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.
Natural selection results in organisms with different characteristics (caused by mutations and crossovers) thriving in different environments. Beside the Green and Gray Treefrog (our example above, showing adaptation through camouflage), there are many ways natural selection shapes organisms: