BIO 320 ECOLOGY EXAM 2 CURRENTLY TESTING QUESTIONS WITH COMPLETE
SOLUTIONS
What is the mode of selection if a phenotype has intermediate values that are favored over
extreme values?
Stabilizing selection
What is the mode of selection if extreme values of a phenotype are favored over
intermediate values?
Disruptive selection
What is stabilizing selection?
When individuals with intermediate phenotypes have higher survival and reproductive
success than those with extreme phenotypes.
When does stabilizing selection dominate?
When the environment of a population is relatively unchanging.
What happens to the average phenotype in stabilizing selection?
It does not change significantly.
What is directional selection?
,When an extreme phenotype experiences higher fitness than the average phenotype.
What is the optimal phenotype in directional selection?
The value that confers the greatest fitness.
What is disruptive selection?
When individuals with extreme phenotypes at either end of the distribution have higher
fitness than individuals with intermediate phenotypes.
What is the consequence of migration?
Homogenizing populations and reducing genetic differences between them.
What is selection?
The process by which certain phenotypes are favored to survive and reproduce over other
phenotypes.
What is migration?
The movement of individuals from one population to another, resulting in gene flow.
What is gene flow?
The movement of alleles from one population to another.
, What is mutation?
A change in the DNA sequence of a gene.
What increases the probability of mutation?
Having more genes in a species and a larger population size.
How does genetic drift contribute to evolution?
It can lead to random changes in allele frequencies in a population.
How does natural selection contribute to evolution?
It favors certain phenotypes, leading to changes in allele frequencies.
How does migration contribute to evolution?
It introduces new alleles into a population, changing allele frequencies.
How does mutation contribute to evolution?
It introduces new genetic variation into a population.
SOLUTIONS
What is the mode of selection if a phenotype has intermediate values that are favored over
extreme values?
Stabilizing selection
What is the mode of selection if extreme values of a phenotype are favored over
intermediate values?
Disruptive selection
What is stabilizing selection?
When individuals with intermediate phenotypes have higher survival and reproductive
success than those with extreme phenotypes.
When does stabilizing selection dominate?
When the environment of a population is relatively unchanging.
What happens to the average phenotype in stabilizing selection?
It does not change significantly.
What is directional selection?
,When an extreme phenotype experiences higher fitness than the average phenotype.
What is the optimal phenotype in directional selection?
The value that confers the greatest fitness.
What is disruptive selection?
When individuals with extreme phenotypes at either end of the distribution have higher
fitness than individuals with intermediate phenotypes.
What is the consequence of migration?
Homogenizing populations and reducing genetic differences between them.
What is selection?
The process by which certain phenotypes are favored to survive and reproduce over other
phenotypes.
What is migration?
The movement of individuals from one population to another, resulting in gene flow.
What is gene flow?
The movement of alleles from one population to another.
, What is mutation?
A change in the DNA sequence of a gene.
What increases the probability of mutation?
Having more genes in a species and a larger population size.
How does genetic drift contribute to evolution?
It can lead to random changes in allele frequencies in a population.
How does natural selection contribute to evolution?
It favors certain phenotypes, leading to changes in allele frequencies.
How does migration contribute to evolution?
It introduces new alleles into a population, changing allele frequencies.
How does mutation contribute to evolution?
It introduces new genetic variation into a population.
