As far as evolution is concerned, we are kind of pausing it. Our advances in healthcare are keeping alive the genetically weak and allowing them to continue to pollute the gene pool. Obviously we shan't notice any immediate effects from this but it is nevertheless as legitimate a concern as others like to worry about. Worldwide, we cannot provide the whole world with food (a worsening situation given population growth); more vegetarians and environmentalists would signify the continuation of the journey to the end.
