BIO 114 CH 19-24 Final Exam
Which of these evolutionary agents is most consistent at causing populations to become better suited to their environments over the course of generations?
Natural selection
Which statement best describes the evolution of pesticide resistance in a population of insects?
Offspring of insects that are genetically resistant to the pesticide become more abundant as the susceptible insects die off.
Postzygotic Barriers- Reduced Hybrid Fertility
Offspring of two newts are sterile.
In a hypothetical environment, fishes called pike-cichlids are visual predators of algae-eating fish (i.e., they locate their prey by sight). -If a population of algae-eaters experiences predation pressure from pike-cichlids, which of the following should least likely be observed in the algae-eater population over the course of many generations?
Selection for larger female algae-eaters, bearing broods composed of more, and larger, young
One of the characteristics of retrotransposons is that
they code for an enzyme that synthesizes DNA using an RNA template.
Double-stranded viral DNA is incorporated into a host cell as a _____.
provirus -"Provirus" is the name given to double-stranded viral DNA that has been incorporated into a host cell's genome.
Direct observation of evolutionary change.
development of drug resistance in bacteria
Multigene families include two or more nearly identical genes or genes sharing nearly identical sequences. A classical example is the set of genes for globin molecules, including genes on human chromosomes 11 and 16. Several of the different globin genes are expressed in humans, but at different times in development. -What mechanism could allow for this?
differential gene regulation over time
Bacteria containing recombinant plasmids are often identified by which process?
exposing the bacteria to an antibiotic that kills cells lacking the resistant plasmid
Homology.
-similarities in mammalian forelimbs -vestigial pelvis in right whales -same genetic code in fireflies and tobacco plants
Why are the large finches now living on the Galápagos Islands different from the original source population from a nearby island?
-Genetic drift occurred in the two populations. -The separation of habitats reduced gene flow between the populations. -Natural selection favored individuals that were more fit in the new environment.
True or false? The last ice age produced many different species mainly because populations dispersed and colonized new habitats.
False -The last ice age produced many different species mainly because of vicariance events; the glaciers physically separated populations from each other.
The sticky end of the DNA restriction fragment shown here will pair with a DNA restriction fragment with the sticky end _____.
-ACGT --The matching of sticky ends follows the rules of specific base pairing.
Fossil record.
-discovery of shells of extinct species -discovery of transitional forms of horses
Biogeography.
-marsupial mammals in Australia -similarity of endemic island species to nearby mainland species
Prezygotic Behaviors-Gametic Isolation
A corals sperm can't fertilize another's egg.
What is genetic drift?
A change in allele frequencies caused by random events
Within a few weeks of treatment with the drug 3TC, a patient's HIV population consists entirely of 3TC-resistant viruses. -How can this result best be explained?
A few drug-resistant viruses were present at the start of treatment, and natural selection increased their frequency.
Which of the following is characteristic of the lytic cycle?
A large number of phages is released at a time.
Which of the following is a major distinction between a transposon and a retrotransposon?
A transposon moves via a DNA intermediate and a retrotransposon via an RNA intermediate.
Which of these binds to receptor molecules on the host cell membrane?
A. Glycoproteins on the viral envelope recognize and bind to receptors on the host cell.
Prezygotic Behaviors- Behavioral Isolation
Beetle mating displays show different spot patterns.
This is a DNA fingerprint exhibiting samples from a victim, two suspects, and the crime scene. Which of these DNA fragments is common to both the victim and Suspect 1?
B. A visual comparison of the gel electrophoresis results should reveal that Suspect 1 has a DNA fragment that matches victim DNA fragment B.
Prezygotic Behaviors- Temporal Isolation
Birds are active during different times of day.
This is a DNA fingerprint exhibiting samples from a victim, two suspects, and the crime scene. Which of these DNA fragments is common to both the victim and Suspect 2?
C. A visual comparison of the gel electrophoresis results should reveal that Suspect 2 has a DNA fragment that matches victim DNA fragment C.
Which of these is reverse transcriptase?
C. This is reverse transcriptase.
Why might the cricket genome have 11 times as many base pairs than that of Drosophila melanogaster?
Crickets must have more non-coding DNA.
Which of these is the viral genome?
E. HIV is an RNA virus.
Of the following anatomical structures, which is homologous to the wing of a bird?
Flipper of a cetacean
Prezygotic Behaviors- Mechanical Isolation
Flowers accomodate different insect pollinators.
Which of the following has the largest genome and the fewest genes per million base pairs?
Homo sapiens (human)
Which of the following statements about species, as defined by the biological species concept, is (are) correct? I. Biological species are defined by reproductive isolation. II. Biological species are the model used for grouping extinct forms of life. III. The biological species is the largest unit of population in which successful reproduction is possible.
I and II
A population of birds colonizes an area in which the insects upon which they feed live inside trees. -Which of the following events accounts for an observed increase in average beak size in the bird population over time?
Increased fitness of large-beaked birds, leading to natural selection
What is the function of reverse transcriptase?
It catalyzes the formation of DNA from an RNA template.
Why is golden rice pale yellow in color?
It is rich in beta-carotene. -Beta-carotene confers a yellow color on the rice.
Which is a true statement concerning genetic variation?
It must be present in a population before natural selection can act upon the population.
Postzygotic Barrier- Reduced Hybrid Viability
Lion-tiger hybrids don't reach maturity.
During drought years on the Galapagos, small, easily eaten seeds become rare, leaving mostly large, hard-cased seeds that only birds with large beaks can eat. -If a drought persists for several years, what should one expect to result from natural selection?
More small-beaked birds dying than larger-beaked birds. The offspring produced in subsequent generations have a higher percentage of birds with large beaks.
Which of the following statements about reinforcement is true?
Reinforcement is a type of natural selection. -Reinforcement is a type of natural selection called disruptive selection, which favors extreme phenotypes over intermediate phenotypes.
Homeotic genes contain a homeobox sequence that is highly conserved among very diverse species. The homeobox is the code for that domain of a protein that binds to DNA in a regulatory developmental process. -Which of the following would you then expect?
That homeotic genes are selectively expressed over developmental time.
Why is Suspect 1 considered more likely to have committed the crime than Suspect 2?
The crime scene sample contains DNA fragments from both the victim and Suspect 1. -Such a good match between crime scene DNA fragments and Suspect 1 DNA fragments strongly suggest that Suspect 1 committed the crime.
A subset of a population of birds leaves its habitat on the mainland and colonizes a nearby island. The birds, after a period of time, become reproductively isolated. The island sinks and the population of birds that lived on the island returns to itsoriginal habitat. -Which of the following statements about these bird populations is true?
The populations will not be able to interbreed because they are different species.
A large population of laboratory animals has been allowed to breed randomly for a number of generations. After several generations, 25% of the animals display a recessive trait (aa), the same percentage as at the beginning of the breeding program. The rest of the animals show the dominant phenotype, with heterozygotes indistinguishable from the homozygous dominants. -What is the most reasonable conclusion that can be drawn from the fact that the frequency of the recessive trait (aa) has not changed over time?
The two phenotypes are about equally adaptive under laboratory conditions.
Why are viruses referred to as obligate parasites?
They cannot reproduce outside of a host cell.
True or false? A flood that separates a population of frogs onto opposite sides of a lake is an example of a vicariance event that may result in allopatric speciation.
True -Allopatric speciation may occur when populations are separated geographically; this type of speciation can begin with a vicariance event, in which a geographic barrier such as water isolates a population, or a dispersal event, in which a subsetof a population migrates to a different habitat.
Prezygotic Behaviors- Habitat Isolation
Two fish species spawn at different depths.
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, genetic drift, and microevolution
Which of the various species concepts distinguishes two species based on the degree of genetic exchange between their gene pools?
biological
Which of these is a symptom of vitamin A deficiency?
blindness -Chronic vitamin A deficiency can lead to blindness.
Which of the following most correctly describes a shotgun technique for sequencing a genome?
cloning several sizes of fragments into various size vectors, ordering the clones, and then sequencing them
Ichthyosaurs were aquatic dinosaurs. Fossils show us that they had dorsal fins and tails, as do fish, even though their closest relatives were terrestrial reptiles that had neither dorsal fins nor aquatic tails. -The dorsal fins and tails of ichthyosaurs and fish are
examples of convergent evolution, and adaptations to a common environment.
In 1997, Dolly the sheep was cloned. Which of the following processes was used?
fusion of an adult cell's nucleus with an enucleated sheep egg, followed by incubation in a surrogate
What process is illustrated by this animation?
gene flow -Gene flow is the migration of individuals or gametes.
A defining characteristic of allopatric speciation is
geographic isolation.
What is the source of a viral envelope?
host cell membrane
Multigene families are
identical or similar genes that have evolved by gene duplication.
When we say that an individual organism has a greater fitness than another individual, we specifically mean that the organism
leaves more viable offspring than others of its species.
Generation-to-generation change in the allele frequencies in a population is _____.
microevolution -Generation-to-generation change in the allele frequencies in a population is the definition of microevolution.
What process is illustrated by this animation?
natural selection -This is natural selection, since environmental conditions dictate that green individuals are more likely to reproduce than are red individuals.
Recall that the Hardy-Weinberg equation is
p 2 + 2pq +q 2 = 1.
Click on the diagram to start the animation. What enzyme is responsible for the process seen here?
reverse transcriptase -Reverse transcriptase catalyzes the formation of DNA from an RNA template.
The lytic cycle of bacteriophage infection ends with the _____.
rupture of the bacterium -The bacterium ruptures and phages are released.
The genetic material of HIV consists of _____.
single-stranded RNA -The genetic material of HIV consists of two molecules of single-stranded RNA.
The unpaired nucleotides produced by the action of restriction enzymes are referred to as _____.
sticky ends -They are called sticky ends since they will "stick" to a complementary single-stranded sequence.
As a result of the lytic cycle, _____.
the host cell's DNA is destroyed -The host cell's DNA is destroyed, and ultimately, the host cell itself is destroyed in the lytic cycle.
About which of these did Darwin have a poor understanding?
the sources of genetic variations among individuals
What is the enzymatic function of restriction enzymes?
to cleave nucleic acids at specific sites
The pointer is indicating the _____. (1)
viral protein coat -The viral protein coat surrounds its genome.