ADAPTABILITY (SPECIES) AND EVOLUTION
Ince some gene changes (mutations) can happen in sex cells(sexual reproduction) these mutations are heritable and pass on the next generation. The carpenter's son will not be born with larger hand and arm muscles (and the calluses and tanned skin). If, However, there is mutatin in one of the carpenter's sperm cells to gene that controls hemoglobin formation in red blood cells, and that sperm cell fertilizes an egg cell, the embryo may develop red blood cells with a slightly different hemoglobin. If the changed hemoglobin doesn't workas well as normall hemoglobin, the child will be at a disadvantage and may not reproduce, or may produce fewer offspring than people with "normal"hemoglobin. Then population is becoming resistant to the disease- in time it is adapting as a group-it is evolving. Populations evolve, not individuals.