CH 20&21 Bio 122

A fruit fly population has a gene with two alleles, A1 and A2. Tests show that 70% of the gametes produced in the population contain the A1 allele. If the population is in Hardy-Weinberg equilibrium, what proportion of the flies carry both A1 and A2?

0.42

Arrange the following from most general (most inclusive) to most specific (least inclusive): 1.)Natural Selection 2.) Microevolution 3.) Intrasexual selection 4.) Evolution 5.) Sexual selection

4,2,1,3,5 (Evolution, microevolution, natural selection, intrasexual selection, and sexual selection)

Which statement about variation is true?

All new alleles are the result of nucleotide variability.

In the figure shown below, which similarly inclusive taxon dscended from the same common ancestor as Canidae?

Mustelidae

What is true of natural selection? A) Natural selection is a random process. B) Natural selection creates beneficial mutations. C) The only way to eliminate harmful mutations is through natural selection. D) Mutations occur at random; natural selection can preserve and distribute beneficial mutations. E) Mutations occur when directed by the good of the species; natural selection edits out harmful mutations and causes populations to adapt to the beneficial mutations.

Natural selection creates beneficial mutations

Which statement about the beak size of finches on the island of Daphne Major prolonged drought is true?

The frequency of the strong-beak alleles increased in each bird as the drought persisted

Three living species X, Y, and Z share a common ancestor T, as do extinct species U and V. A grouping that consists of species T, X, Y, and Z (but not U or V) makes up

a paraphyletic group

In a comparison of birds and mammals, the condition of having four limbs is

a shared ancestral character

There are those who claim that the theory of evolution cannot be true because the apes, which are supposed to be closely related to humans, do not likewise share the same large brains, capacity for complicated speech, and tool-making capability. They reason that if these features are generally beneficial, then the apes should have evolved them as well. Which of these provides the best argument against this misconception? A) Advantageous alleles do not arise on demand. B) A populationʹs evolution is limited by historical constraints. C) Adaptations are often compromises. D) Evolution can be influenced by environmental change.

advantageous alleles do not arise on demand

If the original finches that had been blown over to the Galapagos from South America had already been genetically different from the parental population of South American finches, even before adapting to the Galapagos, this would have been an example of A) genetic drift. B) bottleneck effect. C) founderʹs effect. D) all three of these E) both A and C

all three of these

Which variable is likely to undergo the largest change in value resulting from a mutation that introduces a new allele into a population at a locus for which all individuals formerly had been fully homozygous?

average number of loci

To apply parsimony to constructing a phylogenetic tree,

choose the tree that represents the fewest evolutionary changes, in either DNA sequences or morphology

The best classification system is that which most closely

conforms to traditional, Linnaean taxonomic practices

Which of the following is most likely to produce an African butterfly species in the wild whose members have one of two strikingly different color patterns?

disruptive selection

In seedcracker finches from Cameroon, small- and large-billed birds specialize in cracking soft and hard seeds, respectively. If long-term climatic change resulted in all seeds becoming hard, what type of selection would then operate on the finch population?

directional selection

When imbalances occur in the sex ratio of sexual species that have two sexes (i.e., other than a 50:50 ratio), the members of the minority sex often receive a greater proportion of care and resources from parents than do the offspring of the majority sex. This is most clearly an example of A) sexual selection. B) disruptive selection. C) balancing selection. D) stabilizing selection. E) frequency-dependent selection.

frequency-dependent selection

Which kingdom has been replaced with two domains?

fungi

If the nucleotide variability of a locus equals 0%, what is the gene variability and number of alleles at that locus?

gene variability= 0%; number of alleles= 1

There are 25 individuals in population 1, all with genotype AA, and there are 40 individuals in population 2, all with genotype aa. Assume that these populations are located far from each other and that their environmental conditions are very similar. Based on the information given here, the observed genetic variation most likely resulted from

genetic drift

Over time, the movement of people on Earth has steadily increased. This has altered the course of human evolution by increasing

geographic isolation

The recessive allele that causes phenylkentonuria (PKU) is harmful, except when an infant's diet has appropriate levels of the animo acid phenylalanine. What maintains the prescence of this harmful allele in a population's gene pool?

heterozygotes advantage

In the formula for determining a population's genotype frequencies, the 2 in the term 2pq is necessary because

heterozygotes have two alleles

If, someday, an archaean cell is discovered whose rRNA sequence is more similar to that of humans than the sequence of mouse rRNA is to that of humans, the best explanation for this apparent discrepancy would be

homoplasy

Natural selection changes allele frequencies because some....... survive and reproduce more successfully than others.

individuals

Some molecular data place the giant panda in the bear family (Ursidae) but place the lesser panda in the raccoon family (Procyonidae). Consequently, the morphological similarities of these two species are probably due to

inheritance of shared derived characters

Adult male humans generally have deeper voices than do adult female humans, which is the direct result of higher levels of testosterone causing growth of the larynx. If the fossil records of apes and humans alike show a trend toward decreasing larynx size in adult females and increasing larynx size in adult males, then

intrasexual selection seems to have occurred

The most important feature that permits a gene to act as a molecular clock is

its recent origin by a gene-duplication event.

Based on the tree below, which statement is not correct?

lizards are more closely related to salamanders than to humans

A phylogenetic tree constructed using sequence differences in mitochondrial DNA would be most valid for discerning the evolutionary relatedness of

mosses and ferns

Which of these would, if it had acted upon a gene, prevent this gene from acting as a reliable molecular clock?

most substitution mutations involving an exonic codon's third position

Although each of the following has a better chance of influencing gene frequencies in small populations than in large populations, which one most consistently requires a small population as a precondition for its occurrence?

mutation

A proficient engineer can easily design skeletal structures that are more functional than those currently found in the forelimbs of such diverse mammals as horses, whales, and bats. The actual forelimbs of these mammals do not seem to be optimally arranged because

natural selection is generally limited to modifying structures that were present in previous generations and in previous species.

The same gene that causes various coat patterns in wild and domesticated cats also causes the cross -eyed condition in these cats, the cross-eyed condition being slightly maladaptive. In a hypothetical environment, the coat pattern that is associated with crossed eyes is highly adaptive, with the result that both the coat pattern and the cross-eyed condition increase in a feline population over time. Which statement is supported by these observations? A) Evolution is progressive and tends toward a more perfect population. B) Phenotype is often the result of compromise. C) Natural selection reduces the frequency of maladaptive genes in populations over the course of time. D) Polygenic inheritance is generally maladaptive, and should become less common in future generations. E) In all environments, coat pattern is a more important survival factor than is eye-muscle tone.

phenotype is often the result of compromise

Which eukaryotic kingdom is polyphyletic, and therefore unacceptable, based on cladistics?

protista

Evolution

requires that populations become better suited to their environments

Heterozygote advantage should be most closely linked to which of the following?

sexual selection

When using a cladistic approach to systematics, which of the following is considered most important for classification?

shared derived characters

Sparrows with average-sized wings survive severe storms better than those with longer or shorter wings, illustrating

stabilizing selection

The term homoplasy is most applicable to which of the following features?

the B hemaglobin genes of mice and of humans

Whenever diploid populations are in Hardy-Weinberg equilibrium at a particular locus

the allele's frequency should not change from one generation to the next, but its representation in homozygous and heterozygous genotypes may change.

The relative lengths of the frog and mouse branches in phylogenetic tree in the figure given below indicate that

the homolog has evolved more slowly in mice

No two people are genetically identical, except for identical twins. The main source of genetic variation among human individuals is

the reshuffling of alleles in sexual reproduction

The various taxonomic levels (namely, genera, classes, etc.) of the hierarchial classification system differ from each other on the basis of

their inclusiveness

When it acts upon a gene, which of the following processes consequently makes that gene an accurate molecular clock?

transcription

If you were using cladistics to build a phylogenetic tree of cats, which of the following would be the best outgroup?

wolf