Ethics is a systematic approach to questions of right and wrong. Ultimately our ethical concerns have to do with our wellbeing as individuals and as small communities within the greater community of humankind.
Throughout human history, people have wrestled with how best to approach ethical questions--how to balance the happiness of an individual against the wellbeing of other individuals or the collective. Each ethical philosophy or religion expresses some attempt to find this balance.
Although ethics is a field of rational, scholarly discourse, the beginnings of ethics are built into our very bodies. They are rooted in moral emotions such as empathy, shame, and guilt. Moral intuition and reasoning emerge similarly in children across cultures, and they are nurtured by adults. We build on these moral emotions and instincts by making agreements with each other, weigh costs and benefits of different courses of action, looking to ethical scholars, and drawing on the wisdom of our ancestors.