Chapter 20 Flashcards
(22 cards)
Describe how fever is a defense mechanism
Evolved mechanism to fight infection; regulate temperatures; iguana in hot and cold shows it is used to fight infection because it gave itself a fever
Proximate cause of disease
What is causing the disease now
Example of proximate causes
Fever; if you know how it came about, you know how to treat it
Describe coevolution of pathogens
Bacteria/pathogens evolve faster than our immune systems
Describe the mismatch between evolution and changing environment
Evolve one way and things have changed; example of human heads vs monkey heads and birth canal
Evolutionary Relic
Species representing a formerly diverse group
Hygiene Hypothesis
Increased allergies and autoimmune disease from being too clean, evolving pathogens
What does natural selection and disease do together?
Selected for things with higher reproduction, may make you more susceptible later
Why do pathogens adapt so quickly?
Short generation times and large population sizes
How do we overcome the quickly evolving pathogens?
Antibodies help to recognize 10 million antigens, use adaptive immunology to react differently to antigens
B cells use of somatic recombination
Recombination to generate diverse immune response, cells that react with self proteins are deleted, immune cell binds an antigen from pathogen and proliferates rapidly, high mutation rate generates variation in the receptors of proliferating cells. After pathogen is cleared; some of responding cells are retained to provide memory immunity
Escape Variance
Influenza evolves by developing a pathogen not detected by antigen
Examples of trade offs
Choking; designed to talk but need less overlap
How do diseases come from mismatches?
We evolve in certain environments, creating increased allele frequency; now in a changed environment these are detrimental
Examples of disease from mismatch
Obesity, hypertension, need for glasses, sickle cell
Senescence
General decline in physical function as we age
Rate of living hypothesis
Says aging is a consequence of the physical ware and tare; implies selection has done its work; says inverse relationship between metabolic rates and life span
Why is Haldane and Huntingtin’s Disease not eliminated from the population?
Symptoms come late in life; natural selection cannot delete certain mutations after reproduction
Mutation Accumulation hypothesis
Accumulation of deleterious mutations that occur later in life because natural selection cannot see them because of lots of extrinsic mortality
Antagonistic pleiotropic hypothesis
Trade offs, mutation that is really good early in life is really bad later in life
Support for antagonistic and mutation hypothesis
Groups of organisms with protections against mortality have longer life spans
Why are we the species with the most cancer?
Tradeoffs; big testes for better reproduction, antagonistic pleiotropy; positive first, but not later, mismatch; high altitude and lighter skin
