Biology 1001A Study Guide - Quiz Guide: Sickle-Cell Disease, Human Eye, Pleiotropy
Document Summary
Diseases of civilization: definition: disorders that arise due to a mismatch between our current environment and our ancestral environment, we are not currently living in the environment to which we are best suited (ancestral environment) Infectious diseases are no longer an issue we now deal with metabolic disorders and other conditions that never would have arisen in our ancestral environment: ex. In humans, exposure to various bacteria during development results in a reduced likelihood of allergies work for the immune system: ex. Trade-offs and competing demands: selection may maintain a harmful trait because it is beneficial in another aspect, ex. Allele that causes sickle cell anemia also provides malaria protection (in heterozygotes: antagonistic pleiotropy: if an allele is beneficial or neutral in early life, it will be maintained, regardless of the effects later in life, ex. High levels of sex hormones, storing fat quickly: occurs because everybody is born young, but not everybody lives to old age.
