parsimony principle Answer - 1.) simplest explanation
2.) tree with the fewest character transition
3.) fewest homoplasies
artificial selection Answer - 1.) breeding for desirable traits
2.) humans determine an organisms fitness through selective breeding
natural selection Answer - 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 Answer - can be passed from parent to offspring
differential reproductive success (DRS) Answer - individuals with more
desirable traits will be more likely to pass those traits to future generations
evolution Answer - changes in biological populations (NOT individuals) over
time
3 things necessary for natural selection to occur Answer - 1.) Variation in the
trait
,2.) Heritability
3.) Impact on reproductive success
gene pool Answer - sum of all of the alleles for a particular locus in a
population
adaptation Answer - 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 Answer - change in the nucleotide sequence (random)
2 sources of phenotypic variation Answer - V(g) - genetic variation
V(e) = environmental variation
V(p) = V(g) + V(e)
heritability Answer - 1.) (h^2) = V(g)/V(p)
2.) Fraction of variability NOT fraction of trait that is genetic
parent-offspring regression line Answer - 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 Answer - 1.) quantify response to natural selection in terms
of heritability and selection differential (S)
2.) R = (h^2)(S)
, selection differential (S) Answer - measure of the intensity of selection on a
particular trait
fitness Answer - genotype and phenotype's contribution to the genetic
composition of future generations; which organisms are more likely to survive
AND reproduce
Directional selection Answer - one extreme phenotype is the fittest
mean changes, variance does not
ex: TX longhorns
Stabilizing selection Answer - 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 Answer - 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) Answer - occurs when a phenotype's
fitness depends on how common it is in the population
positive FDS Answer - most common phenotype is favored