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To investigate the influence of predation risk on ray behavior, a student observed and counted the large marine animals swimming in a shallow, nearshore section of a coral reef ecosystem. The time of each observation was recorded relative to the time of high tide. The student noted that at low tide, when the water level is low, many of the large animals are forced out of the study area and into the deeper waters of the outer reef. During high tides, when the water level is high, the large animals are able to reenter the study area. Over a three-day period, the student observed a total of 604 individual rays belonging to three species: cowtail rays, giant shovelnose rays, and black stingrays. For each ray that was sighted, its body length was estimated and its status as either alone (ungrouped) or found with other rays (grouped) was noted. Occasionally, rays were observed sifting through the sandy substrate of the study area to capture food items such as molluscs and crustaceans. In one instance, an injured ray with bite marks that were likely sustained in a shark attack was sighted. In addition to the rays, the student observed lemon sharks (n = 46) and blacktip reef sharks (n = 39). The results of the study are presented in the figures below. The horizontal axis is labeled “Mean Body Length, in meters,” and the numbers 0 through 1.5, in increments of 0.5, are indicated. The vertical axis gives the three categories of the graph, each of which contains two subcategories. The three categories are Cowtail Rays, Giant Shovelnose Rays, and Black Stingrays. The subcategories are Ungrouped and Grouped. The data are presented as follows. Note that all values are approximate. Cowtail Rays: Ungrouped have a mean body length of 1.5 meters, and the error bar spans plus or minus 0.03. Grouped have a mean body length of 1.35 meters, and the error spans plus or minus 0.05. Giant Shovelnose Rays: Ungrouped have a mean body length of 1.6 meters, and the error bar spans plus or minus 0.04. Grouped have a mean body length of 1.35 meters, and the error spans plus or minus 0.08. Black Stingrays: Ungrouped have a mean body length of 1.4 meters, and the error bar spans plus or minus 0.02. Grouped have a mean body length of 1.3 meters, and the error spans plus or minus 0.05. Figure 1. Comparison of mean body lengths of the grouped and ungrouped rays that were observed in a nearshore section of a coral reef ecosystem. Error bars represent 2SEx̄ The graph shows the mean number of rays per group in the study area relative to stages of the tide cycle. The horizontal axis is labeled “Time Relative to High Tide, in hours,” and the numbers negative 3 through positive 1, in increments of 1, are indicated. The vertical axis is labeled “Mean Group Size,” and the numbers 0 through 6, in increments of 1, are indicated. The line is composed of five points connected by line segments, and error bars are shown for each point. The five points are listed as follows. Note that all values are approximate. Point 1. Time relative to High Tide, negative 3 hours. Mean Group Size, 0.9 plus or minus 0 point 4. Point 2. Time relative to High Tide, negative 2 hours. Mean Group Size, 2 point 5 plus or minus 0 point 2. Point 3. Time relative to High Tide, negative 1 hours. Mean Group Size, 4 point 4 plus or minus 0 point 9. Point 4. Time relative to High Tide, 0 hours. Mean Group Size, 4 point 6 plus or minus 0 point 1. Point 5. Time relative to High Tide, positive 1 hours. Mean Group Size, 3 point 6 plus or minus 0 point 3. Figure 2. Mean numbers of rays per group in the study area at different stages of the tide cycle. High tide occurs at T = 0 hours. The graph shows the relative proportions of rays in groups at different stages of the tide cycle. A key indicates that three different lines represent giant shovelnose rays or black stingrays or cowtail rays. The horizontal axis is labeled “Time relative to High Tide, in hours,” and the numbers negative 3 through positive 1, in increments of 1, are indicated. The vertical axis is labeled “Relative Proportion of Rays Found in Groups” and has an arrowhead at the top end. The line for each type of ray is composed of five points connected by line segments, and error bars are shown for most points. The data for each time point are as follows. Point 1. Time relative to High Tide, negative 3 hours. The proportion of each type of ray is similar, and there are very few of each type. Point 2. Time relative to High Tide, negative 2 hours. The number of cowtail rays increased slightly, and there are about twice as many giant shovelnose rays and six times as many black stingrays as cowtail rays. Error bars are shown for only the cowtail rays and giant shovelnose rays. The upper end of the cowtail rays error bar touches the lower end of the giant shovelnose rays error bar. Point 3. Time relative to High Tide, negative 1 hours. The number of cowtail rays is double the number at negative two hours, and there are about three times as many giant shovelnose rays and five times as many black stingrays as cowtail rays. Error bars are shown for each point. The error bar range for the cowtail rays is very narrow; the error bars for the black stingrays and giant shovelnose rays are broad, but do not overlap. Point 4. Time relative to High Tide, 0 hours. The number of cowtail rays is about three quarters the number at negative one hours, and there are about twelve times as many giant shovelnose rays and nine times as many black stingrays as cowtail rays. The error bar range for the cowtail rays is very narrow; the error bars for the black stingrays and giant shovelnose rays are broad, and the upper end of the black stingrays error bar touches the lower end of the giant shovelnose rays error bar. Point 5. Time relative to High Tide, positive 1 hours. The number of cowtail rays is just slightly greater than the number at 0 hours, and there are about seven times as many giant shovelnose rays and five times as many black stingrays as cowtail rays. The error bar range for the cowtail rays is very narrow; the error bars for the black stingrays and giant shovelnose rays are broad, and the upper end of the black stingrays error bar touches the lower end of the giant shovelnose rays error bar. Figure 3. Relative proportions of rays in groups at different stages of the tide cycle for each of the three different populations. High tide occurs at T = 0 hours. The graph shows the mean numbers of lemon sharks and blacktip reef sharks at different stages of the tide cycle. A key indicates that one line represents lemon sharks, and the other line represents blacktip reef sharks. The horizontal axis is labeled “Time Relative to High Tide, in hours,” and the numbers negative 3 through positive 1, in increments of 1, are indicated. The vertical axis is labeled “Mean Number of Sharks,” and the numbers 0 through 10, in increments of 1, are indicated. The two curves are composed of five points connected by line segments. No error bars are shown. The five points of each line are listed as follows. Note that all values are approximate. The following five points are indicated on the line representing lemon sharks. Point 1. Time relative to High Tide, negative 3 hours. Mean Number of Sharks, 4.2. Point 2. Time relative to High Tide, negative 2 hours. Mean Number of Sharks, 9. Point 3. Time relative to High Tide, negative 1 hours. Mean Number of Sharks, 1.5. Point 4. Time relative to High Tide, 0 hours. Mean Number of Sharks, 0. Point 5. Time relative to High Tide, positive 1 hours. Mean Number of Sharks, 1. The following five points are indicated on the line representing blacktip reef sharks. Point 1. Time relative to High Tide, negative 3 hours, Mean Number of Sharks, 0.3. Point 2. Time relative to High Tide, negative 2 hours, Mean Number of Sharks, 0.3. Point 3. Time relative to High Tide, negative 1 hour, Mean Number of Sharks, 4. Point 4. Time relative to High Tide, 0 hours, Mean Number of Sharks, 7. Point 5. Time relative to High Tide, positive 1 hour, Mean Number of Sharks, 9. Figure 4. Mean numbers of lemon sharks and blacktip reef sharks in the study area at different stages of the tide cycle. High tide occurs at T = 0 hours. Based on the results of the study, which of the following is the most likely connection between behavior and evolutionary fitness in a nearshore coral reef environment?

Figure 1 illustrates a model of the molecules involved in DNA replication and their placement relative to each other. The D N A is coiled on the left side of the figure but separated into two single strands on the right side. The right end of the upper separated strand is labeled 3 prime, and the left end of the same strand, in the coiled region, is labeled 5 prime. The right end of the lower separated strand is labeled 5 prime, and the left end of the same strand, in the coiled region, is labeled 3 prime. A circle labeled Topoisomerase is wrapped around the coiled portion of the D N A close to the single stranded region on the right. A triangle labeled Helicase is positioned in the single stranded region at the point where the coiled strands are separating. A very short segment of R N A is bound to the far right end of the upper separated single strand of D N A. Figure 1. Model including molecules involved in DNA replication Which of the following correctly explains where DNA replication will begin on the strand oriented 5’→3′, reading from left to right?

Figure 1 shows some relevant details of a model of how a deoxynucleotide, in this case dTMP, is added to a growing strand of DNA. A D N A template that consists of nine nucleotides is shown. Five nucleotides have already been added to the complementary strand that is growing from left to right along the template. The left end of the growing strand is labeled 5 prime, and the right end is labeled 3 prime. The left end of the template strand is labeled 3 prime, and the right end is labeled 5 prime. An incoming d T T P has three phosphate groups. Arrows indicate that the two outermost phosphate groups split off as the d T M P with the remaining phosphate group is about to join to the 3 prime end of the growing strand. Figure 1. Model showing details of adding a deoxythymidine monophosphate (dTMP) nucleotide to a growing strand of DNA The features of this model provide evidence for which explanation of why all growing strands are synthesized in a 5′ to 3′ direction?

In a transformation experiment, a sample of E. coli bacteria was mixed with a plasmid containing the gene for resistance to the antibiotic ampicillin (ampr). Plasmid was not added to a second sample. Samples were plated on nutrient agar plates, some of which were supplemented with the antibiotic ampicillin. The results of E. coli growth are summarized below. The shaded area represents extensive growth of bacteria; dots represent individual colonies of bacteria. Wild type E. coli are plated on plates 1 and 2, and E. coli with plasmid containing the ampicillin resistance gene is plated on plates 3 and 4. Plate 1 has no ampicillin,and is shaded representing extensive growth of bacteria. Plate 2 has ampicillin and is white with no colonies. Plate 3 has no ampicillin and is shaded representing extensive growth of bacteria. Plate 4 has ampicillin and has a dozen dots representing individual colonies of bacteria. In a second experiment, the plasmid contained the gene for human insulin as well as the ampr gene. Which of the following plates would have the highest percentage of bacteria that are expected to produce insulin?

Rr. Robert Hazen has worked to develop a hypothesis that explains the origin of life on Earth. His work has focused on hydrothermal vents, which are cracks in the ocean floor. Water heated by molten rock beneath the crust escapes from these vents at very high temperatures, producing hot, high‑pressure environments at the vents on the ocean floor. In order to provide evidence that these vents may be areas where life originated, which of the following states a null hypothesis Hazen might have used to begin his research?

The horizontal axis is labeled “Egg Incubation Temperature, in degrees Celsius,” and the numbers 20 and 40 are indicated. The vertical axis is labeled “Proportion of Hatchlings That Are Male,” and the numbers 0 through 1, in increments of 0 point 5, are indicated. The three curves are labeled “Green Turtles”, “Crocodilians”, and “Lizards”. The curve labeled “Green Turtles” begins at 20 degrees Celsius and 1 male hatchling. It moves slightly downward and to the right at first until it reaches approximately 27 degrees Celsius and 0 point 9 5 male hatchling. It then descends steeply until it reaches approximately 33 degrees and 0 point 0 5 male hatchling. At this point it moves slightly downward and to the right until it ends at approximately 40 degrees Celsius and 0 male hatchlings. The curve labeled “Lizards” begins at 20 degrees Celsius and 0 male hatchlings. It moves slightly upward and to the right at first until it reaches approximately 27 degrees Celsius and 0 point 0 5 male hatchling. It then rises steeply until it reaches approximately 33 degrees and 0 point 9 5 male hatchling. At this point it moves slightly upward and to the right until it ends at approximately 40 degrees Celsius and 1 male hatchling. The curve labeled “Crocodilians” begins at 20 degrees Celsius and 0 male hatchling. It moves horizontally to the right at first until it reaches approximately 23 degrees Celsius and 0 point 0 male hatchlings. It then curves steeply upward and to the right until it reaches approximately 30 degrees and 1 male hatchling. At his point it curves steeply downward and to the right until it reaches approximately 37 degrees Celsius and 1 male hatchling. It continues horizontally until it ends. The Green Turtles curve intersects the Lizards curve at 30 degrees Celsius and 0 point 5 male hatchling. The Crocodilians curve intersects the Green Turtles curve at approximately 27 degrees and 0 point 9 male hatchling, and it intersects the Lizards curve at approximately 37 degrees and 0 point 9 male hatchling. The graph above represents the proportions of hatchlings of certain types of reptiles that are male at different egg incubation temperatures. Which of the following claims is best supported by the data?

Stickleback fish are found in both marine and freshwater habitats. The marine fish have no scales but have hardened, armorlike plates along their sides. The plates are thought to protect sticklebacks from certain predators. In the late 1980s, sticklebacks from a marine population colonized Loberg Lake, a freshwater lake in Alaska. Starting in 1990, researchers sampled fish from the lake every four years and recorded the armor-plate phenotypes of the male sticklebacks in each sample. The armor-plate phenotypes were categorized as either complete (plates extending from head to tail), partial (plates extending from head to abdomen), or low (a few plates near the head only). The results are shown in the table below. ARMOR-PLATE VARIATION IN THE STICKLEBACK POPULATION OF LOBERG LAKE Percent of Males in the Sample with Each Armor-Plate Phenotype Year Low Partial Complete 1990 1% 2% 97% 1994 45% 14% 41% 1998 58% 16% 26% 2002 76% 15% 9% 2006 90% 6% 4% To evaluate the reliability of the results, it would be best to know which of the following?

Genetic engineering techniques can be used when analyzing and manipulating DNA and RNA. Scientists used gel electrophoresis to study transcription of gene L and discovered that mRNA strands of three different lengths are consistently produced. Which of the following explanations best accounts for this experimental result?

A group of students summarized information on five great extinction events. Five Great Extinction Events Mass Extinction Time of Extinction Organisms Greatly Reduced or Made Extinct End of the Ordovician period 443 million years ago Trilobites, brachiopods, echinoderms, and corals End of the Devonian period 354 million years ago Marine families on tropical reefs, corals, brachiopods, and bivalves End of the Permian period 248 million years ago Trilobites, mollusks, brachiopods, and many vertebrates End of the Triassic period 206 million years ago Mollusks, sponges, marine vertebrates, and large amphibians End of the Cretaceous period 65 million years Ammonites, dinosaurs, brachiopods, bivalves, and echinoderms The students are sampling a site in search of fossils from the Devonian period. Based on the chart, which of the following would be the most reasonable plan for the students to follow?

Competition for food would probably be most severe between two