PCB 4674: Exam 2
______________ reduces differentiation among populations - [ANSWER] Migration (gene
flow)
Movement of alleles into or out of a population due to the migration of individuals to or
from the population - [ANSWER] Gene flow
One individual migrating into a population per generation is enough to prevent
______________ __________ between two populations despite population size - [ANSWER]
genetic drift
A trend toward uniformity, a consequence of gene flow - [ANSWER] Homogenization
Gradual shift in gene frequencies between neighboring populations; natural selection
steepens and migration smooths out; consequence of gene flow - [ANSWER] Clines
Disruption of gene flow is usually a requirement for ______________________ -
[ANSWER] speciation
When migration counteracts natural selection, a(n) __________________
_________________ is reached between the two processes - [ANSWER] intermediate
equilibrium
__________________ _________________ and population structure can reduce effective
population size - [ANSWER] Breeding behavior
__________________ ____________ distorts Hardy-Weinburg equilibrium but does not
itself change allele frequencies - [ANSWER] Nonrandom mating
______________________ usually reduces the fitness of offspring and numerous
mechanisms have evolved to prevent it - [ANSWER] Inbreeding
Population structure with one female and several males - [ANSWER] Polyandry
Population structure with one male and several females - [ANSWER] Polygyny
Population structure where there is a difference between individuals ability to produce an
abundance of offspring or new growth - [ANSWER] Unequal fecundity
Population structure where there is a difference between the ability of individuals to
successfully mate - [ANSWER] Unequal mating success
, Ne = (4NmNf)/(Nm + Nf) - [ANSWER] Effective population size
Occurs when organisms are more or less likely to mate with others of their genotypes than
by chance... - [ANSWER] Nonrandom mating
The inbreeding coefficient; a measure of population subdivision and the propensity to
genetic drift - [ANSWER] F
Refers to the probability that the two alleles at any locus in an individual will be identical
because of common descent - [ANSWER] Inbreeding coefficient (F)
HF = H0(1-F)
Relates inbreeding to the number of heterozygotes - [ANSWER] Heterozygosity (as it
relates to F)
Inbreeding reduces the number of ___________________ in a population - [ANSWER]
heterozygotes
_____________________ ______________ mimics the effects of long-term inbreeding
because it increases the probability of identity by descent - [ANSWER] Genetic drift
A ____________ ______________ can mimic the effects of inbreeding since alleles can be
identical by descent even if there is random mating in small populations - [ANSWER] large
population
Mating system, population subdivision, and interbreeding - [ANSWER] 3 ways to reduce
effective population size
Inbreeding temporarily increases _________________ __________________. But over the
long term decreases the _________________ ________________ by reducing population
size - [ANSWER] phenotypic variation; genetic variation
Alleles that cause a decrease in fitness and are exposed more frequently in homozygotes -
[ANSWER] Deleterious recessives
... produce offspring that have an impaired ability to survive and reproduce - [ANSWER]
Inbreeding depression
... choose not to breed with them - [ANSWER] Mate choice
... move gametes away from parent organism - [ANSWER] Dispersal
... to prevent selfing - [ANSWER] Self-incompatibility
... to avoid selfing - [ANSWER] Dioecy
______________ reduces differentiation among populations - [ANSWER] Migration (gene
flow)
Movement of alleles into or out of a population due to the migration of individuals to or
from the population - [ANSWER] Gene flow
One individual migrating into a population per generation is enough to prevent
______________ __________ between two populations despite population size - [ANSWER]
genetic drift
A trend toward uniformity, a consequence of gene flow - [ANSWER] Homogenization
Gradual shift in gene frequencies between neighboring populations; natural selection
steepens and migration smooths out; consequence of gene flow - [ANSWER] Clines
Disruption of gene flow is usually a requirement for ______________________ -
[ANSWER] speciation
When migration counteracts natural selection, a(n) __________________
_________________ is reached between the two processes - [ANSWER] intermediate
equilibrium
__________________ _________________ and population structure can reduce effective
population size - [ANSWER] Breeding behavior
__________________ ____________ distorts Hardy-Weinburg equilibrium but does not
itself change allele frequencies - [ANSWER] Nonrandom mating
______________________ usually reduces the fitness of offspring and numerous
mechanisms have evolved to prevent it - [ANSWER] Inbreeding
Population structure with one female and several males - [ANSWER] Polyandry
Population structure with one male and several females - [ANSWER] Polygyny
Population structure where there is a difference between individuals ability to produce an
abundance of offspring or new growth - [ANSWER] Unequal fecundity
Population structure where there is a difference between the ability of individuals to
successfully mate - [ANSWER] Unequal mating success
, Ne = (4NmNf)/(Nm + Nf) - [ANSWER] Effective population size
Occurs when organisms are more or less likely to mate with others of their genotypes than
by chance... - [ANSWER] Nonrandom mating
The inbreeding coefficient; a measure of population subdivision and the propensity to
genetic drift - [ANSWER] F
Refers to the probability that the two alleles at any locus in an individual will be identical
because of common descent - [ANSWER] Inbreeding coefficient (F)
HF = H0(1-F)
Relates inbreeding to the number of heterozygotes - [ANSWER] Heterozygosity (as it
relates to F)
Inbreeding reduces the number of ___________________ in a population - [ANSWER]
heterozygotes
_____________________ ______________ mimics the effects of long-term inbreeding
because it increases the probability of identity by descent - [ANSWER] Genetic drift
A ____________ ______________ can mimic the effects of inbreeding since alleles can be
identical by descent even if there is random mating in small populations - [ANSWER] large
population
Mating system, population subdivision, and interbreeding - [ANSWER] 3 ways to reduce
effective population size
Inbreeding temporarily increases _________________ __________________. But over the
long term decreases the _________________ ________________ by reducing population
size - [ANSWER] phenotypic variation; genetic variation
Alleles that cause a decrease in fitness and are exposed more frequently in homozygotes -
[ANSWER] Deleterious recessives
... produce offspring that have an impaired ability to survive and reproduce - [ANSWER]
Inbreeding depression
... choose not to breed with them - [ANSWER] Mate choice
... move gametes away from parent organism - [ANSWER] Dispersal
... to prevent selfing - [ANSWER] Self-incompatibility
... to avoid selfing - [ANSWER] Dioecy
