How would helping "the species as a whole" increase the frequency of that person's genetic traits in the population? It sounds very pretty and virtuous -- get ahead by helping others, hooray -- but the math just doesn't work.
This could work through group selection - on average, groups containing more intelligent individuals would outcompete groups not containing them. However, this requires a scenario with group competition, and probably also requires substantially more time than individual selection for the dynamic to play out.
How so? Having the sickle cell trait (i.e. being heterozygous for the gene which, in homozygous individuals, causes sickle cell anemia) gives an advantage to individual evolutionary fitness in areas where malaria is a big problem. There's no need for group selection arguments to explain the prevalence of that trait.
