Biology 1001A Lecture 23:
29 Jan 2019
School
Department
Course
Document Summary
Evolutionary (ultimate) explanations for why we get sick. Infectious diseases- we evolve in response to them and vice versa simultaneo. Some symptoms may have enhanced our fitness throughout much of our evo history. Depression- adaptation to prepare for a lack of food in the winter- decreased. Smoke alarm principle- defenses are often overly sensitive. Not true of all symptoms- some are adaptations of parasites themselves. Environment is changing so fast that we are not yet adapted to current condi. Current environment is very different from evolutionary environment. Access to birth control- lifetime number of menstrual cycle. Changing risk of infectious disease (decrease) vs autoimmune diseases (rapid. "harmful" alleles may be maintained by heterozygote advantage. Antagonistic pleiotropy- a trait of allele increases the fitness of an organism i while decreasing the organisms fitness in another. Traits that increase survival or attractiveness in early life tend to be favored, reduce longevity.
