Gene pool
Collection of alleles found in all of the individuals of a population
Allele frequency
Proportion one allele, compared with all the alleles for that trait, in the gene pool
Normal distribution
Distribution in a population in which allele frequency is highest near the mean range value and decreases progressively toward each extreme end
Microevolution
Observable change in the allele frequencies of a population over a few generations
Directional selection
Pathway of natural selection in which one uncommon phenotype is selected over a more common phenotype
Stabilizing selection
Pathway of natural selection in which intermediate phenotypes are selected over phenotypes at both extremes
Disruptive selection
Pathway of natural selection in which two opposite, but equally uncommon, phenotypes are selected over the most common phenotype
Gene flow
Physical movement of alleles from one population to another
Genetic drift
Change in allele frequencies due to change alone, occuring most commonly in small populations
Bottleneck effect
Genetic drift that results from an event that drastically reduces the size of a population
Founder effect
Genetic drift that occurs after a small number of individuals colonize a new area
Sexual selection
Selection in which certain traits enhance mating success; traits are, therefore, passed on to offspring
Different Phenotypes
What differences found in species' population does natural selction act on?
Genetic variation
What makes these different phenotypes possible within a species population?
Survive in a changing environment
Genetic variation in species' populations results in more members of the species being able to do what?
gene pool
How is genetic variation stored in a species' population?
Combined alleles
The gene pool for all the individuals within a population includes what from all the individuals of that population?
Mutations
Recombination
Hybridization
What are the three main sources of genetic variation?
DNA of the gene; new allele
What do mutations result in a random change in? What can these mutations form?
Recombination
During what process do new allele combinations form in offspring through parental alleles changing places?
Meiosis
In what process of genetic replication does recombination occur most often?
Hybridization
What term is given to the crossing of two different species that share common genes?
Mean
When the value of the distribution of traits is shown on a graph, what term describes the most common traits?
Extreme phenotypes
Which type of phenotypes are less common in a species' phenotype distribution?
A drop on each end of the bell-curve
How are extreme phenotypes represented on a graph showing trait distribution?
Environmental conditions changing suddenly
What would result in less common phenotypes being more advantageous to a population?
Directional selection
Stabilizing selection
Disruptive selection
What are three different paths through which natural selection can change the distribution of a trait?
Extreme phenotypes
What becomes more common in directional selection?
Intermediate phenotypes
Which kind of phenotype becomes more common in the species' population during stabalizing selection?
Dramatically decline over time
What happens to the most common traits in a species' population during disruptive selection?
Move between populations
Gene flow occurs when individuals of the same species do what?
Genetic variation
What increases as a result of gene flow?
Loss of genetic diversity
What effect does genetic drift have on the genotypes of a species' population?
Bottleneck effect
Founder effect
What are the two main processes of genetic drift?
survive
Both sexes of a species benefit from their offspring being able to do what?
Offspring have the best genetics possible
What does a female ensure for her offspring by choosing the best mate possible?
Intrasexual selection
Intersexual selection
What are the two types of sexual selection?
Healthy and good genetic quality
Males of a species convince females that they posses what two qualities during intersexual sleection?
Gene pool
Collection of alleles found in all of the individuals of a population
Allele frequency
Proportion one allele, compared with all the alleles for that trait, in the gene pool
Normal distribution
Distribution in a population in which allele frequency is highest near the mean range value and decreases progressively toward each extreme end
Microevolution
Observable change in the allele frequencies of a population over a few generations
Directional selection
Pathway of natural selection in which one uncommon phenotype is selected over a more common phenotype
Stabilizing selection
Pathway of natural selection in which intermediate phenotypes are selected over phenotypes at both extremes
Disruptive selection
Pathway of natural selection in which two opposite, but equally uncommon, phenotypes are selected over the most common phenotype
Gene flow
Physical movement of alleles from one population to another
Genetic drift
Change in allele frequencies due to change alone, occuring most commonly in small populations
Bottleneck effect
Genetic drift that results from an event that drastically reduces the size of a population
Founder effect
Genetic drift that occurs after a small number of individuals colonize a new area
Sexual selection
Selection in which certain traits enhance mating success; traits are, therefore, passed on to offspring
Different Phenotypes
What differences found in species' population does natural selction act on?
Genetic variation
What makes these different phenotypes possible within a species population?
Survive in a changing environment
Genetic variation in species' populations results in more members of the species being able to do what?
gene pool
How is genetic variation stored in a species' population?
Combined alleles
The gene pool for all the individuals within a population includes what from all the individuals of that population?
Mutations
Recombination
Hybridization
What are the three main sources of genetic variation?
DNA of the gene; new allele
What do mutations result in a random change in? What can these mutations form?
Recombination
During what process do new allele combinations form in offspring through parental alleles changing places?
Meiosis
In what process of genetic replication does recombination occur most often?
Hybridization
What term is given to the crossing of two different species that share common genes?
Mean
When the value of the distribution of traits is shown on a graph, what term describes the most common traits?
Extreme phenotypes
Which type of phenotypes are less common in a species' phenotype distribution?
A drop on each end of the bell-curve
How are extreme phenotypes represented on a graph showing trait distribution?
Environmental conditions changing suddenly
What would result in less common phenotypes being more advantageous to a population?
Directional selection
Stabilizing selection
Disruptive selection
What are three different paths through which natural selection can change the distribution of a trait?
Extreme phenotypes
What becomes more common in directional selection?
Intermediate phenotypes
Which kind of phenotype becomes more common in the species' population during stabalizing selection?
Dramatically decline over time
What happens to the most common traits in a species' population during disruptive selection?
Move between populations
Gene flow occurs when individuals of the same species do what?
Genetic variation
What increases as a result of gene flow?
Loss of genetic diversity
What effect does genetic drift have on the genotypes of a species' population?
Bottleneck effect
Founder effect
What are the two main processes of genetic drift?
survive
Both sexes of a species benefit from their offspring being able to do what?
Offspring have the best genetics possible
What does a female ensure for her offspring by choosing the best mate possible?
Intrasexual selection
Intersexual selection
What are the two types of sexual selection?
Healthy and good genetic quality
Males of a species convince females that they posses what two qualities during intersexual sleection?