Week 12 Post Quiz
How does a molecular clock measure time?
By counting the number of nucleotide substitution over a fixed period of time
How did Mendel's model of inheritance help explain Darwin's theory of natural selection?
By proposing a mechanism of how organisms could transmit discrete, heritable units to offspring
How can genetic variation at the whole gene level(gene variability) be quantified?
By the average percentage of loci that are heterozygous
Long necks make it easier for giraffes to reach leaves high on trees, while also making them better fighters in "neck wrestling"contests. In both cases, which kind of selection appears to have made giraffes the long-necked creatures they are today?
Directional selection
Black-bellied seedcrackers have either small beaks(better for eating soft seeds) or large beaks(better for hard seeds). There are no seeds of intermediate hardness; therefore, which kind of selection acts on beak size in seedcrackers?
Disruptive selection
Which type of selection tends to increase genetic variation?
Disruptive selection
Which statement about the beak size of finches on the island of Daphne Major during prolonged drought is true?
Each bird's survival was strongly influenced by the depth and strength of its beak as the drought persisted.
What is the frequency of the A1A2 genotype in a population composed of 20 A1A1 individuals, 80 A1A2 individuals, and 100 A2A2 individuals?
0.4
According to the principle of maximum parsimony,
the preferred tree is the one that minimizes the amount of evolutionary change.
Consider a population of wildflowers in which the frequency of the red allele CR is p=0.7 What is the frequency of the white allele(CW) in this population?
0.3
What is the correct order of steps for sorting phylogenetic trees
1. Identify the outgroup 2. Identify which character is common to all other individuals other than the outgroup 3. Identify which character is common to all but two of the individuals 4. Identify which character is shared by only two of the individuals 5. Identify which character is unique to only one individual 6. Place the individuals on the tree according to the characters.
If, on average, 46% of the loci in a species' gene pool are heterozygous, then the average homozygosity of the species should be
54%
Suppose that a population consist of 12 AA individuals, 36 Aa individuals, and 52 aa individuals. What are the expected genotype frequencies of this population, assuming that it is in Hardy-Weinberg equilibrium?
9% AA; 42% Aa; 49% aa
A shared ancestral character is
A character that originated in an ancestor of two taxa
Select the correct statement describing relative fitness in soapberry bugs
A soap berry bug with high relative fitness has a relatively high number of offspring that survive to reproductive age
In evolutionary terms, an organism's relative fitness is measured by its _.
Contribution to the gene pool of the next generation
True or false? Heterozygote advantage refers to the tendency for heterozygous individuals to have better fitness than homozygous individuals. This higher fitness results in less genetic variation in the population.
False
Which of the following are basic components of the Hardy-Weinberg model?
Frequencies of two alleles in a gene pool before and after many random matings
Allele frequencies in a gene pool may shift randomly and by chance. What its his random shift called?
Genetic drift
In the formula for determining a population's genotype frequencies, the 2 in the term 2pm is necessary because
Heterozygous can come about in two ways based upon parental gametes
Which process occurred frequently in the early history of the three domains on Earth and makes determining phylogenetic relationships of that time difficult?
Horizontal gene transfer
Natural selection changes allele frequencies because some _ survive and reproduce better than others
Individuals
Generation-to-generation change in the allele frequencies in a population is _.
Microevolution
Which kingdom has been replaced with two domains?
Monera(prokaryotes)
Which of the following evolutionary forces could created new genetic information in a population?
Mutation
Which of the following are causes of evolutionary change?
Mutation, genetic drift, natural selection, gene flow
Which of the following consistently improves the degree to which organisms are well suited for life in their environment?
Natural selection
Consider a wildflower population with the following allele and genotype frequencies. Frequency of the CR allele: p=0.6 Frequency of the CW allele: q=0.4 Frequency of CRCR: 50% Frequency of CRCW: 20% Frequency of CWCW: 30%
No, the frequency of genotype CRCW is too low
Small Aristelliger lizards have difficulty defending territories, but large lizards are more likely to be preyed upon by owls. Which kind of selection acts on the adult body size of these lizards?
Stabilizing selection
Women often have complications during labor while giving birth to very large babies, whereas very small babies tend to be underdeveloped. Which kind of selection is most likely at work regarding the birth weight of babies?
Stabilizing selection
Molecular clocks are based on the idea that _.
On average, neutral mutations arise at a constant rate
According to the Hardy-Weinberg theorem, the frequencies of alleles in a population will remain constant if _ is the only process acting on the gene pool.
Random mating
Which of the following evolutionary forces consistently results in adaptive changes in allele frequencies?
Selection
When using a cladistic approach to systematics, which of the following is considered most important for classification?
Shared derived characters
Heterozygote advantage should be most closely linked to which of the following?
Stabilizing selection
What genotype frequencies are expected under Hardy-Weinberg equilibrium for a population with allele frequencies of p=0.8 and q=0.2 for a particular gene?
The expected genotype frequencies are 0.64, 0.32, and 0.04 for A1A1, A1A2, and A2A2, respectively.
What is the frequency of the A1 allele in a population composed of 20 A1A1 individuals, 80 A1A2 individuals, and 100 A2A2 individual?
The frequency of the A1 allele is 0.3
Which of the following statements is not a part of the Hardy-Weinberg principle?
The genotype frequencies in the offspring generation must add put to two
Imagine you predict a particular frequency for a genotype, based upon detailed knowledge of that genotype frequency in population "X" of a species. Then, suing the Hardy-Weinberg model, you find that the observed genotype frequency in a different population, named "Y" of the same species, is not significantly different from what you predicted/expected based on population "X". Which of the following should you conclude?
The particular gene of interest is not undergoing any mechanism of evolution
The evolutionary effects of genetic drift are greatest when _
The population size is small
Phylogeny is the evolutionary history of related groups of organisms. Organisms are grouped into taxa based on homologous characteristics, shared traits that result rom common ancestry. Which statement is true?
The term "monophyletic" refers to a tax on that includes an ancestral species and all of its descendants.
In a bell-shaped curve, the X-axis(horizontal direction) of the graph represents which of the following?
The value of a particular characteristic; characteristics of an organism can include such traits as size and color
True or false? The Hardy-Weinberg model makes the following assumptions: no selection at the gene in question; no genetic drift; no gene flow; no mutation; random mating.
True
What is the founder effect?
When a few individuals become isolated from a larger population and their gene pool differs from that source population
What is a population in biology?
When a group of individuals of the same species live in the same area and interbreed
Which statement correctly describes the role of chance in evolution?
the ultimate source of new alleles is mutation, random changes in the nucleotide sequences of an organism's DNA
