evolutionary medicine exam 2

evolutionary medicine

intergration of medicine and evolutionary biology, the change in focus from disease to the aspects of the body that make it vulnerable to disease

evolutionary explanation of disease

- defenses

- a trait being beneficial in one enviornment but not another

- the enviornment has changed faster then the body can keep up and diseases result from this mismatch

- evolutionary legacies

- tradeoffs between traits

- genetic quirks

- conflict between organisms

example of evolutionary explanation of disease : defense

Fevers

example of evolutionary explanation of disease :a trait being beneficial in one enviornment but not another

sickle cell cell fighting malaria

example of evolutionary explanation of disease :the enviornment has changed faster then the body can keep up and diseases result from this mismatch

rise in obesity, and type 2 diabetes in modern populations

example of evolutionary explanation of disease: evolutionary legacies

the link between human immune system evolution and the modern prevalence of autoimmune disorders

example of evolutionary explanation of disease: trade offs between traits

light skin is benefical in northern climates but harmful in southern climates

example of evolutionary explanation of disease: Genetic quirks

Cystic fibrosis resistance to cholera which is why it is still around

example of evolutionary explanation of disease: conflict between organisms

blood types may have evolved due to pathogen pressures—for example, certain microbes preferentially infect one blood type over another

latency

period of inactivation of pathogen inside the host

incubation period

the time between infection and symptom onset

R0

the number of secondary infections that result from a single infected individual entering a population of entirely susceptible individuals

herd immunity

the resistance to the spread of a contagious disease within a population that results if a sufficiently high proportion of individuals are immune to the disease, especially through vaccination.

co-evolution

Process by which two species evolve in response to changes in each other

example of coevolution

bees are able to see blue and yellow and bilateral symmetry so plants that are polinated by bees favor those things while the plant exerts pressure on the bee favoring hairness and body shape which benefits pollen transfer.

fishchers fundamental therom

rate of evolution is proportinal to the amount of genetic variance in the population.

epidemic disease

outbreak of the disease in a particular area

endemic disease

disease constantly present in a population

pandemic disease

an epidemic disease that occurs worldwide

requirements for a pandemic

1. emergance of new or siginfigantly changed pathogen

2. the pathogen causes illness in humans

3. efficient sustained person to person spread

Virulence

morbidity and mortality caused by pathogen

the harm done to hosts following infection

"harm"=decreased fitness

virulence theory 1

parasites should evolve to be mutualists/symbionts (peaceful coexstence)

why is theory 1 wrong

kin selection only works in certain scenarios

increased host explotation can benefit parasites through greater conversion of host resources in paristite reproduction

host and parastie dont evolve into the same end goals

virulence theory 2

virulence is coincidental

what is wrong with theory 2

new pathogens arent always harmful

assumes avirulence in true host

virulence theory 3

virulence is a parastie adaptation

- direct benefit to the parasite

host evolution too slow to prevent virulence

virulence theory 4

within host competition among parasites

arms race within host

virulence decreases when within host genetic relatedness of parasites increases

virulence theory 5

virulence depends on mode of transmission