Bio 2
What conclusion can be drawn from the observation that a population is not in Hardy-Weinberg equilibrium?
Evolutionary forces are affecting the population
In a population of seahorses, red seahorses on average produce 125 offspring and brown seahorses produce 75 offspring. What is the fitness of the brown phenotype?
0.6
Consider a population with 100 cats. If 72 cats are black and 28 are white, what is the phenotypic frequency of black cats?
0.72
The most fit phenotype is assigned a fitness value of ______.
1
Consider a gene that has 4 alleles in a particular population: F, M, S, and VS. What is the sum of all of the frequencies of all the alleles for this gene in that population?
1, 1.0, or 100%
Select all of the following that could cause evolutionary change by natural selection.
A plant with an enzyme that makes it disease-resistant A moth that has a gene for cryptic coloration
Which evolutionary mechanism changes genotype frequencies but does not change allele frequencies?
Assortative mating
Which type of selection favors individuals at one extreme of a phenotypic range who have greater reproductive success in a particular environment?
Directional selection
Selection against intermediate-sized beaks in African black-bellied seedcracker finches is an example of which of the following
Disruptive selection
Select the conditions that must be met for a population to be in Hardy-Weinberg equilibrium.
Mating is random. The population is very large. No new mutations occur.
What is the ultimate source of all new alleles?
Mutation
Select all of the following processes that can cause changes in allele or genotype frequencies in populations.
Natural selection Nonrandom Mating Mutations Genetic drift Gene flow
What is fitness?
The relative likelihood that a genotype will contribute to the gene pool of the next generation
The phenotype frequency is calculated by dividing the total number of individuals with a particular phenotype by which of the following?
The total number of individuals in that population
Select all of the following criteria that must be present for natural selection to occur and cause evolutionary change in a population.
Variation must result in differences in the number of offspring surviving in the next generation. Variation must exist among individuals. Variation must have a genetic basis.
Consider a gene with two alleles, A1 and A2. If the fitness of A1A2 individuals is higher than the fitness of both A1A1 and A2A2, we are observing
heterozygote advantage.
Fitness is a measure of (choose all that apply)
mating success. survival. number of offspring produced per mating.
Why does selection occur?
Because some individuals in a population possess more favorable phenotypes than others.
selection is a process that can lead to change, and evolutionary changeBlank 2Blank 2 evolutionary change , Incorrect Unavailable is the outcome or record of change over time.
Blank 1: Natural Blank 2: Evolution
Which of the following agents of evolutionary change occurs when alleles move from one population to another?
Gene flow
Evolutionary change is not caused by phenotypic variation if the phenotypic variation lacks which of the following?
Genetic basis
Many 19th century scientists believed that natural selection always favored an optimal form, and therefore would tend to reduce or eliminate which of the following?
Genetic variation
By favoring different phenotypes at different times, oscillating selection acts in which way?
It maintains genetic variation in a population.
Which evolutionary mechanism causes beneficial traits that are heritable to become more common in a population?
Natural selection
If we find evidence that a population is experiencing changes in allele frequencies from one generation to the next, we say that this population is which of the following?
Not in Hardy-Not in Hardy-Weinberg equilibrium
Choose all the components of fitness from the list below:
Production of viable, numerous offspring Individual survival Mating success
How can the founder effect cause a previously rare genetic disorder to become common in the new population?
The allele frequencies in the founding members of the population differ from the allele frequencies in the original large population.
The most fit phenotype produces, on average, which of the following?
The greatest number of surviving offspring
Natural selection results in ______ in a population.
adaptations
The term heterozygote (blank) refers to situations in which heterozygotes are more fit then either homozygotes.
advantage
Natural selection can lead to if variation is genetically based
evolution or evolutionary change
In - selection, the fitness of a phenotype depends on the proportion of individuals in the population that have that phenotype.
frequency dependecy
Evolution can result from any process that changes the ______ composition of a population.
genetic
Changes in allele frequencies within a population may result from , which are changes in the nucleotide sequences of an organism's DNA.
mutations
Natural selection results in a population better adapted to its environment because
only individuals who are well adapted to the environment contribute their alleles to the next generation.
Ground finches with large bills are favored during times of drought, while ground finches with small bills are favored during times when water is abundant. This is an example of
oscillating selection
For a gene with two alleles, what equation represents the sum of all gene frequencies?
p + q = 1
directional selction
shift of a population toward an extreme version of a beneficial trait
The amount of genetic variation present in naturally occurring populations is
significant
(Blank) selection favors individuals with intermediate phenotypes and selects against individuals with extreme phenotypes.
stabilizzing selection favors individuals with intermediate phenotypes and selects against individuals with extreme phenotypes.
In frequency-dependent selection
the fitness of a phenotype depends on its frequency in the population.
