Evilution Flashcards
Several closely related frog species of the genus Rana are found in the forests of the southeastern United States. One species lives only in tree holes; another species lives only in streams. This is an example of which
reproductive barrier?
Habitat
Some scientist claim that amphibians are currently experiencing a period of mass extinction. Which of the following should be included in an alternative hypothesis that would best support this claim?
The current extinction rate of amphibians compared with the background rate of extinction as determined by the fossil record
If the frequency of a particular allele that is present in a small, isolated population of alpine plants decreases due to a landslide that leaves an even smaller remnant of surviving plants bearing this allele, then what has
occurred?
A bottleneck
Which of the following is NOT a requirement for maintenance of Hardy-Weinberg equilibrium?
an increasing mutation rate
Based on morphological
Characteristics, the phylogenetic tree above has been developed for species I, Il, Ill, and IV. DNA sequencing has recently been completed for a particular gene found in all four species. The sequencing will provide additional information for answering which of the following questions?
Are species Ill and IV the most closely related?
A defining characteristic of allopatric speciation is
geographic isolation
A biologist spent many years researching the rate of evolutionary change in the finch populations of a group of islands. It was determined that the average beak size (both length and mass) of finches in a certain population increased dramatically during an intense drought between 1981 and 1987. During the drought, there was a reduction in the number of plants producing thin-walled seeds.
Which of the following statements might best explain the increase in average beak size in the finch population during the drought?
Finches with bigger beaks are better able to crack thick-walled seeds and produce more surviving offspring
According to the concept of
punctuated equilibrium, the “sudden” appearance of a new species in the fossil record means that
speciation occurred rapidly in geologic time
Sexual dimorphism is most often a
result of
intersexual selection
Which of the following statements best expresses the concept of punctuated equilibrium?
Evolutionary changes consist of rapid bursts of speciation alternating with long periods in which species remain essentially unmodified
Two species of frogs belonging to the same genus occasionally mate, but the offspring fail to develop and hatch. What is the mechanism for keeping the two frog species separate?
the postzygotic barrier called hybrid inviability
Neuromodulin is an essential protein that is highly conserved among vertebrates. Researchers compared the first 60 amino acids of the neuromodulin protein from each of five different species. The results are shown in the table below.
Top to bottom: Zebra fish, frog, finch, turtle, gecko
The frequency of the recessive allele is
0.4. What is the percentage of a population that is homozygous for that allele?
0.4^2=0.16
The validity of the cladogram is best supported by molecular evidence for which of the following changes in the amino acid composition of the beta-hemoglobin protein during the evolution of these species?
Arginine to leucine at position X on the cladogram
Five new species of bacteria were discovered in Antarctic ice core samples. The nucleotide (base) sequences of RNA subunits were determined for the new species.
The table below shows the number of nucleotide differences between the species.
Top to bottom: 3,4,2,1,5
Several closely related frog species of the genus Rana are found in the forests of the southeastern
United States. Females of one species choose mates based on song quality; females of another species choose mates on the basis of size. This is an example of which reproductive barrier?
Behavioral
Several closely related frog species of the genus Rana are found in the forests of the southeastern United States. One species lives only in tree holes; another species lives only in streams. This is an example of which
reproductive barrier?
Habitat
