LECTURE THREE

violation of what causes evolution

the violation of hardy weinberg assumptions

does evolution occur within or between generations

between generations

define random genetic drift

the random variation in allele frequencies frm one generation to the next

what are some causes of random genetic drift

mendelian segregation

finite population size

describe the relationship between impact of random genetic drift and population size

inversely proportional relationship

what does random genetic drift do long term

it reduce genetic variation within a population

what does random genetic drift cause divergence of

it causes different populations to diverge

describe the founder effect

reduced genetic diversity which results when a population is descended from a small number of colonising ancestors

describe the bottle neck effect

an event that drastically reduces population size

what is the effective population size

the number of individuals who contribute gametes to the next generation

what are the assumptions for effective population to equal actual population

fertile males = fertile females

all individuals likely to produce offspring

number of offspring made by each individual varies no more than expected by chance

random mating

number of breeding individuals constant from one generation to the next

define selection

operation of natural causes in which individuals of species best adapted to the environment tend to survive and transmit characteristics, whilst those less adapted die out. over time degree of adaptation to environment tends to progressively increase

what are the 2 types of fitness

absolute and relative

define absolute fitness

the average reproductive rate of a genotype

define relative fitness

the ability of a genotype to survive and reproduce compared with other genotypes in the population

what type of fitness does selection depend on

relative fitness only

what is overdominance

heterozygote advantage

stable polymorphism

what is underdominance

homozygous advantage

unstable polymorphism

what are the different effects of mutation

lethal

deleterious

neutral

advantageous

why are forward mutations more common than backward mutations

there are more ways to go forward than backward

when is mutation equilibirum attained

in the absence of other forces, after hundreds of generations