In the Florida Everglades, Burmese pythons are an invasive species. They were introduced into southern Florida in 1992. These pythons feed on many of the native Florida species, establishing the pythons as the top predator in the environment. By the year 2000, their population had increased dramatically. Figures 1 and 2 display data collected by ecologists studying the results of the Burmese python invasion. Figure 1 shows counts of animals collected from nighttime road surveys in southern Florida, which are used to estimate population size. Figure 2 shows data collected from mosquitoes captured from the wild. DNA sequencing was used to identify the species of blood that the mosquitoes had in their stomachs, identifying various hosts used by the mosquitoes. The categories are labeled along the horizontal axis as follows: White-Tailed Deer, Raccoon, Coyote, Cotton Rat, and Rabbit. Each category has two bars indicated on it, which are each labeled 1996 and 2011 respectively. Each bar has an error range indicated. The vertical axis is labeled Number Observed, per 100 kilometers of road, and the numbers 0 through 3, in increments of 1, are indicated. The data for each bar is presented as follows. Note that all values are approximate. White-Tailed Deer. 1996, 2.7, plus or minus 0.3. 2011, 0.8, plus or minus 0.4. Raccoon. 1996, 1.2, plus or minus 0.2. 2011, 0. 4, plus or minus 0.2. Coyote. 1996, 1.2, plus or minus 0.4. 2011, 0.7, plus or minus 0.3. Cotton Rat. 1996, 0.65, plus or minus 0.2. 2011, 2.5, plus 0.5, minus 0.1. Rabbit. 1996, 1.7, plus or minus 0.3. 2011, 1.3, plus or minus 0.25. Figure 1. Comparison of observations of selected mammals in 1996 and 2011. The horizontal axis is labeled Year, and the years 1979 and 2016 are indicated. The vertical axis is labeled Host Use, in percent total bloodmeals, and the numbers 0 through 90, in increments of 10, are indicated. The 4 line segments are each determined by two points, and are labeled as follows: Cotton Rat, Human, White-tailed deer, and Raccoon. Each line segment is described as follows. Note that all values are approximate. All line segments begin in 1979 and end in 2016. The Cotton Rat line segment is above the Human line segment and crosses the White-tailed deer line segment. The Human line segment crosses the White-tailed deer and Raccoon line segments. The White-tailed deer line segment is above the Raccoon line segment. The line segment labeled Cotton rat begins at the point 1979, comma 15 percent, and moves upwards and to the right to end at the point 2016, comma 80 percent. The line segment labeled Human begins at the point 1979, comma 0 percent, and moves upwards and to the right to end at the point 2016, comma 10 percent. The line segment labeled White-tailed deer begins at the point 1979, comma 30 percent, and moves downwards and to the right to end at the point 2016, comma 2 percent. The line segment labeled Raccoon begins at the point 1979, comma 10 percent, and moves downwards and to the right to end at the point 2016, comma 0 percent. Figure 2. Change in host preference by Culex cedecei between 1979 and 2016. Numbers do not add up to one hundred percent because these represent a subset of all the host species. In 1996, the native Culex cedecei mosquitoes in southern Florida preferentially took blood meals from white-tailed deer and raccoons. It was predicted that changes in host population size would alter these host preferences. Additionally, it is known that cotton rats are often infected by the Everglades virus, which normally exists in animals, but is capable of infecting humans. Ecologists predict that increased feeding on cotton rats by C. cedecei may significantly increase the tendency of this virus to infect humans. Which of the following most accurately explains an impact of Burmese pythons on the Everglades community in southern Florida using the data provided?

Analysis of DNA sequences from two individuals of the same species results in a greater estimate of genetic variability than does analysis of amino acid sequences from the same individuals because

The growth curve starts at the intersection of the x and y axes and increases exponentially then flattens out halfway up the y-axis. Figure two is a graph with x-axis labeled time and y-axis labeled algae population. The growth curve starts at the intersection of the x and y axes and increases exponentially then flattens out halfway up the y-axis. Phosphate is added after the growth curve flattens out, then increases exponentially again and flattens out at the top of the y-axis. Figure I shows the growth of an algal species in a flask of sterilized pond water. If phosphate is added as indicated, the growth curve changes as shown in Figure II. Which of the following is the best prediction of the algal growth if nitrate is added instead of phosphate?

A number of different phylogenies (evolutionary trees) have been proposed by scientists. These phylogenies are useful because they can be used to

LAC OPERON STRUCTURE The L A C operon has a region labeled Regulatory Gene that contains loci P subscript 1 and l a c 1. The L A C operon has a 2nd, separate region that contains five loci, in order from left to right on the DNA strand, P subscript l a c, operator, l a c Z, l a c Y, l a c A. The functions of the loci of the lac operon shown in the diagram are described in the table below. Functions of the loci of the lac operon Locus Function PI Attachment site for RNA polymerase lacI Encodes a repressor protein that prevents transcription of the structural genes of the lac operon Plac Attachment site for RNA polymerase Operator Binding site for the repressor protein lacZ Encodes beta-galactosidase, the enzyme that digests lactose to glucose and galactose lacY Encodes lactose permease, the channel through which lactose moves into the cell lacA Encodes galactoside transacetylase The diagram above represents a segment of the E. coli chromosome that contains the lacI gene and part of the lac operon, a coordinately regulated set of genes that are required for the metabolism of lactose. The presence of lactose, which causes the repressor to be released from the operator, results in increased transcription of the lac operon. Which of the following is the most likely consequence of a mutation at the operator locus that prevents binding of the repressor protein?

Population ecologists are typically not very interested in the actual number of individuals in a population at a given time. What they are really interested in is

Individuals of a particular species of ground beetle are either light tan or dark brown. Light-tan beetles are predominant in habitats with light-colored sandy soils, and dark-brown beetles are predominant in habitats with dark-colored loam soils. In an experiment designed to determine the survival rates of light-tan beetles and dark-brown beetles in different habitats, 500 light-tan beetles and 500 dark-brown beetles were released in each of four habitats. Each beetle had been marked with a small spot of red paint on the underside of its abdomen before it was released. One week after the beetles had been released, any marked beetles that could be found were recaptured. The results are presented in the table below. It is assumed that differences in the numbers of beetles recaptured are directly related to differences in survival rates. Columns 2 thru 5 have 2 sub-columns each. The top row contains the column labels: columns one is blank; Column two: Habitat 1: Sandy soil, no insectivorous birds present. Column three: Habitat 2: Sandy soil, insectivorous birds present. Column four: Habitat 3: Loam soil, no insectivorous birds present. Column five: Loam soil, insectivorous birds present. From top to bottom the data is as follows: Row two: Color of Beetle: Habitat 1, sub-column one, Light tan; sub-column two, Dark brown. Habitat 2, sub-column one, Light tan; sub-column two, Dark brown. Habitat 3, sub-column one, Light tan; sub-column two, Dark brown. Habitat 4, sub-column one, Light tan; sub-column two, Dark brown. Row three: Number Released: Habitat 1, sub-column one, five hundred; sub-column two, five hundred. Habitat 2, sub-column one, five hundred; sub-column two, five hundred. Habitat 3, sub-column one, five hundred; sub-column two, five hundred. Habitat 4, sub-column one, five hundred; sub-column two, five hundred. Row four: Number Recaptured: Habitat 1, sub-column one, one hundred thirty; sub-column two, one hundred fourteen. Habitat 2, sub-column one, one hundred twenty-three; sub-column two, twenty-two. Habitat 3, sub-column one, sixty-five; sub-column two, seventy-four. Habitat 4, sub-column one, thirteen; sub-column two, eighty-seven. Which of the following can be inferred from the data in the table?

Sickle-cell anemia results from a point mutation in the HBB gene. The mutation results in the replacement of an amino acid that has a hydrophilic R-group with an amino acid that has a hydrophobic R-group on the exterior of the hemoglobin protein. Such a mutation would most likely result in altered

Tay-Sachs disease is a rare inherited disorder caused by an autosomal recessive allele of the HEXA gene. Affected individuals exhibit severe neurological symptoms and do not survive to reproductive age. Individuals who inherit one copy of the allele (Tay-Sachs carriers) typically show no symptoms of the disorder. The frequencies of Tay-Sachs carriers in the general population of North America and in three different subpopulations are presented in the table. For general population the frequency is 0.004. For subpopulation 1 the frequency is 0.037. For subpopulation 2 the frequency is 0.035. For subpopulation 3 the frequency is 0.020. Based on the information presented, which of the following best explains the difference in phenotype between Tay-Sachs carriers and homozygous recessive individuals?

Iron is an essential nutrient that is acquired by organisms from the environment. When intracellular levels of iron are relatively high, living cells synthesize an iron-storage protein called ferritin. The induction of ferritin synthesis by iron was investigated in rats. Figure 1 shows the results of an experiment in which cellular levels of ferritin protein were measured in the presence or absence of iron and actinomycin D, a drug that inhibits transcription. Figure 2 shows the results of an experiment in which cellular levels of ferritin protein were measured in the presence or absence of iron and cycloheximide, a drug that inhibits translation. The horizontal axes are labeled Treatment, and the vertical axes are labeled Relative Protein Level. Five tick marks appear on the vertical axis, from bottom to top, the first tick mark is labeled zero, the third tick mark is labeled one point zero, and the fifth tick mark is labeled two point zero. The graph on the left is labeled Figure one. Ferritin Protein Levels. Four vertical bars appear along the horizontal axis, and the presence or absence of Iron and Actinomycin D is indicated above each bar. The data in the graph, from left to right, are as follows: Bar 1: Absence of Iron; Absence of Actinomycin D; Relative Protein Level one point zero. Bar 2: Presence of Iron; Absence of Actinomycin D; Relative Protein Level two point two. Bar 3: Absence of Iron; Presence of Actinomycin D; Relative Protein Level zero point nine. Bar 4: Presence of Iron; Presence of Actinomycin D; Relative Protein Level two point zero. The graph on the right is labeled Figure 2. Ferritin Protein Levels. Four vertical bars appear along the horizontal axis, and the presence or absence of Iron and Cycloheximide is indicated above each bar. The data in the graph, from left to right, are as follows: Bar 1: Absence of Iron; Absence of Cycloheximide; Relative Protein Level one point zero. Bar 2: Presence of Iron; Absence of Cycloheximide; Relative Protein Level two point five. Bar 3: Absence of Iron; Presence of Cycloheximide; Relative Protein Level zero point nine. Bar 4: Presence of Iron; Presence of Cycloheximide; Relative Protein Level zero point nine. Which of the following biotechnology approaches could be used to identify ferritin mRNA in a sample of total cellular RNA?