AP Bio Unit 8 Practice questions

A population of 250 birds inhabit the 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?

0.35

Assume a linear food chain contains 1,000 kg of primary producer biomass. How many kilograms of biomass can be supported at the level of the secondary consumer?

10 kg

A population of grey reef sharks in a coral reef has a maximum per capita growth rate of 1.5 per year. The population size is limited by the carrying capacity of the reef, which is 50 individuals. Which of the following is the growth rate of the shark population when the population is made up of 30 individuals?

18 sharks

A city identifies that it has a problem with Norwegian rats (Rattus norvegicus). A population ecologist is hired to study the situation. She determines that the current population of rats in the city is 4,000 individuals and has an annual birth rate of 0.03. A city-wide trapping program has increased the annual death rate to 0.01. Given this information, the population ecologist reports that in one year, the rat population will be

4080 individuals

A fish population of 250 in a pond has a maximum annual rate of increase of 0.8. If the carrying capacity of the pond is 1,500 for this species, what is the expected population size after one year?

417

Which of the following is/are (a) key part(s) of the carbon cycle?

All of the listed responses are correct

Which of the following is an example of a density-independent limitation on a population?

At higher temperatures, more tomato plants in a population become infested with nematodes than at lower temperatures.

Put the ecological regions in order from most diverse to least diverse

Biosphere Biome Ecosystem/Habitat Community Population

In an experiment to determine the effect of light availability on species richness in an environment, a grassland was divided into 26 plots that were assigned to one of two treatment groups: 1. Clipped - plots were mowed to simulate the grazing of herbivores that maintain the low height of grasses. 2. Enclosure - plots were enclosed in fences, and grasses were allowed to grow undisturbed to their maximum height. After eight years, data was collected on the amount of light penetration to the soil (bottom light density) and the number of species in the two treatment groups. Figure 1 shows the averaged light penetration measurements, and Figure 2 shows the averaged number of species per plot type. Which of the following statements is consistent with the data shown in the figures?

Different patterns of energy availability in ecosystems will affect species richness.

Which point on the curve in the diagram above best represents the carrying capacity of the environment for the population shown?

E

The rate of increase in the biomass of a heterotroph depends on the metabolic needs of the organism. Which of the following types of organisms would be a more efficient secondary consumer and why?

Ectotherm because it spends less energy maintaining body temperature.

What determines the size of a food chain or food web?

Every level is regulated by the amount of producers at the bottom

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.

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.

One model of a sustainable fisheries practice is for individual fish to be removed from a natural population at a rate equal to the highest possible growth rate of an ideal population. The graph above represents a population of bluefin tuna living along the Atlantic coast. At which labeled point in the graph is the population growth rate the highest?

III

Which of the following changes to the environment will most likely lead to more energy entering the meadow community represented below?

Increasing the light available to the plants

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. Based on the data, which of the following most accurately matches a potential change with its predicted effects on the southern Florida ecosystem?

Introduction of a new top predator species that preys solely on Burmese pythons would cause an increase in the raccoon population.

The biggest difference between the flow of energy and the flow of chemical nutrients in an ecosystem is that

nutrients are recycled, but energy is not

Which of the following is true of the nitrogen cycle?

Nitrite is converted to nitrate (NO3-) by nitrifying bacteria.

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. Which of the following most accurately explains an impact of Burmese pythons on the Everglades community in southern Florida using the data provided?

Python predation has caused a trophic cascade that changed the mosquitoes' niche

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 ?

R. richardsoni is found significantly more frequently on Species 3 and Species 4 compared to Species 1 and Species 2.

Scientists measured the electromagnetic (EM) radiation reflected or emitted by more that 2,100 eggs laid by 251 different kinds of birds. This research suggests that some aspect of EM spectrum might be an important factor used by birds to identify a given egg. Which of the following is the LEAST appropriate test to determine the validity of this claim?

Remove a cuckoo egg from its nest at 8 A.M., and return it to the same nest four hours later.

In an experiment, three different animals were exposed to a series of environmental temperatures and their body temperatures were assessed at multiple temperature points between 10 and 40 degrees Celsius. Ten different individuals of each type of animal were included in the study to produce an average body temperature profile for each type of animal. Figure 1 shows the data collected Which of the following statements is most consistent with the data in Figure 1 ?

Snakes display behaviors that allow them to absorb or radiate heat as required.

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. Scientists hypothesize that the invasive Burmese pythons are responsible for recent increases in human Everglades virus infections. Evaluate this alternate hypothesis using the data provided.

The alternate hypothesis is supported because the invasive Burmese pythons caused mosquitoes to switch to feeding on cotton rats. This means that mosquitoes are more likely to carry the Everglades virus when they bite humans.

The deep ocean floor communities contain very little life. In constant darkness, the water at these depths hovers around 2°C. Sparsely distributed in this environment are hydrothermal vent ecosystems. Superheated water streams out of the vents at temperatures approaching 400°C. These waters are rich in inorganic materials, including carbon dioxide and hydrogen sulfide. Hydrothermal vent zones have a density of organisms 10,000 to 100,000 times greater than found on the surrounding seafloor. Scientists have studied these vents to determine the energy source for these communities and the identity of the primary producers in the perpetual darkness of the ocean floor. As expected, they found a total absence of photosynthetic organisms at all vents, identifying mats of bacteria as the producers of the carbon compounds that are used by the rest of the community for growth, repair, and as an energy source. Which of the following describes how the vent bacteria harvest energy to produce organic compounds for use by the vent community?

The bacteria function as chemoautotrophs, extracting energy from hydrogen-rich inorganic molecules.

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?

The independent variable is the type of alarm, and the dependent variable is the percent of squirrels responding.

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?

The lightly grazed area is likely to recover more quickly from the drought due to greater biodiversity.

Only a small portion of chemical energy in an apple is transferred to an organism that eats it. Which of the following occurs to the majority of the chemical energy stored in the apple when another organism eats it?

The majority of the energy is lost as heat energy to the surrounding environment.

Students investigated the effect of light on the carbon cycle in aquatic ecosystems by performing the controlled experiment summarized below. The students placed equal amounts of water (pH 7.0) from a large aquarium in glass beakers. The students transferred aquatic plants from the aquarium to several of the beakers, and then they placed equal numbers of the beakers in the light or the dark (Figure 1: groups I and II). Similarly, the students transferred goldfish from the same aquarium to other beakers, and then they placed equal numbers of those beakers in the light or dark (Figure 1: groups III and IV). Finally, the students placed an equal number of beakers containing water only in the light or dark (Figure 1: groups V and VI). After exposing the samples to the light or dark for one hour, the students recorded the pH of the water in each beaker. Carbon dioxide dissolved in water will lower the pH of an aqueous solution. In the experiment, the students used changes in pH to monitor changes in the amount of carbon dioxide in the water. For each treatment group, the students calculated the meant pH and standard error, as documented in the table below. Which of the following observations provides the best evidence that photosynthesis occurred in treatment group I?

The mean pH of the samples increased after one hour

Potatoes as a food crop originated in South America. There are over 4,000 variations of potato grown there. Potatoes were brought to Europe by Spanish colonists in the late 1500s. One variety became the chief crop grown in much of Ireland by the early 1800s. Table 1 summarizes the spread of potatoes as a food crop. A researcher suggests that the Irish monoculture (growing a single crop) of the Lumper potato did not significantly change the overall resistance of the potato crop in Ireland to diseases. Which of the following observations best refutes this null hypothesis?

The number of fatalities from the Irish potato famine was greater than the rest of the European countries combined.

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?

The percentage of plants showing phototropism is the dependent variable, and the color of the light is the independent variable.

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 this 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.

The population would grow to 63,667 deer in a year, and the growth rate would decrease the following year.

Zebra mussels are an invasive species that has become widely established throughout the United States. Figure 1 shows the percent change in the population sizes of selected groups of organisms in the Hudson River since the introduction of zebra mussels. In this study chlorophyll-containing bacteria are considered phytoplankton and all other bacteria are considered bacterioplankton. Which of the following hypotheses about the effect of zebra mussels on the Hudson River community is best supported by the data in Figure 1 ?

The reduction in primary productivity has resulted in an unstable community that will eventually collapse.

Figure 1 shows the changing pattern of human population sizes in rural and urban areas from 1960 to 2016 with regard to the global population. A scientist interested in investigating how human population trends might affect local animal species' richness stipulates a null hypothesis that animal biodiversity in rural areas will be unaffected in the future by the human population trends shown in Figure 1. Which of the following would best refute this null hypothesis?

Urbanization causes habitat fragmentation

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. Which of the following populations have significantly decreased in size between 1996 and 2011 ?

White-tailed deer and raccoons only

Different species of bumblebee compete for flower nectar in their ecosystem. While the flowers vary in the length of their petals, bumblebees vary in the length of a mouth part called a proboscis. Bumblebees demonstrate a preference for flowers that correspond to the length of their proboscis. Species with proboscises of similar length tend to occupy different areas. Species that live in the same area tend to have proboscises of different lengths. Which of the following best explains the relationship between the different bumblebee species living in the same area?

With no natural predators, the lionfish population will become very large.

Pine trees in a forest tend to shade and kill pine seedlings that sprout nearby. This causes the pine trees to

a relatively flat line that drops steeply at the end

When the predators were removed, the variety of species ________________

decreased

The graph below shows changes in a population of wild sheep that were introduced to the island of Tasmania in the early 1800's. The type of population growth represented by that portion of the graph line enclosed in the bracket is most accurately termed

exponential

Scientists studying a wild population of mantled howler monkeys found the average birth rate to be 0.22 and the average death rate to be 0.12. At the start of the study, the population consisted of 13 monkeys. Assuming no immigration or emigration, which of the following best describes the change in population size that will occur over the next year?

he population will increase because more monkeys are being born each year than are dying.

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?

intermittent streams only

"Plants are green" because _______________________

predators keep herbivores in check

The energy suppliers in a food chain

producers

________________ are another keystone species.

sea otters

An increase in the number of orcas caused an increase in the number of ___________________

sea urchins

In the tide pool food chain, the ____________________ were the keystone species.

starfish

Fur color is a genetically controlled trait in mice. A population of a species of mouse that typically lives in habitats with light-colored soil was studied for several generations. The background color of the habitat of this population became darker after the second generation due to human activity. A researcher sampled approximately 120 mice in each generation and recorded the fur color phenotypes as shown in Figure 1 The researcher claims that there is no selective advantage to fur color, so light and dark fur color phenotypes are present in similar frequencies in the fourth generation of this mouse population. Based on the data in Figure 1, which of the following best evaluates this null hypothesis?

the null hypothesis is rejected, because the change to a darker background color led to an increase in the dark-colored fur phenotype.

When otters were absent

the population of sea kelp decreased

The graph below illustrates a logistic growth curve for a population of Euglena.

the reproductive rate equals the death rate

The effect of one species "downward" on others

trophic cascade

In many developing countries with poor nutrition, limited access to medical treatment, and a lack of access to clean water, infant mortality rates are very high. However, as children ge older their likelihood of surviving increases. In such populations, the death rate decreases as the population ages. Which of the following types of curve(s) BEST respresents the growth patterns observed in developing countries?

type III

All of the following are density-dependent factors that limit animal populations EXCEPT

weather