BIOL 1510 Lecture Notes - Lecture 2: Heterozygote Advantage, Stabilizing Selection, Antimicrobial Resistance
Document Summary
For bacterial evolution in the videos above, here"s how darwin"s postulates apply: the population initially contains only antibiotic-sensitive alleles (meaning the antibiotic will kill the cells), but mutations generate antibiotic resistant alleles. The resistant bacteria are a better fit to the antibiotic-rich environment. Fitness: that the organisms that best match their environment will have relatively greater survival and reproduction than those that match less well. Adaptation: the resulting trait that is heritable and increases the survival and reproduction odds for those that carry that trait. Evolution by natural selection results in individuals that are a better fit to their environment. Evolution by natural selection occurs when the environment exerts a pressure on a population so that only some phenotypes survive and reproduce successfully. The stronger the selective pressure or the selection event the fewer individuals make it through the sieve of natural selection.
