Class Notes (806,814)
Canada (492,451)
Biology (6,676)
Biology 1001A (1,723)
Tom Haffie (1,166)

L23 - Evolutionary Medicine

4 Pages
Unlock Document

Western University
Biology 1001A
Tom Haffie

How does evolution affect human health? - pathogens evolve (resistance to vaccines, medicines) - we can attempt to shape their evolution - traces of evolutionary history affect our health - trade-offs between competing demands - symptoms may be defenses not defects Evolution of Pathogens - New diseases are emerging all the time - Evolution of pathogens pose risks to human health Diseases of Civilization (1) Metabolic Syndrome - high calorie foods were a limited resource - evolutionary ancestors were not adapted to such rich foods - “metabolic syndrome” (obesity, diabetes, insulin resistance) was not prevalent in ancestors - thrifty genotypes more favoured - reflects a disease of civilization – reflects currently occupied environment is different than environment to which we are evolutionarily adapted - (2) Myopia - partly heritable ( if one twin has it the other likely will as well) - in evolutionary history myopia poses threat to fitness  why would selection favour evolution of this trait? - Barrow Inuit study (1970)  42% of 6-35 yrs myopic  5% of 36-88 yr olds myopic  Why? - not a difference in allele frequencies; exposed to different visual environment in early development  alleles pre-disposing people to myopia did not cause myopia in ancestral visual environment (3) Autoimmune Disorders - on the rise as infections diseases decline - reflects combat introduced by medicine - infectious diseases on decline as our ability to combat them becomes more refined  driven by medical advancements - autoimmune disorder – body’s immune system reacts to ‘mild’ toxins and attacks its own immune system - underdeveloped countries exhibit lower risk for autoimmune disorders and higher infectious disease (4) Hygiene Hypothesis: - we are adapted to “dirtier” environments - we were not previously exposed to the pathogens we are today - lower rates of infectious disease - acquiring pathogens in early life is important in regulating immune system in present environment - hyperactivity of immune system Risk of Having Allergies - decreased if you have: * older siblings * a dog * grew up on a farm * rarely washed hands as a child * grew up in a dusty home * fecal-oral ^^ based on mismatch between environment where we spent most of our evolutionary history and the environment we are presented with today Major Threats to Health - starvation (then) - infectious disease (then AND now, different diseases) - predators (then) - accidents - heart attack/stroke (now) - cancer (now) - metabolic syndrome (now) - autoimmune disorders (now) Historical Constraints - optic nerve in humans creates a blind spot that is non existent in squid eyes - appendix – vestigial trait, serves no purpose at present * risk of appendicitis results in maintenance of appendix – has been shrunk to minimal size. “evolutionarily stuck” Tradeoffs and Competing Demands - selection may maintai
More Less

Related notes for Biology 1001A

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.