What are the dynamics and the impact consequences of X-ray super-flares on Earth’s atmosphere and life?

The X-ray and Gamma radiations, which are both pretty much the same, are very high energy electromagnetic radiation. Besides the X-ray machine they are produced by very hot bodies like stars. They are produced by both yang and older stars.

“In stars like our sun, X-ray flares are produced by the hot outer surface, or corona, of the star. The intensity of the X-rays produced is dependant on a number of factors including the star’s age and rotation. Using Chandra, researchers have found “violent” stars that tend to produce flares one hundred times more powerful than those produced by more docile stars. When these super-flares strike the planet-forming disks that surround the star, they can alter the positions of any nascent planets.” http://www.jyi.org/articletools/print.php?id=223

I think this what you were after.

“The scientists calculated that gamma-ray radiation from a relatively nearby star explosion, hitting the Earth for only ten seconds, could deplete up to half of the atmosphere's protective ozone layer. Recovery could take at least five years. With the ozone layer damaged, ultraviolet radiation from the Sun could kill much of the life on land and near the surface of oceans and lakes, and disrupt the food chain.”

SS

A higher mutation rate will occur over time. Evolution may be effected. If any radiation exposure was high enough for a long enough duration then the possibility of all life coming to an end is a possibility! But that would be remote unless you encounter extremely high exposure rates then even a brief duration will kill even the lifeforms deeply rooted as well,thus leaving nothing to continue on in any form.