In a 1000 word essay, explain how both sickle cell anemia and human skin pigmentation are examples of human evolution. For both examples, describe which of the four forces of evolution are at work, and how they have influenced, and may be still influencing these traits. Finally, explain what data and evidence has been used by scientists to demonstrate the validity of these claims. Resources: Jablonski- Human Skin Pigmentation as an Example of Adaptive Evolution Livingstone- Implications of Sickle Cell Gene Distribution in West Africa Textbook: Chapters 1-5 Skin Pigmentation – Ch. 5 pg.147-150 Sickle Cell Anemia – Ch. 4 pg.107 – 111 REMEMBER: Natural Selection is dependent upon an individual being able to reach reproductive age. If the individual does not reach reproductive age, their genes will not be passed on to the next generations. Further, even if a trait has negative effects, if it does not prevent the individual from reaching reproductive age it will be passed on to the next generation (keep this in mind when thinking about skin cancer).