Walmart assistant managers average $45,000 a year, which is right on target for the national average salary, according to Glassdoor salary data. If you factor in bonuses and additional compensation, the average pay increases to $48, 311 a year.
Natural selection can only work on existing variation within a population. Such variations arise by mutation, a change in some part of the genetic code for a trait. Mutations arise by chance and without foresight for the potential advantage or disadvantage of the mutation.
However, by far the most important agent of evolution is (5) natural selection, which operates by differential reproductive success of individuals. Natural selection is the only directed evolutionary mechanism resulting in conformity between an organism and its environment. This is how adaptations arise and are maintained.