LS7B Final Exam Best Answers 2024-2025
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Allele frequencies
rates of occurrence of alleles in populations
Fixed
when a population exhibits only one allele at a particular gene
Fitness
a measure of the extent to which the individual's genotype is represented in the next
generation
Heritability
in the population, the proportion of the total variation in a trait that is due to genetic
differences among individuals
Stabilizing selection
maintains the status quo and acts against extremes
Directional selection
leads to a change in a trait over time
Disruptive selection
operates in favor of extremes and against intermediate forms, selecting against the mean
Gene pool
all the alleles present in all individuals in a population or species
Gene flow
homogenized allele frequencies between two populations
Assumptions of HW
1: No differences in the survival and reproductive success of individuals
2: No migration
,3: No mutations
4: Must be sufficiently large population size
5: Must be random mating
Variation
Mutation generates new variation; Recombination followed by segregation of homologous
chromosomes during meiotic cell division shuffles mutations to create new combinations
Random mating
mate choice must be made without regard to genotype
Inbreeding
mating occurs between close relatives; Increases frequency of homozygote and decreases the #
of heterozygotes without affecting allele frequencies
Inbreeding depression
a reduction in the child's fitness caused by homozygosity of deleterious recessive mutations
Genetic drift
a change in the frequency of an allele due to the random effects of limited population size
Migration
reduces genetic variation between populations;
Results in gene flow: the movement of alleles from one population to another
Mutation
increases genetic variation
Founder effect
a type of bottleneck that occurs when only a few individuals establish a new population
Non-random mating
individuals mate based on genotype; alters genotype frequencies without affecting allele
frequencies
Kin selection
a form of natural selection that favors the spread of alleles that promote behaviors that help
close relatives, or kin
, Altruism
behavior that benefits another individual at a cost to the altruist's personal fitness (ability to
produce offspring)
Reciprocal altruism
individuals exchange favors; Individuals must be able to recognize one another and remember
previous interactions
Direct fitness
the number of offspring an individual produces
Indirect fitness
the number of relatives produced multiplied by the degree of relatedness to those individuals
Sexual selection
promotes traits that increase an individual's access to reproductive opportunities
Natural selection
a process in which individuals that have certain inherited traits tend to survive and reproduce at
higher rates than other individuals because of those traits
Sexual selection
A form of selection in which individuals with certain inherited characteristics are more likely
than other individuals to obtain mates; often powerful enough to produce features that are
harmful to the individual's survival
Hamilton's Rule
Being related to individuals and how this impacts your fitness;
rB > C; As long as rB exceeds C, altruism can evolve
Adaptive traits
a genetic trait that helps an organism to maximize its reproductive success; enhance individual
survival and reproduction of individuals in a population
Non-adaptive trait
not affected by fitness
Biological species concept
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Allele frequencies
rates of occurrence of alleles in populations
Fixed
when a population exhibits only one allele at a particular gene
Fitness
a measure of the extent to which the individual's genotype is represented in the next
generation
Heritability
in the population, the proportion of the total variation in a trait that is due to genetic
differences among individuals
Stabilizing selection
maintains the status quo and acts against extremes
Directional selection
leads to a change in a trait over time
Disruptive selection
operates in favor of extremes and against intermediate forms, selecting against the mean
Gene pool
all the alleles present in all individuals in a population or species
Gene flow
homogenized allele frequencies between two populations
Assumptions of HW
1: No differences in the survival and reproductive success of individuals
2: No migration
,3: No mutations
4: Must be sufficiently large population size
5: Must be random mating
Variation
Mutation generates new variation; Recombination followed by segregation of homologous
chromosomes during meiotic cell division shuffles mutations to create new combinations
Random mating
mate choice must be made without regard to genotype
Inbreeding
mating occurs between close relatives; Increases frequency of homozygote and decreases the #
of heterozygotes without affecting allele frequencies
Inbreeding depression
a reduction in the child's fitness caused by homozygosity of deleterious recessive mutations
Genetic drift
a change in the frequency of an allele due to the random effects of limited population size
Migration
reduces genetic variation between populations;
Results in gene flow: the movement of alleles from one population to another
Mutation
increases genetic variation
Founder effect
a type of bottleneck that occurs when only a few individuals establish a new population
Non-random mating
individuals mate based on genotype; alters genotype frequencies without affecting allele
frequencies
Kin selection
a form of natural selection that favors the spread of alleles that promote behaviors that help
close relatives, or kin
, Altruism
behavior that benefits another individual at a cost to the altruist's personal fitness (ability to
produce offspring)
Reciprocal altruism
individuals exchange favors; Individuals must be able to recognize one another and remember
previous interactions
Direct fitness
the number of offspring an individual produces
Indirect fitness
the number of relatives produced multiplied by the degree of relatedness to those individuals
Sexual selection
promotes traits that increase an individual's access to reproductive opportunities
Natural selection
a process in which individuals that have certain inherited traits tend to survive and reproduce at
higher rates than other individuals because of those traits
Sexual selection
A form of selection in which individuals with certain inherited characteristics are more likely
than other individuals to obtain mates; often powerful enough to produce features that are
harmful to the individual's survival
Hamilton's Rule
Being related to individuals and how this impacts your fitness;
rB > C; As long as rB exceeds C, altruism can evolve
Adaptive traits
a genetic trait that helps an organism to maximize its reproductive success; enhance individual
survival and reproduction of individuals in a population
Non-adaptive trait
not affected by fitness
Biological species concept
