According to the dominant islamic position, evil is only associated with freewill. Animals act instinctually, without an ability for abstract reasoning. Even the most intelligent animal is less capable to think abstractly than a mentally handicapped human. Humans on the other hand have been entrusted with two "unique" qualities - abstract thought (we can simply say intellect) and the ability to make choices based upon that (we can say freewill). For an act to be evil, again, according to Islamic beliefs, there must be these two factors.
Due to this, we would not consider the acts of an animal or an insane person, someone who acts unconsciously or someone who is coerced as being evil.
As for what occurs in the world, I do not agree that they are random. I believe they occur due to outlet and inner realities and their occurance in a specific time and place occurs by God's will. In this way, they too are not evil as God is not malicious. What occurs in the heavens and earth, we believe, are signs and indications pointing back to Him - and they may also be warnings, punishments, or even opportunities. But we would never judge an act of nature as "evil".
I would go out on a pretty wide limb, but a limb none the less, and say that evil is not so much the actions themselves. To disobey God's guidance can be a wrong action, a major sin and even a crime. But what we term evil is generally the choice itself and the consequences of those actions. What i mean is that if someone murders, we see the fact that this person chose to take that life as evil. Under other circumstances we may not view the taking of a life as evil but good and so it is the intent and choice we are looking at. What is more, when someone chooses to use bullets laced with depleted uranium, the birth defects that span generations are viewed as an evil consequence of that evil act.
I believe that the topics of sin, evil, intellect and freewill must always be wrapped up together as it seems one can not exist without the entire package.
