Bio Ch 18

Front 1

population genetics

Back 1

study of genetic variablilty within a population & of the forces that act on it

Front 2

gene pool

Back 2

includes all the alleles for all the loci present in the population.

Front 3

genotype frequency

Back 3

proportion of a particular phenotype in the population. expressed as a decimal. (if 49% of a population has blue eyes, the genotype frequency is .49)

Front 4

phenotype frequency

Back 4

proportion of a phenotype

Front 5

allele frequency

Back 5

proportion of a specific allele.

Front 6

genetic equilibrium

Back 6

frequencies of alleles and genotypes don't change from generation to generation unless influenced by outside forces

Front 7

evolution

Back 7

allele frequencies change over succesive generations

Front 8

Hardy-weinberg equilibrium

Back 8

refers to an "ideal population" (perfect, where no evolution is occuring)

Front 9

p=
q=
p + q= ?

Back 9

frequency of a dominant allele
frequency of a recessiv allele
1.0

Front 10

p2
q2
2pq

Back 10

frquncy of AA
frquency of aa
frquency of Aa

Front 11

Genetic equilibrium

Back 11

if 5 conditions are met:
1- random mating
2- no net mutations
3- large population size
4- no migration
5- no natural selection

Front 12

random mating

Back 12

each individual has an equal chance of mating with any individual of the opposite sex

Front 13

no net mutations

Back 13

no mutations to convert alleles.

Front 14

large population size

Back 14

allele frequencies in a large population won't be changed by random fluctuations

Front 15

no migration

Back 15

no exchange with other populations that might have difrent allele frequencies. no individuals going in or out

Front 16

no natural selection

Back 16

if certain phenotypes are favored, the allele frequency will chage and evolution will occur

Front 17

microevolution

Back 17

evolution within a population

Front 18

2 examples of nonrandom mating

Back 18

inbreeding & assortative mating

Front 19

inbreeding

Back 19

mating of genetically similar individuals that are more related than if they were chosen at random from the entire population

Front 20

self-fertilization

Back 20

an example of inbreeding.

Front 21

inbreeding depression

Back 21

inbred individuals have lower fitness

Front 22

fitness

Back 22

relative ability of a given genotype to make a genetic contriution to subsequent generations

measured by the # of offspring who survive and pass on their genes to their offspring

Front 23

homozygosity

Back 23

mortality caused by expression of recessive alleles

Front 24

assortative mating

Back 24

individuals select their mates by attraction.(nonrandom mating)

Front 25

mutation

Back 25

unpredictable, spontaneous. mutations in somatic cells don't get passed down.

Front 26

genetic variability

Back 26

increases by mutations.

Front 27

genetic drift

Back 27

production of random evolutionary changes in small breeding populations. alleles may be eliminated by chance

Front 28

genetic bottleneck effect

Back 28

fluctuations in the environment-depletion of food, disease, hurricanes- population may rapidly decrease from time to time

Front 29

founder effect

Back 29

when one or a few individuals from a large population find a new colony

Front 30

gene flow

Back 30

migration of indivuals causes a movement of alleles

Front 31

sufficient gene flow

Back 31

populations become more similar genetically

Front 32

natural selection

Back 32

differential reproducitve success. weeds out those individuals whose phenotypes are less adapted

Front 33

stabilizing selection

Back 33

phenotypic extremes are selected against.
ex: human birth weight-7 lbs

Front 34

directional selection

Back 34

if environment changes...directional selection may favor phenotypes at one of the extremes

Front 35

disruptive selection

Back 35

evironment favors 2 or more diffrent phenotypes.

Front 36

what makes genetic variation?

Back 36

-crossing over
-independent assortment of chromosomes
-union of gametes

Front 37

genetic polymorphism

Back 37

presence in a population of 2 or more genes for a given locus

Front 38

balanced polymorphism

Back 38

2 or more alleles persist in a population over many generations b/c of natural selection

Front 39

heterozygote advantage

Back 39

heterozygote has a higher degree of fitness.

Front 40

sickle-cell anemia and heterozygote

Back 40

Aa-normal
AA- die of malaria
aa- die of sickle cell

Front 41

neutral variation

Back 41

variation that does not alter the ability of an individual to survive and reproduce and not adaptive