"Evolution by means of natural selection."
Evolution
- change in the form of organisms (new forms of organisms)
- change in frequency of alleles
Natural selection = mechanism of evolution (Charles Darwin)
Example:
Stapholococcus aureus = infection of skin, lungs (due to wounds e.g. operations)
-> Susceptible to being killed by Methecillin (Antibiotic)
S.A. which can be killed are known as the susceptible forms of the population
-> SUSCEPTIBLE: MSSA (methecillin susceptible s.a)
-> RESISTANT: Random Mutation to S.A. allows it to break down methecillin = no longer susceptible
When both forms are treated by methecillin (MSSA, MRSA)
-> SUSCEPTIBLE: less common, decrease in population
-> RESISTANT: more common, increase in population = increase in FREQUENCY of allele for resistance
*different forms = definition of evolution -> MRSA = evolved form of MSSA due to alterations in genome
PROCESS of NATURAL SELECTION
-> Random mutation = produces MRSA form
-> Non-random selection = applying antibiotics, MRSA selected for survival/MSSA
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