ANT203H5 Chapter Notes - Chapter 15: Zygosity, Lactose Intolerance, Ultraviolet
Document Summary
Natural selection has been operating throughout hominin evolution, resulting in a number of major anatomical changes, such as the origin of bipedalism. Sickle cell anemia: a genetic disease that occurs in a person homozygous for the sickle cell allele, which alters the structure of red blood cells - oxygen transport is severely impaired. Infection disease: a disease caused by the introduction of an organic foreign substance into the body non-infectious disease: a disease caused by factors other than the introduction of an organic foreign substance in the body. Malaria causes by a parasite that enters body through bite of mosquito. *sickle cell anemia and malaria both related to high frequencies of the s allele. Presence of 1 s allele does not give the person sickle cell anemia, but it does change the blood cells sufficiently so that the malaria parasite does not have as serious an effect. ->shows the importance of the specific environment on the process of natural selection.
