Some questions for you

[Angrboda]

Hi guys, I am a Christian and I like to compare worldviews with atheists/other religions etc. If you're up for it I have some questions for you, I promise these are not so I can preach or assert irrational beliefs, I've read the forum rules for theists 
Also I am not trying to catch anyone out, I am a thinker and I just genuinely want to know what you think about these things too.

1. What is morality? Do good and evil exist?

I think you probably mean to ask what is the basis of morality. That's a question to which there are many answers, none of them definitive or conclusive. Typically, Christians assert that the mandates of what is and is not moral come from God, or are simply a part of His nature. Similarly, many atheists believe that morals and morality reflect our nature as evolved social beings. They believe that morals are a response to pressures to survive, that they represent an instinctual response to certain kinds of questions which are not answered by rational responses nor surface drives toward survival. The moral is "the group response" to these questions.

2. Presuming that we are highly evolved biological machines whose main motivation is to survive and adapt, why, in societies in general, is there such a collective fixation with love? By this I mean the romantic love expressed in movies, pop music etc. In many movies there seems to be one story, that is, there is a hero, things go bad, the hero finds love, the hero fights for love, the bad is defeated, the hero wins the love. Why is this story so deeply ingrained in our collective subconsciousness? 

Romantic love is a relatively recent arrival in terms of human history. Before that was pair bonding and marriage. Regardless of the form it takes, the drive to pair up and mate serves several purposes. First, it provides a context for sexual activity. Second, it provides males with an ability to ensure that their resources go only to offspring of their mating. And finally, because the child is dependent upon the parents for a significant period after birth, it provides a mechanism for ensuring that both parents contribute to the upbringing of offspring.

3. Why does justice matter to each of us? If someone harms us or someone we love, we want them to pay the consequences. But why should there be consequences for our actions? That would imply judgement and an judge. What if the person that harmed us was merely executing their right to survival of the fittest?

Justice is a part of our moral response, addressed above. The usual judgement and judge considered is society. Societies reserve the right to punish its members who violate the rules. If you were to find yourself in a remote island with no legal authority in place, then actions might very well go by without consequence. (The anthropological data on this is not clear cut. Even groups with no law may find themselves banding together to oppose someone regularly taking advantage of others. Where does our concept of a champion come from?) And there is no such thing as a right to survival of the fittest.