UF BSC 2010 Exam 3 Questions with Correct Answers Latest Update

UF BSC 2010 Exam 3 Questions with Correct Answers Latest Update parsimony principle - Answers 1.) simplest explanation 2.) tree with the fewest character transition 3.) fewest homoplasies artificial selection - Answers 1.) breeding for desirable traits 2.) humans determine an organisms fitness through selective breeding natural selection - Answers 1.) differential reproductive success of certain individuals with more or less desirable traits 2.) acts on heritable variation in a way that favors the traits that lead to reproductive fitness and promotes adaptive evolution 3.) only acts on existing variation 4.) DOES NOT act on genotypes, favor the perfect phenotype, or create genetic variation heritable - Answers can be passed from parent to offspring differential reproductive success (DRS) - Answers individuals with more desirable traits will be more likely to pass those traits to future generations evolution - Answers changes in biological populations (NOT individuals) over time 3 things necessary for natural selection to occur - Answers 1.) Variation in the trait 2.) Heritability 3.) Impact on reproductive success gene pool - Answers sum of all of the alleles for a particular locus in a population adaptation - Answers 1.) beneficial mutation favored by natural selection 2.) refers to both the favored trait and the process by which the trait emerges in the population mutation - Answers change in the nucleotide sequence (random) 2 sources of phenotypic variation - Answers V(g) - genetic variation V(e) = environmental variation V(p) = V(g) + V(e) heritability - Answers 1.) (h^2) = V(g)/V(p) 2.) Fraction of variability NOT fraction of trait that is genetic parent-offspring regression line - Answers relates traits of offspring to biological parents ex: slope 0f 0.5 - 1/2 of the variability is due to the parents Breeder's equation - Answers 1.) quantify response to natural selection in terms of heritability and selection differential (S) 2.) R = (h^2)(S) selection differential (S) - Answers measure of the intensity of selection on a particular trait fitness - Answers genotype and phenotype's contribution to the genetic composition of future generations; which organisms are more likely to survive AND reproduce Directional selection - Answers one extreme phenotype is the fittest mean changes, variance does not ex: TX longhorns Stabilizing selection - Answers 1.) aka purifying selection 2.) stabilize around intermediate trait as genetic variation decreases 3.) Fitness is highest at average phenotype 4) mean doesnt change, variance changes ex: human birth weight Disruptive selection - Answers 1.) trait tends toward BOTH extremes 2.) Causes the emergence of two species 3.) bimodal distribution leads to eventual sympatric speciation 4.) rarest of all the selections ex: bird beaks frequency-dependent selection (FDS) - Answers occurs when a phenotype's fitness depends on how common it is in the population positive FDS - Answers most common phenotype is favored negative FDS - Answers rare phenotype is favored in the poulation fixation - Answers a given allele is the only allele in the population and all other variations have been lost sexual selection - Answers 1.) non-random mating in which an organism's phenotype impacts its choice of mating 2.) traits favored are often costly to males population genetics - Answers study of how evolutionary forces cause allele frequencies to change over time