Genes don't reproduce, individuals do. But they do so preferentially, depending upon the genes they have. Nevertheless if one allele confers a reproductive advantage to its possessor, that gene should increase over time. Dawkins selfish gene concept. Darwin envisioned selection acting upon individuals and so do I for the most part.
Selection can then favor the expansion, contraction or even extinction of competing populations.
Group selection which favors evolution of traits good for the population, but bad for the individual. Hard to imagine how this works. If an altruist dies protecting others, his genes go with him. Cheaters at advantage. If altruist dies, but close relatives survive the altruist is still putting his or her genes in the next generation.