Biology 1M03 - Midterm Exam Questions With Correct Answers

convergent evolution - Answer the process by which organisms are not closely related, but independently evolve similar traits that help them adapt to similar environments evolution - Answer the process by which living organisms have developed and diversified from earlier forms during the history of the earth natural selection - Answer a process by which individuals with certain alleles produce the most surviving offspring in a population fitness - Answer the ability for an individual to produce offspring (highest fitness = more offspring) adaptation - Answer a characteristic that increases fitness of an individual in a specific environment cell theory - Answer proposes that all organisms are composed of cells, and all cells come from preexisting cells what are 3 factors that need to be present in order for natural selection to occur - Answer 1) variation in species 2) heritable traits 3) influenced fitness artificial selection - Answer the breeding of plants/animals to produce desirable traits (eg. designer babies) *note - artificial selection is dependent on genetic variation speciation - Answer formation of a new & distinct species in the course of evolution the tree of life - Answer diagram that depicts relationships among species *note - tree of life cannot be observed, it can only be inferred from data L.U.C.A - Answer last - universal - common - ancestor developmental homology - Answer a similarity among species in embryonic traits that is due to shared ancestry homology - Answer a similarity that exists in species that was inherited from an ancestor ` homoplasy - Answer a character shared by species but not present in their common ancestor the Hardy-Weinberg principle - Answer a null hypothesis that predicts what genotype frequencies should be given known allele frequencies *note - sum of all gene phenotypes should = 1 allele - Answer a variant of a gene allele frequency - Answer the frequency of each allele genotype frequency - Answer the frequency of each genotype phenotype frequency - Answer the frequency of each phenotype 4 factors that change allele frequecies - Answer 1) natural selection 2) genetic drift 3) gene flow (migration) 4) mutation fitness trade-off - Answer a compromise between traits, in terms of how those traits are adapted for the environment genetic drift - Answer any change in allele frequencies in a population that is due to chance (allele frequencies drift up and down randomly over time) *note - genetic drift in small populations = reduced variation genetic correlation - Answer occurs when selection favouring alleles for one trait causes a correlation, but suboptimal change in an allele for another trait historical constraints - Answer present variation biases future possibles (species evolve from ancestors) formal constraints - Answer evolution needs to work within the laws of physics temporal constraints - Answer evolution occurs by mutation and and it takes time for a series of useful mutation *note - mutation is slow what are two ways to tell if a population is not in HWE - Answer 1) excess homozygous homotypes 2) excess heterozygous homotypes disruptive selection - Answer maintains or increases the amount of variation in a trait directional selection - Answer changes in the average value of a trait stabilizing selection - Answer reduces the amount of variation in a trait founder effect - Answer a change in allele frequencies that occurs when a new population is established (when a new group of individuals immigrates to a new geographic area and establishes a new population) genetic bottleneck - Answer a sudden reduction in the number of alleles in a population gene flow (migration) - Answer the movement of alleles from one population to another, occurs whenever individuals leave a population and join another and breed