to block sunlight for months at a time. Without sunlight, the plants would die. Without plants, the herbivorous dinosaurs would die, and without them, the carnivores died out.

Answer 3

There are a few ways it could work.

1. One theory is cosmic winter (which is like a nuclear winter except precipitated by cosmic events). The asteroid blows tremendous amounts of material into the atmosphere. With little to no solar radiation reaching the ground, temperatures plummet and plants start suffering from lack of photosynthesis. Low temperatures and low food supply can make it difficult for anything to survive for however long it takes for the winter to finally blow over.
2. Another possibility is that this same dust could make it difficult to breathe (by getting into the lungs) or even to move around (by lodging into skin and other exterior tissues).
3. Impact (See the Related Links)

Answer 4

The impact causes an extremely large explosion which blasts vast quantities of dust into the atmosphere. This can act to block out or reduce the radiation reaching Earth from the sun.

This in turn effects the growth of plants which are in turn the food for other creatures and can lead to food shortages, starvation and extinction.

Answer 5

If the meteorite is large enough it would knock enough dust into the air to freeze the world. The dust could block out the sunlight.