Bio test

Two methods of speciation that lead to the development of separate species from a common ancestor

- Geographic isolation - Sympatric speciation isolation - Pre-zygotic reproductive isolation - Post-zygotic reproductive isolation

A particular genetic disorder is associated with a single gene with two alleles. Individuals with two recessive alleles are affected. The prevalence of the disorder is 1 in 6,600. Assuming the population is in Hardy Weinberg equilibrium, which of the following is closest to the frequency of carriers in the general population? (A) 0.00015 (B) 0.01230 (C) 0.02430 (D) 0.98770

0.0243 (C)

A particular gene has two alleles, a dominant allele A and a recessive allele a. The frequency of allele A is 0.55. If the population is in Hardy Weinberg equilibrium with respect to the gene, then what is the expected frequecy of phenotype Aa? (A) 0.203 (B) 0.303 (C) 0.405 (D) 0.495

0.495 (D)

The cladogram below shows proposed phylogenetic relationships for several vertebrates. Selected derived characteristics are indicated on the cladogram by numbered labels. Based on the information presented, which of the derived characters by alligators and manatees but not salamanders?

3

Which of these conditions should completely prevent the occurrence of natural selection in a population over time? A - The population lives in a habitat where there are no competing species present. B - The population size is large. C - The environment is changing at a relatively slow rate. D - All variation between individuals is due only to environmental factors.

All variation between individuals is due only to environmental factors (D)

On the island of Andros, mosquitofish populations live in various isolated freshwater ponds that were once united. Currently some predator ruch ponds have mosquitofish that can swim in short and fast bursts. Other ponds without predators have mosquitofish that can swim continuously for long periods of time. When placed together in the same body of water, the two types of female mosquitofish have exclusive breeding preferences. Which type of reproductive isolation operates to keep the mosquitofish isolated, even when fish from different ponds are reunited in the same body of water? A - Temporal isolation B - gametic isolation C - mechanical isolation D - behavioral isolation

Behvioural isolation (D)

Which of the following cladograms correctly represents the relationship among the group of mammals shown above

C

What is the order of the phylogenetic tree and why?

D. polylepis, A. forsteri, G. gallus, E. Africanus, E. ferus (L-R) because D. polylepis has the most differences in amino acids

A research study sampled populations of field mice annually over the course of 50 years. The population of mice was comprised of mice with light coat colour and dark coat colour, with some intermediate phenotypes present. Data from the beginning and end of the study are shown. Which of the following statements is not a conclusion supported by the data shown? A - Disruptive selection has driven the light and dark coat color phenotypes to appear in higher frequency in the population of mice. B - Natural selection is causing the light coated mice to disappear completely from the population. C - In 2005, the ecosystem experienced drought, causing a change in the habitat which led to stabilizing selection D - In 1955, the population of mice inhabited a patchy-colored environment that allowed for selection of both light and dark mice.

Disruptive selection has driven the light and dark coat color phenotypes to appear in higher frequency in the population of mice (A)

The cladogram shows shared traits among four plant taxa. Based on the cladogram, which of the following are the traits shared between ferns and pines A - Xylem only B - Seeds and wood only C - Embryo and xylem onlv D - Embryo, xylem, wood and seeds only

Embryo and Xylem only (C)

Lemurs are primates that live on the island of madagascar off the coast of Africa. Lemurs have a functional GULO gene and are able to produce ascorbic acid. However, primates that live in other places have a GLUO pseudogene and are unable to produce ascorbic acid. Which of the following best explains the genetic variation among primate species? (A) Food sources on the island of Madagascar were deficient in ascorbic acid, which caused the primates to migrate to the mainland where ascorbic acid-rich foods are more widely available. (B) Human activity on Madagascar, including poaching, drove the other primates into extinction on the island. (C) Food sources where non-Madagascar primates lived provided ample ascorbic acid in the diet, which removed the selective pressure for maintaining a functional GULO gene. (D) Food sources on the island of Madagascar were deficient in ascorbic acid, which cause lemurs to adapt by developing the ability the produce an active GULO protein.

Food sources where non-Madagascar primates lived provided ample ascorbic acid in the diet, which removed the selective pressure for maintaining a functioning GULO gene (C)

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 the average beak size in the bird population over time? A - Increased fitness of large-beaked birds, leading to natural selection B - Increased fitness of the large-beaked birds, creating a new species (C) Decreased fitness of small-beaked birds, creating a new species (D) Decreased fitness of the insects, allowing the birds to catch them more easily

Increased fitness of larger beaks lead to natural selection (A)

A researcher is studying 2 different species. Which of the following sets of observations would best support the claim that the 2 species have structural similarities as a result of convergent evolution? Genetic similarity Function of structure Form of structure A - Low Same Different B - Low Different Same C - High Same Different D - High Different Same

Low genetic similarity, Same function of structure , Different form of structure (A)

a population of finches and their relative fitness is shown in the data table below. Finches with large beaks are represented by the genotypes BB finches with medium sized beaks are represented by the genotype Bb, and finches with small size beaks are represented by the genotype bb. This particular finch population lives in an environment where large and small seeds are abundant Which of the following statements about the finches fitness is supported by the data shown in the diagram above? A - A population of all small-beaked finches will have high fitness, but not as high as the medium-beaked finches' fitness. B - Medium-beaked finches will have the lowest fitness level in this environment due to a lack of medium-sized seeds. C - Allele frequency of the large-beaked trait will continue to increase in this environment. D - The small-beaked finches are susceptible to genetic drift and will eventually decrease in number in the population

Medium beaked finches will have the lowest fitness level in this environment due to a lack of medium sized seeds (B)

Over several years, bacteria were isolated from members of a human population and tested for antibiotic resistance. The percent of bacterial isolates that were found to be antibiotic resistant is presented in the graph above for each year of the study. Which of the following conclusions is best supported by the information presented in the graph? (A) The greatest increase in antibiotic resistance occurred from the first year to the third year of study. (B) Gene flow in the population occurred at the Same rate for the entire duration of the eight-year study. (C) Because of evolution in bacterial populations occurs over millions of years, the results are due to random variations. (D) Natural selection over multiple generations is favoring antibiotic resistance in the population of bacteria.

Natural selection over multiple generations is favouring antibiotic resistance in the population of bacteria (D)

Based on morphological characteristics, the phylogenetic tree above has been developed from species I, II, III, 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? (A) Is species I the common ancestor of species II? (B) Does species I contain the greatest number of vestigial structures? (C) Are species III and IV the most closely related? (D) Should the positions of species III and IV be reversed?

Should the positions of species 3 and 4 be reversed? (D)

Scientists are interested in determining the evolution of seven lizard species found on different islands of canary island group. They isolated DNA from individuals of each species and sequenced the mitochondrial gene that encodes cytochrome b. The numbers of genetic differences between species are shown in the table below. Based on the data in the table, which of the following lizard species are most closely related? A - Species C and D B - Species E and D C - Species F and B D - Species G and A

Species E and D (B)

The graph shows the divergence of four proteins commonly found in various types of eukaryotic cells. Which of the following conclusions can be reached? A - The amino acid sequence of the fibrinopeptides has not changed drastically over the past 1.4 billion years B - The DNA sequence coding for histone H4 proteins has been highly conserved over time. C - Cytochrome c is a protein whose structure has changed little over time D - The amino acid sequence of fibrinopeptides has been highly conserved over time.

The DNA sequence coding for histone H4 proteins has been highly conserved over time (B)

in a hypothetical population of beetles, there is a wide variety of color, matching the range of coloration of the tree on which the beetles hide from predators. The graphs below illustrate four possible changes to the beetle population that result of a change in the environment due to new EPA regulations that eliminated a type of pollution that had previously been darkening the tree trunks. (A) The coloration range shifted toward more darker-colored beetles, as in diagram IV. The pollution helped the predators find the lightened tree trunks (B) The coloration in the population split into two extremes, as in diagram II. Both the lighter- and the darker-colored beetles were able to hide on the darker tree trunks. (C) The coloration range became narrower, as in diagram III. The predators selected beetles at the color extremes. (D) The coloration in the population shifted toward more darker-colored beetles, as in diagram IV. The lighter colored beetles were found more easily by the predators than were the darker-colored beetles.

The coloration in the population shifted toward more darker colored beetles were found more easily by the predators rthan were the darker colored beetles (D)

The figure shows a phylogenetic tree of various members of the order Proboscidea, which includes modern elephants. Which of the following claims is best supported by the information in the figure ? (A) The Asian and African elephants are the most closely related species shown on the tree. (B) The mammoth diverged from its most recent common ancestor with African elephants before the mastodon diverged from its most recent common ancestor with Stegodons (C) The mastodon and the Stegodon diverged from their common ancestor 2 million years ago (D) The common ancestor of the African elephant and the mastodon is the Palaeomastodon.

The common ancestor of the african elephant and the mastodon in the palaeomastodon (D)

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 of finches increased dramatically in certain populations during a drought in 1981-1987. During the drought there was a reduction in the number of plants producing thin walled seeds. The biologist discovered from 1988-1993 the average beak size declined to the sixe before 1981. The reversal in the beak size between 1988-1993 was most likely related to which events (A) A loss of food supply for the finches (B) The end of the drought (6) An increase in drought conditions (D) An increase in predators consuming finches

The end of the drought (B)

The rough skinned newt produces a toxin that can kill predators. Scientists have observed that some garter snakes can feed on the newts beacsue they have a natural resistance to the toxin. In areas where population of rough skinned newts and garter snakes interact, which of the following predictions is best supported by evolutionary theory? A - the garter snake with resistance to the toxin will successfully reproduce and pass the trait on to their offspring B - The garter snakes without resistance to the toxin will acquire resistance by increasing the rate at which they feed on the newts C - The rough skinned newts that produce low levels of toxin will also develop camouflage adaptations that allow them to hide from the garter snake D - the newts will stop making the toxin rather than continue to use energy to make a toxin that is ineffective against the garter snakes

The garter snake with resistance to the toxin will successfully reproduce and pass the trait on to their offspring (A)

On island chains, animal populations that spread from the main island to the other islands can evolve into separate species. Which of the following best explains why speciation is favoured in such a situation? A - Predators on the main island can easily migrate to follow the populations to the other islands. B - Lack of disease on the other island enables the populations to grow and change without limits. C - The climatic conditions of the islands allow the populations to breed all year long and produce several generations. D - The physical separation of the islands from the main island limits gene flow and interbreeding between the populations.

The physical separation of the islands from the main island limits gene flow and interbreeding between the populations (D)

Partial amino acid sequence for a particular protein in 3 animal species are shown below. Each of the letters in the sequence stand for an amino acid Which of the following statements best explains how these sequence data are evidence for evolution? A- All species translate the amino acid sequences of their proteins in a similar way. B - The species that are most closely related have the most similar amino acid sequences. C - Individual organisms acquire changes in their amino acid sequences over their lifetimes. D - The organisms that evolved at the same time in geologic history have identical amino acid sequences.

The species that are most closely related have the most similar amino acid sequences (B)

A large population of lab animals has been allowed to breed randomly for a number of generations. After several generations, 49% of the animals display a recessive trait (bb), the same percentage as at the beginning of the breeding program. The rest of the animals show the dominant phenotype, with heterozygotes indistinguishable from homozygous dominant. What is the most reasonable conclusion that can be drawn from the fact that the frequency of allele b has not changed over time ? A - The population is undergoing genetic drift. B - The two phenotypes are equally adaptive under laboratory conditions. C - The genotype BB is lethal. D - There has been a high rate of mutation of allele B to allele h

The two phenotypes are equally adaptive under lab conditions (B)

Goats and sheep belong to the same family but different genera. While they often live together in the same pastures, the hybrid offspring that are occasionally produced between the two species rarely survive. When such a hybrid does survive, it is usually sterile. Which of the following best explains the mechanism that maintains reproductive isolation between goats and sheep? A - Gene flow is prevented because the twospecies belong to different trophic levels and therefore do not share a food source B - Habitat isolation creates a prezygotic barrier between the two species. C - The males of one species and the females of the other species are fertile at different times. D - The two species have a different number of chromosomes, resulting in a postzygotic barrier.

The two species have a different number of chromosomes resulting in a post-zygotic barrier (D)

About 13 different species of finches inhabit the Galápagos Islands today, all descendants of a common ancestor from the South American mainland that arrived a few million years ago. Genetically, there are four distinct lineages, but the 13 species are currently classified among three genera. The first lineage to diverge from the ancestral lineage was the warbler finch (genus Certhidea). Next to diverge was the vegetarian finch (genus Camarhynchus), followed by five tree finch species (also in genus Camarhynchus) and six ground finch species (genus Geospiza). If the six ground finch species have evolved most recently, then which of these is the most logical prediction? A - The chances of hybridization between two ground finch species should be less than the chances of hybridization between two tree finch species. B - They should be limited to the six islands that most recently emerged from the sea. C - They should share fewer anatomical homologies with each other than they share with the tree finches. D - Their genomes should be more similar to each other than are the genomes of the five tree finch species.

Their genomes should be more similar to each other than are the genomes of five tree finch species (D)