BIO 148 Unit 6 Modes of Selection
Exam Questions and Answers||A+
Solution guide(Verified)
average fitness of the population _________ when selection occurs - Answer- increases
Gene pool - Answer- All of the alleles of all the genes in a certain population
Mutation - Answer- Any permanent change in the hereditary material of an organism
Deleterious - Answer- In genetics, referring to any mutation or allele that reduces an
individual's fitness
Beneficial - Answer- In genetics, referring to any mutation, allele, or trait that increases
an individuals fitness
Quantitative traits - Answer- A trait produced by the interaction and additive effects of
numerous genes (each of which contribute a small amount to phenotype)
Genetic variation - Answer- The number and relative frequency of alleles present in a
particular population
Directional selection - Answer- A pattern of natural selection that favors one extreme
phenotype with the result that the average phenotype of a population changes in One
Direction. Generally reduces overall genetic variation in a population
Stabilizing selection - Answer- A pattern of natural selection that favors phenotypes
near the middle of the range of phenotypic variation. Reduces overall genetic variation
in a population
Disruptive selection - Answer- A pattern of natural selection that favors extreme
phenotypes at both ends of the range of phenotypic variation. Generally increases
overall genetic variation in a population
Genetic drift - Answer- Any change in allele frequency's due to random events. Causes
allele frequency's to drift up and down randomly overtime, and eventually can lead to
the fixation or loss of alleles. Is more severe and smaller populations
Genetic bottleneck - Answer- A reduction in the size of a large population due to a
random event. Can lead to a change in allele frequency's and increases the effect of
genetic drift
, founder effect - Answer- A change in allele frequency's that often occurs when a new
population is established from a small group of individuals (founder event) due to a
sampling error (i.e., The small group is not a representative sample of the source
population)
Gene flow - Answer- The movement of alleles between populations; occurs when
individuals leave one population, join another, and breed
Sexual selection - Answer- A pattern of natural selection that favors individuals with
traits that increase their ability to obtain mates. Acts more strongly on males than
females
Sexual dimorphism - Answer- Any trait that differs between males and females
Biological species concept - Answer- The definition of a species as a population a group
of populations that are reproductively isolated from other groups. Members of a species
have the potential to interbreed in nature to produce viable, fertile offspring but cannot
produce viable, fertile hybrid offspring other species
Morphospecies conception - Answer- The definition of a species as a population or
group of populations that have measurably different anatomical features from other
groups
Phylogenetic species concept - Answer- The definition of a species of the smallest
monophyletic group in a phylogenetic tree
Monophyletic group - Answer- An evolutionary unit that includes an ancestral population
and all of its descendants but no others. Also called a clade
Paraphyletic group - Answer- An evolutionary unit that includes an ancestral population
and some but not all of its descendants
Allopatric speciation - Answer- The divergence of populations into different species by
physical isolation of populations in different geographic areas
Sympatric speciation - Answer- The divergence populations living with in the same
geographic area into different species as the result of their genetic not physical isolation
Phylogeny - Answer- The evolutionary history of a group of organisms
Outgroup - Answer- A taxon that is closely related to a particular monophyletic group
but is not part of it
Synapomorphy - Answer- A shared,, derived trait found in two or more taxa that is
present in their most recent common ancestor but is missing and more distant
ancestors
Exam Questions and Answers||A+
Solution guide(Verified)
average fitness of the population _________ when selection occurs - Answer- increases
Gene pool - Answer- All of the alleles of all the genes in a certain population
Mutation - Answer- Any permanent change in the hereditary material of an organism
Deleterious - Answer- In genetics, referring to any mutation or allele that reduces an
individual's fitness
Beneficial - Answer- In genetics, referring to any mutation, allele, or trait that increases
an individuals fitness
Quantitative traits - Answer- A trait produced by the interaction and additive effects of
numerous genes (each of which contribute a small amount to phenotype)
Genetic variation - Answer- The number and relative frequency of alleles present in a
particular population
Directional selection - Answer- A pattern of natural selection that favors one extreme
phenotype with the result that the average phenotype of a population changes in One
Direction. Generally reduces overall genetic variation in a population
Stabilizing selection - Answer- A pattern of natural selection that favors phenotypes
near the middle of the range of phenotypic variation. Reduces overall genetic variation
in a population
Disruptive selection - Answer- A pattern of natural selection that favors extreme
phenotypes at both ends of the range of phenotypic variation. Generally increases
overall genetic variation in a population
Genetic drift - Answer- Any change in allele frequency's due to random events. Causes
allele frequency's to drift up and down randomly overtime, and eventually can lead to
the fixation or loss of alleles. Is more severe and smaller populations
Genetic bottleneck - Answer- A reduction in the size of a large population due to a
random event. Can lead to a change in allele frequency's and increases the effect of
genetic drift
, founder effect - Answer- A change in allele frequency's that often occurs when a new
population is established from a small group of individuals (founder event) due to a
sampling error (i.e., The small group is not a representative sample of the source
population)
Gene flow - Answer- The movement of alleles between populations; occurs when
individuals leave one population, join another, and breed
Sexual selection - Answer- A pattern of natural selection that favors individuals with
traits that increase their ability to obtain mates. Acts more strongly on males than
females
Sexual dimorphism - Answer- Any trait that differs between males and females
Biological species concept - Answer- The definition of a species as a population a group
of populations that are reproductively isolated from other groups. Members of a species
have the potential to interbreed in nature to produce viable, fertile offspring but cannot
produce viable, fertile hybrid offspring other species
Morphospecies conception - Answer- The definition of a species as a population or
group of populations that have measurably different anatomical features from other
groups
Phylogenetic species concept - Answer- The definition of a species of the smallest
monophyletic group in a phylogenetic tree
Monophyletic group - Answer- An evolutionary unit that includes an ancestral population
and all of its descendants but no others. Also called a clade
Paraphyletic group - Answer- An evolutionary unit that includes an ancestral population
and some but not all of its descendants
Allopatric speciation - Answer- The divergence of populations into different species by
physical isolation of populations in different geographic areas
Sympatric speciation - Answer- The divergence populations living with in the same
geographic area into different species as the result of their genetic not physical isolation
Phylogeny - Answer- The evolutionary history of a group of organisms
Outgroup - Answer- A taxon that is closely related to a particular monophyletic group
but is not part of it
Synapomorphy - Answer- A shared,, derived trait found in two or more taxa that is
present in their most recent common ancestor but is missing and more distant
ancestors
