How does antibiotic resistance evolve in populations? What is the agent of selection? Natural selection to a new environment. Antibiotics. Ex. If a bacterium is resistant to antibiotics, it will be favored to reproduce. How does Darwins concept of descent with modification explain both the unity and diversity of life? Favorable traits are passed down, which is descent with modification, which causes new species but at the same time, all species are linked through common ancestors. Genetic terminology review Know the following terms: allele, gene, locus, homozygous, heterozygous, codominance, replication, transcription, translation, proofreading, point mutation, silent, missense, and nonsense mutations Allele: Variant form of a given gene. (Produces distinguishable phenotypes). Gene: Segment of DNA codes for a protein. Locus: Location of a gene on the length of a chromosome. Homozygous: Having two identical alleles for a given gene. Heterozygous: Having two different alleles for a given gene. Codominance: Phenotypes of both alleles are exhibited in the heterozygote because both alleles affect the phenotype in separate, distinguishable ways . Replication: When new DNA is recreated from old DNA. Transcription: Where DNA is copied onto mRNA. Translation: Where the code carried by mRNA is coded into amino acids. Proofreading: DNA polymerases ability to check over DNA to look for mistakes. Point Mutation: Mutation where only one nucleotide is affected. Silent Mutation: Point mutation where the same amino acid is coded for. Missense Mutation: Point mutation that codes for a different amino acid and affects phenotype. Nonsense Mutation: Causes reading of the stop codon too early. Evolution of populations (Chap 21) Define microevolution. Microevolution: Change in allele frequencies over a short time within a population. Review the medium ground finch study discussed in lecture (and text). What are the sources of genetic variation? Mutation, gene flow, sex. What is a gene pool? The stock of different genes in an interbreeding population. What is the HardyWeinberg (HW) principle? Did Hardy and Weinberg work as a team? Genotypic and allele frequencies dont change from generation as long other evolutionary factors are not present. Yes.