ap classroom ch. 26 ap bio
The brown anole (Anolis sagrei) is a species of lizard native to Cuba that has been introduced into the southeastern United States. The range of brown anoles in the United States has been expanding, and they are now competing with native green anoles (Anolis carolinensis). Some of the characteristics of the green and brown anoles are shown in Table 1. A cladogram showing the relationships between some anole species is shown in Figure 1. Which of the following is the outgroup in the cladogram shown in Figure 1?
A. carolinensis Based on the cladogram, A. carolinensis is more distantly related to all of the other species in the cladogram than the other species are related to each other.
The brown anole (Anolis sagrei) is a species of lizard native to Cuba that has been introduced into the southeastern United States. The range of brown anoles in the United States has been expanding, and they are now competing with native green anoles (Anolis carolinensis). Some of the characteristics of the green and brown anoles are shown in Table 1. A cladogram showing the relationships between some anole species is shown in Figure 1. Based on Figure 1, which of the following would provide the strongest evidence to support a claim that A. valencienni and A. lineatopus are the two anole species most closely related to A. sagrei ?
Analyzing homologous DNA sequences among the species The rate that mutations appear in the genomes of species is relatively constant, and therefore the number of differences between two species can serve as a molecular clock to measure how long ago species diverged.
Cods and icefish are the only orders of fish that include species that produce antifreeze proteins in their blood. Based on the cladogram in Figure 1, which of the following scenarios describes the most likely evolutionary history of antifreeze protein synthesis in fish?
Antifreeze proteins arose twice, once in the cod lineage and once in the icefish lineage. This is an example of convergent evolution. Cods and icefish do not share a recent common ancestor. Additionally, none of the other fish to which icefish are more closely related produce antifreeze proteins. This suggests that the presence of antifreeze proteins evolved separately in the cods and icefish lineages, and similar environmental conditions selected for the proteins to continue to be produced in future generations.
Based on morphological characteristics, the phylogenetic tree above has been developed for species I, II, III, 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 III and IV the most closely related?
The cladogram shown below depicts an accepted model of the evolutionary relationships among selected species. The amino acid at position 104 in the beta-hemoglobin protein for each of these four organisms is listed below. 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
The TAS2R38 gene encodes a receptor protein that influences the ability to taste bitterness. The gene has two alleles: a dominant, wild-type allele that enables an individual (taster) to taste bitterness and a recessive, mutant allele that interferes with the ability of an individual (nontaster) to taste bitterness. Three single nucleotide mutations in the coding region of the TAS2R38 gene are associated with the nontaster allele. The nucleotides present at the three positions are shown in the table below. A cladogram representing the evolutionary relatedness of selected primates is shown below. Which of the following conclusions is supported by the data?
Bonobos are more closely related to humans than to gorillas because bonobos and humans share a more recent common ancestor than bonobos and gorillas do.
The brown anole (Anolis sagrei) is a species of lizard native to Cuba that has been introduced into the southeastern United States. The range of brown anoles in the United States has been expanding, and they are now competing with native green anoles (Anolis carolinensis). Some of the characteristics of the green and brown anoles are shown in Table 1. A cladogram showing the relationships between some anole species is shown in Figure 1. Based on the cladogram in Figure 1, which of the following conclusions about the evolution of the anole species is most reasonable?
Each species evolved as a result of different selective pressures. Different populations of anoles likely experienced different selective pressures, which selected for different traits.
The table above shows derived characters for selected organisms. Based on the information in the table, which of the following cladograms best represents the evolutionary relationships among the organisms?
From left to right Fish Amphibians Crocodilians with branch (Birds) Mammals (underneath all)
The gene encoding the catalytic subunit of cytochrome c oxidase (MT-CO1) is found in the mitochondria of all animals. The gene evolves rapidly and is often used to determine evolutionary relationships among species. Table 1 shows DNA sequence differences among four animal species (II, IIII, IIIIII, and IVIV). Which of the following cladograms best represents the evolutionary relationships among the four species?
From left to right II I with branch coming off (III) IV (underneath all others) extra explanation: The cladogram indicates that species II split off early in the evolutionary lineage and that species IV split off prior to the separation of species II from species III. The cladogram is supported by the data in Table 1 because the greatest percent difference in the sequence of the MT−CO1 gene is between species IIII and each of the other species. Additionally, the lowest percent difference is between species II and III.
Data regarding the presence (+) or absence (-) of five derived traits in several different species are shown in the table below. Which of the following cladograms provides the simplest and most accurate representation of the data in the table?
From left to right Y W with a branch coming off it (V) Z X (long branch underneath all others)
Five new species of bacteria were discovered in Antarctic ice core samples. The nucleotide (base) sequences of rRNA subunits were determined for the new species. The table below shows the number of nucleotide differences between the species. Which of the following phylogenetic trees is most consistent with the data?
From top to bottom 3 4 2 1 5 It demonstrates the ability to select the phylogenetic tree that correctly represents evolutionary history and speciation from the data set. The data indicate that species 5 is not closely related to the others and that 3 and 4 are very closely related. This cladogram incorporates those differences as well as the close relationship between 1 and 2.
The three-spined stickleback (Gasterosteus aculeatus) is a small fish found in both marine and freshwater environments. Marine stickleback populations consist mainly of individuals with armor-like plates covering most of their body surface (completely plated). Approximately 10,000 years ago, some marine sticklebacks colonized freshwater environments. After many generations in the freshwater environments, the freshwater stickleback populations lacked the armor plating (low plated) typical of marine stickleback populations. Over the period between 1957 and 2005, one freshwater population, in Lake Washington, a lake in a coastal region of the northwestern United States, changed from having a majority of individuals of the low-plated phenotype to having more individuals of the completely-plated phenotype than of the low-plated phenotype. Figure 1 shows the distribution of plated phenotypes in Lake Washington sticklebacks at four time points between 1957 and 2005. A single gene, ectodysplasin (EDA), is thought to be responsible for the variation in the number of armor plates in sticklebacks. Figure 2 shows a phylogenetic tree constructed by comparing DNA sequences of the EDA gene from a number of stickleback populations with low-plated or completely plated phenotypes. Figure 3 shows a phylogenetic tree constructed by comparing the sequences of 25 genes that were randomly selected from the same populations as shown in Figure 2. In both figures, shaded populations display the completely plated phenotype. The phylogenetic trees in Figures 2 and 3 depict two different phylogenies of the same populations of sticklebacks. Which of the following questions will best help determine which tree represents the most accurate phylogeny?
Is the EDA gene as representative of the differences between the populations as the 25 random genes that were examined for Figure 3?
The table above shows the presence (+) or absence (-) of three different derived characters (vascular tissue, seeds, and flowers) for several selected plant species. The cladogram below was created based on the information in the table to represent groups of related species. The presence of the derived characters is indicated with arrows. Group IV of the cladogram most likely includes which of the following species?
P and S only
Scientists are interested in determining the evolution of seven lizard species found on different islands of the Canary Island group. They isolated DNADNA 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?
Species E and Species D These species have the fewest mitochondrial genetic differences.
To determine the evolutionary history and relationships among organisms, scientists gather evidence from a wide variety of sources including paleontology, embryology, morphology, behavior, and molecular biology. A phylogenetic tree of vertebrates is shown. Which of the following statements is most consistent with the phylogenetic tree shown?
The common ancestor of reptiles, birds, and mammals produced amniotic eggs.
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 ?
The common ancestor of the African elephant and the mastodon is the Palaeomastodon. If the lineages of the African elephant and the mastodon are traced back until they intersect, the species at the point of intersection is the Palaeomastodon.
Researchers investigated the habitat preferences of two species of garter snakes, Thamnophis sirtalis and Thamnophis atratus. To create a choice chamber, the researchers built a meshed enclosure and positioned one end of the enclosure at the edge of a small pond. Zone I of the enclosure was located in the water, whereas zone IV of the enclosure was located 2-3 meters away from the water, as represented in the figure below. Snakes inside the enclosure were able to move freely between zones. In a series of experiments, the researchers introduced a single snake into zone IV of the enclosure at 7:00 A.M. The researchers recorded the location of the snake at six time points throughout the day. In a related experiment, the researchers introduced two snakes, one of each species, into the enclosure at the same time and observed the location of each of the two snakes at the same six time points as before. The researchers repeated both the one-snake and two-snake experiments using different individual snakes of each species. The results are presented in the table. Both species of garter snakes prey on the California newt, Taricha torosa, a small amphibian that produces a potent neurotoxin (TTX) in its skin. However, neither species of garter snake is affected by TTX. The resistance to TTX is associated with mutations in the SCN4A gene. Which of the following best supports a claim that TTX resistance arose independently in T. atratus and T. sirtalis ?
The two species of snakes have different genetic mutations in the SCN4A gene.
Ascorbic acid (vitamin C) is an organic molecule necessary for the health of plants and animals. The majority of animals, including most mammals, synthesize ascorbic acid from organic precursors, but some primates are unable to synthesize ascorbic acid and must instead acquire it from dietary sources, such as certain fruits and vegetables. The L-gulonolactone oxidase (GULO) gene encodes an enzyme that catalyzes a required step in the biosynthesis of ascorbic acid. Most mammals carry a functional copy of the GULO gene, but some primates carry only a GULO pseudogene, which is a nonfunctional variant. A comparison of GULO genes and GULO pseudogenes from different animals can provide insight into the evolutionary relatedness of the animals. In Table I, selected members of some mammalian groups are listed, along with an indication of their ability to synthesize ascorbic acid. Table II shows an alignment of amino acid coding sequences from homologous regions of the GULO genes and GULO pseudogenes of the organisms listed in Table I. Figure 1 represents the universal genetic code. Which of the following phylogenetic trees best illustrates (with the X) the point at which the mutation in the GULO gene most likely occurred during the evolutionary history of these organisms?
from top to bottom human (has X before it) chimpanzee (has X before it) orangutan (has X before it) lemur nonprimate
