Within six months of effectively using methicillin to treat S. aureus infections in a community, all new infections were caused by MRSA. How can this result best be explained?
Some drug-resistant bacteria were present at the start of treatment, and natural selection increased their frequency.
Which of the following is an example of the process of evolution?
herbivory
After invoking selective breeding of domesticated species as evidence that groups of organisms are capable of change, he then proposed that natural populations can change as well. On which two lines of evidence did he base this proposal
Organisms within a population vary, and all populations produce more offspring than can be supported by the environment, resulting in competition for survival within the population.
According to the theory of evolution, anatomical and molecular homologies should
produce similar patterns of evolutionary relatedness
If the nucleotide variability of a locus equals 0%, what is the gene variability and number of alleles at that locus?
gene variability = 0%; number of alleles = 1
average heterozygosity
average percentage of loci that are heterozygous in a population NOT # of individuals
cline
a graded change in a character along a geographic axis
Rabbits that live in colder regions tend to have smaller ears than rabbits of the same species that live in warmer regions
p^2
EXPECTED frequency
Antibiotic resistance in bacteria is an example of which of the following?
directional selection
Antibiotic resistance acts opposite to disruptive selection in that it promotes the growth of only those bacteria with the resistant gene.
Which of the following evolutionary mechanisms does NOT contribute to the process of allopatric speciation
gene flow