Question

How can a change in allele frequency for a single gene trait affect an orgnisms life spam?

Answer 1

Hm. This is an odd question because "allele frequency" is typically a term that refers to the allele distribution at the ~population~ level not the individual level, but I suppose if the allele frequency for a single-gene trait changes, it might change the phenotype distribution for that species, either decreasing or increasing an individual's relative likelihood of survival