Unit 8 Review 𖦹⋆｡°✩ Flashcards
Scientists are studying the two primary vocalizations made by Belding’s ground squirrels (Urocitellus beldingi). The trill call consists of a series of medium-pitched notes given rapidly, while the whistle call consists of a single high-pitched note. The objective of the experiment is to determine the function of each vocalization. Recordings of the calls were played to four different groups of squirrels, and the response of each individual squirrel was documented. The responses are summarized in Table 1. Which of the following correctly identifies the dependent variable and the independent variable for the experiment?
A. The independent variable is the percent of squirrels responding, and the dependent variable is the type of alarm call.
B. The independent variable is the percent of squirrels responding, and the dependent variable is the type of response.
C. The independent variable is the group of squirrels, and the dependent variable is the percent of squirrels responding.
D. The independent variable is the type of alarm, and the dependent variable is the percent of squirrels responding.
✩CORRECT ANSWER FOR 8.1, 1✩
D
A group of biologists were investigating the effects of light color on phototropism (growing toward the light source) in tomato plants. Four groups of tomato plants were grown in the same greenhouse under identical conditions. Each group was then placed in a different room, each room having a different color of light, exposed to that single color of light from different directions for one week at a time. After each week, the biologists counted the number of tomato plants in the groups that were showing evidence of phototropism. The results are summarized in Table 1. Which of the following correctly identifies the dependent and independent variables in this experiment?
A. The color of the light is the dependent variable, and the percentage of plants showing phototropism is the independent variable.
B. The percentage of plants showing phototropism is the dependent variable, and the color of the light is the independent variable.
C. The direction of the light is the dependent variable, and the percentage of plants showing phototropism is the independent variable.
D. The color of the light is the dependent variable, and the direction of the light is the independent variable.
✩CORRECT ANSWER FOR 8.1, 2✩
B
Quorum sensing is a form of cell-to-cell communication used by some bacterial species to regulate their behavior and population size. Staphylococcus aureus uses quorum sensing to activate its virulence genes once its population reaches a minimum size. Virulence refers to the ability of a pathogen to cause disease. S. aureus secretes autoinducing peptide (AIP), which binds to the AgrC receptor on the bacterial cell membrane. When the S. aureus population is sufficiently large and produces enough AIP, this concentration activates AgrC and stimulates a signal cascade resulting in the production of hemolysin, a toxin used to attack the host organism. In order to lessen the impact of the toxin produced by an S. aureus infection on patients, scientists created AIP mimics intended to act as competitive inhibitors of AIP-AgrC binding at the cell surface. Identify the experimental design that would determine which AIP mimic would most effectively inhibit the production of hemolysin toxin.
A. Grow S. aureus in separate culture media containing one AIP mimic each and measure the amount of AIP mimic transported into the cells. The most effective AIP mimic will be absorbed the fastest.
B. Grow S. aureus in separate culture media containing one AIP mimic each and measure the production of hemolysin toxin. The most effective AIP mimic will be in the culture producing the lowest amount of hemolysin.
C. Grow S. aureus in culture media containing hemolysin and measure the production of AIP
mimic in response to hemolysin intake. The most effective AIP mimic will be produced in the highest amount.
D. Grow S. aureus in separate culture media containing one AIP mimic each and measure the amount of live cells in each culture. The most effective AIP mimic will be the one that killed the most S. aureus.
✩CORRECT ANSWER FOR 8.1, 3✩
B
A population of 250 birds inhabit a canopy of a tropical rain forest that has a carrying capacity of 400 birds. What is the maximum population growth rate (rmax) if the population grows to 283 in one year?
A. 0.12
B. 0.13
C. 0.35
D. 0.39
✩CORRECT ANSWER FOR 8.3, 1✩
C
A fish population of 250 in a pond has a maximum annual rate of increase of 0.8. If the carrying capacity of the bond is 1500 for this species, what is the expected population size after one year?
A. 167
B. 417
C. 450
D. 500
✩CORRECT ANSWER FOR 8.3, 2✩
B
The population of Japanese sika deer in central Japan was determined each year from 2005 to 2014. The sika deer population underwent logistic growth starting at 26,000 deer in 2005 and stabilized at 58,000 deer between 2012 and 2014. Based on these data, the rmax for the population was determined to be 0.57. Central Japan contains a variety of habitats, including forests and grasslands. Sika deer benefit from the resources in grasslands more than forests; if deforestation occurred, producing more grasslands in the region, the carrying capacity for sika deer population would increase. What would the population size of sika deer be one year after the carrying capacity increased to 70,000 as a result of deforestation? Assume rmax does not change.
A. The population would grow to 70, 000 deer in a year, because they would occupy the entire environmental niche.
B. The population would grow to 91, 060 deer in a year, but then they would die off from a lack of resources.
C. The population would grow to 63, 667 deer in a year, and the growth rate would decrease the following year.
D. The population would remain at 58, 000 deer, since it had already stabilized
✩CORRECT ANSWER FOR 8.3, 3✩
C
✩WAITING ON 8.4 QUIZ RESULTS✩
Researchers studied the diversity of macroscopic invertebrates in different areas of watershed ecosystems. They collected samples from 58 sites along 11 streams in the same geographical area. Their data were classified by stream type and can be found in Figure 1. The stream-type classifications range from the perennial stream type, which always has water, to the intermittent stream type, which is dry for more than nine months during the year. Which of the stream types had a statistically lower macroscopic invertebrate species diversity than the seasonal streams?
A. Transitional streams only
B. Intermittent streams only
C. Perennial and intermittent streams only
D. Transitional and intermittent streams only
✩CORRECT ANSWER FOR 8.5, 1✩
B
Interactions among populations determine how they access resources within a community. In Costa Rica, two different species of mites, Rhinoseius colwelli and Rhinoseius richardsoni, exhibit a high degree of interspecies competition. Both mite species live within the flowers of plants, and adult male mites tend to kill mites if they belong to a different species. An experiment was carried out to determine whether these aggressive interactions have resulted in niche partitioning by R. colwelli and R. richardsoni, of different flower species, with each mite species living in different plant species. The results are summarized in Figure 1. Which of the following is an accurate interpretation of the data in Figure 1 ?
A. R. richardsoni is found significantly more frequently on Species 4 compared to Species 3.
B. R. colwelli is found significantly more frequently on Species 1 compared to Species 2.
C. R. richardsoni is found significantly more frequently on Species 3 and Species 4 compared to Species 1 and Species 2.
D. R. colwelli is found significantly more frequently on Species 3 and Species 4 compared to Species 1 and Species 2.
✩CORRECT ANSWER FOR 8.5, 2✩
C
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. 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 populations have significantly decreased in size between 1996 and 2011 ?
A. White-tailed deer only
B. Cotton rats and rabbits only
C. White-tailed deer and raccoons only
D. White-tailed deer, raccoons, and cotton rats
✩CORRECT ANSWER FOR 8.5, 3✩
C
Researchers were studying species diversity in a savanna rangeland community in southwest Queensland, Australia. Researchers counted the numbers of plants species in four different categories at two nearby sites within the savanna rangeland; one lightly grazed by herbivores and one heavily grazed by herbivores (Figure 1). Which of the following best predicts the results of a drought in the savanna research area with regards to community resilience to this environmental change?
A. The heavily grazed area is more likely to recover more quickly from the drought due to reduced competition between species.
B. The lightly grazed area is likely to recover more quickly from the drought due to greater biodiversity.
C. The lightly and heavily grazed areas are likely to recover at equal rates due to the overlapping categories of plant species.
D. The lightly and heavily grazed areas are likely to recover at equal rates due to the similar climates and locations.
✩CORRECT ANSWER FOR 8.6, 1✩
B
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. 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?
A. Python parasitism has reduced the population of white-tailed deer and raccoons.
B. Python predation has caused a trophic cascade that changed the mosquitoes’ niche.
C. Pythons have a mutual symbiosis with cotton rats, allowing their population to increase.
D. Intraspecific competition for food between white-tailed deer and raccoons has increased due to pythons
✩CORRECT ANSWER FOR 8.6, 2✩
B
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. 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. Based on the data, which of the following most accurately matches a potential change with its predicted effects on the southern Florida ecosystem?
A. Introduction of a new top predator species that preys solely on Burmese pythons would cause an increase in the raccoon population.
B. If the population of Burmese pythons were to decrease, then the cotton rat population would increase.
C. If more Burmese pythons are introduced in the Everglades, then mosquitoes will begin feeding on white-tailed deer frequently again.
D. Introduction of a new snake species that competes with the Burmese python for food would lead to an increase in the white-tailed deer population.
