Unit 8 progress Check
Zebra mussels, Dreissena polymorpha, were introduced into the Great Lakes on shipping vessels, first appearing in Lake St. Clair in the 1980s. Since that time, they have rapidly expanded in range, as shown in Figure 1. (A) Lacking natural predators and able to outcompete native species of mussels and other freshwater species for food, zebra mussels have experienced exponential population growth and rapid expansion into new habitats. (B) Since their arrival, zebra mussels have undergone rapid adaptive radiation, producing new species in many different habitats. (C) Throughout their current range, zebra mussels coexist with native mussel species, whose populations have been unaffected by the arrival of zebra mussels. (D) Zebra mussels can crossbreed with native mussels, producing hybrids that are better adapted in the range shown in Figure 1.
(A) Lacking natural predators and able to outcompete native species of mussels and other freshwater species for food, zebra mussels have experienced exponential population growth and rapid expansion into new habitats.
Climate change can affect oceanic ecosystems and their food webs. In the East China Sea , three major climactic events were considered: the Pacific Decadal Oscillation , the East Asia winter monsoon , and the El Niño Southern Oscillation. What do the data in Figure 1 suggest about a null hypothesis that the East China Sea ecosystem is unaffected by climactic events? (A) The null hypothesis is rejected since there are statistical effects of and on surface sea temperature and copepod abundance. (B) The null hypothesis is rejected because the El Niño Southern Oscillation has a statistical impact on the abundance of copepods in the . (C) The null hypothesis is rejected because the and do not have statistical effects on the abundance of copepods and phytoplankton in the . (D) The null hypothesis is rejected because the El Niño
(A) The null hypothesis is rejected since there are statistical effects of and on surface sea temperature and copepod abundance
Bison in Yellowstone National Park have a food-limited carrying capacity that determines how their population grows. If the population grows too large, some bison will either starve or migrate to search for more food. The park is able to support a maximum population of 4,500 bison. Park conservation officials must watch the population and prevent the bison from overpopulating, since they would migrate to nearby farms, causing agricultural damage and creating hazards to drivers. The bison begin to migrate when the population reaches 4,000 because of competition for food. If the current population size of bison is 3,652 and the maximum growth rate of the population is 0.28, calculate the population size after one year and determine whether the park will need to take measures to control the population. (A) The population will be 3,845 after a year. The bison will not pose a problem until the following year, and no conservation action will need to take place. (B) The population will be 4,675 after a year. Some bison will need to be removed to prevent migration, since they will surpass the resource availability. (C) The population will be 1,023 after a year, since the growth rate is too low. Conservation efforts will need to focus on increasing the bison population. (D) The population will be 4,500 after a year. The bison cannot
(A) The population will be 3,845 after a year. The bison will not pose a problem until the following year, and no conservation action will need to take place.
Which of the following is the most likely cause of the change in mean aspen height from 1998 to 2010 ? (A) The reintroduction of wolves led to a decrease in the population of elk, allowing aspen trees to grow taller. (B) The reintroduction of wolves led to a decrease in the population of small mammals, allowing aspen trees to grow taller. (C) The reintroduction of wolves led to an increase in the number of carcasses that provided fertilizer for young aspen trees. (D) The reintroduction of wolves led to an increase in the number of carcasses, so coyotes no longer ate young aspen trees.
(A) The reintroduction of wolves led to a decrease in the population of elk, allowing aspen trees to grow taller.
Researchers were studying the effects of microbes on the growth of the yellow bedstraw plant, Galium verum. They grew yellow bedstraw plants under four treatments: in the presence of soil bacteria only, arbuscular mycorrhizal fungi only, both bacteria and fungi, or neither. After 6 months, they measured the biomass of the plants Which of the following best describes a statistical relationship indicated in Figure 1 ? (A) Yellow bedstraw plants grow significantly more in the presence of both soil bacteria and fungi (treatment 4) than in the presence of soil bacteria alone (treatment 2). (B) Yellow bedstraw plants, in the presence of fungi (treatment 3), grow significantly more if soil bacteria (treatment 4) are also present. (C) Yellow bedstraw plants grow significantly more when soil bacteria (treatment 2) are present compared to when there are no soil bacteria (treatment 1). (D) Yellow bedstraw plants grown in soil without bacteria and fungi
(A) Yellow bedstraw plants grow significantly more in the presence of both soil bacteria and fungi (treatment 4) than in the presence of soil bacteria alone (treatment 2).
Soluble reactive phosphate ( SRP) is a term used to describe the amount of phosphate available for uptake by living things. A study of river plants species and water phosphate levels was completed in Great Britain. (A) Reforestation efforts in Britain near this section of the river have caused changes in the plant community structure. (B) Increased fertilizer use near this section of the river has led to increased runoff of phosphates into the river. (C) Spiked water-milfoil adapted to lower phosphorous conditions has been observed to outcompete fennel- leaved pondweed in this section of the river. (D) Measured levels of in this section of the river have remained constant over a period of time.
(B) Increased fertilizer use near this section of the river has led to increased runoff of phosphates into the river.
Meerkats live together in groups to help raise and protect their offspring. Meerkat pups are most vulnerable when they are away from their burrow foraging for food. Adult meerkats exhibit sentinel behavior, standing upright and making alarm calls to warn other members in the group that predators are nearby. In a study of meerkat behaviors, scientists observed meerkat foraging groups and recorded the presence or absence of pups along with the frequency of adult sentinel behavior. The scientists determined that sentinel behavior increased when pups were present in the foraging group. Which of the following correctly identifies the dependent and independent variables in the described study? (A) The frequency of sentinel behavior is the independent variable, and the presence of pups is the dependent variable. (B) The presence of pups is the independent variable, and the frequency of sentinel behavior is the dependent variable. (C) The number of predators is the independent variable, and the presence of pups is the dependent variable. (D) The distance from the burrow is the independent variable, and
(B) The presence of pups is the independent variable, and the frequency of sentinel behavior is the dependent variable.
BT corn varieties are genetically modified to produce a toxin that specifically kills corn borers, a type of insect that eats and damages corn crops. Insects that are not closely related to corn borers are not affected by the toxin. Figure 1 shows the increasing production of corn varieties and the change in the use of broad-spectrum pesticides that were the primary means of killing corn borers before the invention of corn. How do the data in Figure 1 support the alternative hypothesis that increased use of corn reduces the impact of corn farming on the natural environment? (A) The increased use of corn will result in rapid mutation in corn borers. (B) The toxin in corn kills only the corn pests, leaving other insects unharmed. (C) Other insect species will replace corn borers and require additional applications of insecticides. (D) Since corn is not natural like non- corn, it will not interact with the rest of the environment.
(B) The toxin in corn kills only the corn pests, leaving other insects unharmed.
The marine iguana, Amblyrhynchus cristatus, is endemic to the Galápagos Islands and is especially vulnerable to El Niño events. These iguanas feed on red and green algae. During an El Niño climate event, surface waters and their currents in the central and eastern Pacific Ocean become significantly warmer than usual. Also during El Niño years, land masses experience increased rainfall. A researcher suggests that El Niño conditions cause a significant decrease in the size of the Galápagos marine iguana population. Which of the following would best support this alternative hypothesis? (A) Increased rainfall on land leads to increased nutrient runoff into the ocean and increased food resources for marina iguanas. (B) Warm surface water contains fewer nutrients needed by red and green algae than cooler surface waters does. (C) Warm surface water shortens the incubation time of marine iguana embryos. (D) Cool surface water decreases the metabolic rate of marine iguanas, so they need more food to compensate for the lowered metabolic rate.
(B) Warm surface water contains fewer nutrients needed by red and green algae than cooler surface waters does.
Which of the following best describes the change in coyote behavior in the presence of wolves? A- Rest Travel Hunt Feeding on Carcasses Vigilance Increases No effect No effect Decreases Decreases (B) Rest Travel Hunt Feeding on Carcasses Vigilance Increases Decreases No effect Decreases Decreases (C) Rest Travel Hunt Feeding on Carcasses Vigilance Decreases No effect No effect Increases Increases (D) Rest Travel Hunt Feeding on Carcasses Vigilance Decreases Increases No effect Increases Increases
(C) Rest Travel Hunt Feeding on Carcasses Vigilance Decreases No effect No effect Increases Increases
Students in a class were divided into five groups to analyze community structure. Each group of students assessed the species of plants in four environments and determined the Simpson's Diversity Index for each environment. The Simpson's Diversity Index takes into account the number of species present as well as the abundance of each species. The index values are shown in Figure 1. Based on the data in Figure 1, which of the following statements is most accurate about the species diversity of the four different environments that the students analyzed? (A) The light, moist environment is the most ideal environment for plants. (B) The most diverse environment is the dark, dry environment because plants are best able to protect themselves from drying out during the summer months. (C) Based on the data, there is no statistical difference between the species diversity of plants in the light, moist environment and in the dark, moist environment. (D) Based on the data, there is no statistical difference between the species diversity of plants in light, dry and dark, dry environments.
(C) Based on the data, there is no statistical difference between
A study recorded changes in the distribution of some commercial marine species off the East Coast of the United States over a period of several decades. The results of the study are summarized in Figure 1.Some researchers link changes in the distribution of these species to warming of the oceans due to climate change. Which of the following pieces of data best supports this alternative hypothesis? (A) Decreased acidity of ocean water in the more southern latitudes caused a migration of these species northward. (B) These species evolved new adaptations over time, allowing them to survive in warmer ocean environments. (C) The prey of these species require colder waters to survive, and owing to warming in the oceans, they are moving farther north, to higher latitudes, where the water is colder. (D) Diseases devastated the prey of these
(C) The prey of these species require colder waters to survive, and owing to warming in the oceans, they are moving farther north, to higher latitudes, where the water is colder.
Figure 1 shows the population fluctuations of phytoplankton and zooplankton in the eastern Pacific Ocean over the course of six years. The major dip in phytoplankton was attributed to a lack of nutrients for phytoplankton. Of the following, which explains why the zooplankton also dipped during the same year and then seemed to cycle over the next three years? (A) The zooplankton rely on the same nutrients for energy harvesting as the phytoplankton, so their population was also unable to acquire the necessary energy to maintain their population level. After that major dip there were enough nutrients for both categories of plankton. (B) Zooplankton are more temperature-sensitive than the phytoplankton, so the annual seasonal changes will affect their population sizes in a cyclical fashion. There was a sudden, extreme temperature change in the first dip that also affected the phytoplankton. (C) A migration of whales was blown off course by a storm one year and ate most of the phytoplankton and zooplankton. In the following years the whales returned to their normal migration route. (D) The reduction in the phytoplankton population meant that the zooplankton's energy source was drastically reduced, leading to the decrease in the zooplankton population size. After the dip, the phytoplankton provided a steady energy source, and the zooplankton population fluctuated around its carrying capacity.
(D) The reduction in the phytoplankton population meant that the zooplankton's energy source was drastically reduced, leading to the decrease in the zooplankton population size. After the dip, the phytoplankton provided a steady energy source, and the zooplankton population fluctuated around its carrying capacity.
Based on these data, an acre of land would support: • 10 humans per year on a diet of soy, or • 0.9 human per year on a diet of beef. Which of the following statements best explains these relationships in terms of energy transfer? (A) Humans are better adapted to make efficient use of soy protein than beef protein, so they can extract more energy from a gram of soy protein than from a gram of beef protein. (B) A cow can harvest energy only at a certain rate, so adding another cow to the acre of land would double the number of humans supported by the acre. (C) Preparing meat for human consumption takes more energy per gram of protein than preparing soy for consumption. (D) Only 10% of the energy on each level of the trophic pyramid
(D) Only 10% of the energy on each level of the trophic pyramid is available for use by the next level. The rest is lost as heat or used for growth and repair.
A biologist was investigating the effects of herbivory on the amount of nicotine produced by the leaves of tobacco plants (Nicotiana rustica). Six groups of plants were grown from seed in the same greenhouse with identical environmental conditions. Three groups were then each exposed for a different interval of time to tobacco hornworms (Maduca sexta), which feed on the foliage of tobacco plants. The amount of nicotine present in the leaves was measured at the beginning and end of each time interval. As a control, the other three groups were not exposed to hornworms. The results of the experiment are summarized in Table Which of the following correctly identifies the dependent variable and the independent variable for the experiment? (A) The dependent variable is the time interval the plants were exposed to the hornworms and the independent variable is the percent change in the amount of nicotine. (B) The dependent variable is the absence or presence of hornworms, and the independent variable is the initial amount of nicotine. (C) The dependent variable is the initial amount of nicotine, and the independent variable is the final amount of nicotine. (D) The dependent variable is the percent change in the amount of nicotine, and the independent variable is the time interval the plants were exposed to the hornworms.
(D) The dependent variable is the percent change in the amount of nicotine, and the independent variable is the time interval the plants were exposed to the hornworms
Baker's yeast, Saccharomycetes cerevisiae, is the species of yeast that is commonly used in baking, brewing, and making wine. It is a single-celled organism; each cell is capable of undergoing asexual reproduction by mitosis and sexual reproduction by meiosis, forming spores that combine with other spores. Which of the following best explains the data in Table 1 ? (A) All forty colonies are genetically identical. Differences in stress responses are due to experimental error. (B) Asexual reproduction allows stressed colonies to divide rapidly and compete for limited resources with other colonies. (C) Mild nutritional stress does not trigger a change in reproductive strategy among yeast cultures. (D) Yeast respond to nutritional stress with sexual reproduction, producing new genetic combinations, or dormancy.
(D) Yeast respond to nutritional stress with sexual reproduction, producing new genetic combinations, or dormancy.
Figure 1 shows a food web that describes the relationships within a community containing nine species. Each circle represents a separate species. The size of the circle represents the population size of the species relative to other species in the same trophic level. A- Big circle with lines through it on right
A- Big circle with lines through it on right
Identify the independent variable for the experimental results shown in Figure 2. A- The presence of wolves (B) The proportion of time (C) Coyote behavior (D) The study area
A- The presence of wolves
Based on the data in the figure, a student claimed that since 2007, the carrying capacity of wolves in Yellowstone National Park has been 100 wolves, and the maximum annual per capita growth rate of gray wolves is 0.6 wolves per wolf per year. Which of the following is closest to the calculated wolf population size in 2017 based on the student's claim? A- 100 B- 103 C- 113 D- 173
B- 103
Based on information in Figure 1, which of the following is closest to the annual growth rate of the wolf population in Yellowstone National Park from 1996 to 2004 ? A- 4 B- 17 C- 87 D- 135
B- 17
Sea otters question In 1991, researchers at Adak Island observed the first attack by a killer whale on a sea otter in historical times. The researchers hypothesized that the population sizes of the larger marine mammals that the killer whales normally prey on declined, so the killer whales were starting to prey on different prey, including the smaller sea otters. Which of the following best predicts the effects of an increase in killer whale predation on sea otters on the Adak Island ecosystem? (A) Both the sea urchin population and the kelp population will increase, leading to greater total biomass and diversity in the Adak Island ecosystem. (B) Both the sea urchin population and the kelp population will decrease, leading to reduced total biomass and diversity in the Adak Island ecosystem. (C) The sea urchin population will increase and the kelp population will decrease, leading to greater total biomass and diversity in the Adak Island ecosystem. (D) The sea urchin population will increase and the kelp population will decrease, leading to reduced total biomass and diversity in the Adak Island ecosystem.
D- The sea urchin population will increase and the kelp population will decrease, leading to reduced total biomass and diversity in the Adak Island ecosystem.
