Evolution, that quintessential force driving life on earth, is also fraught with failures. Take for instance the fact that organisms need to adapt to new environments and for this, there must be enough genetic variation. Do we have those genes that can help us cope up with the copious changes we ourselves are exerting on the environment? If we cannot, then we’ll go extinct. But why does evolution not guarantee us those genes needed to survive?

This can be understood from a simple experiment. Take some bacteria in a test tube, cut short their sugar supply but crowd the tube with an alternative source that bacteria can’t consume at all. It is estimated that for the bacteria to digest that alternative source, it can take all up to 31,000 generations. So “just because a particular trait would be useful does not mean that it will soon evolve…if the environment continues to change as rapidly as it is at the moment — many creatures will fail to meet their evolve-by dates [the threshold doomsday dates].”