What is the meaning of life without God?

I don't understand the idea that something is meaningful only if it is significant to a supreme ruler of the universe or that 'meaning' can only be provided by something larger than humanity. To transcend our humanity, we'd have to forego such human concepts as love, friendship, compassion, ethics, dignity. science, philosophy and art - everything that comes from human brains and is meaningful to the great ape we call homo sapiens. In reality, everything we do is related to our humanity, including the worship of gods we have endowed with human emotions, values and concepts. To ascribe meaning to a god is simply to take it from an earlier humanity without the benefit of everything we have discovered and thought in the hundreds of years since.