Understanding the biological features of different bacteria that allow them to grow in unwelcoming environments is necessary to treat and prevent human disease. Modern scientific laboratories, such as those in major hospitals, take blood, urine, and mucus samples from patients and culture them for bacterial growth. During the culturing process, laboratory technicians stain the growing bacteria for a component of their cell wall, the structure that provides shape and rigidity to the bacterium, through a process called Gram staining. Bacteria are typically classified as Gram Positive or Gram Negative, a distinction that is important in selecting the most effective antibiotic for treatment. Gram Positive bacteria appear purple under a microscope, while Gram Negative bacteria appear red. However, some bacteria do not Gram Stain and cannot be seen under a microscope when prepared this way.

Technicians also grow the bacteria on various types of plates containing special growth nutrients to determine which bacteria are causing a specific illness. If a bacterium is able to grow on a selective plate, meaning a plate that contains additional nutrients required for a specific bacterium to grow if it is present in the culture, doctors are able to determine the exact cause of a patient’s illness and prescribe targeted antibiotics to eliminate the infection. Bacteria that commonly cause human illness, their growth requirements, and their appearance on specific growth media are presented below in Table 1.

                                                           Table 1 

Scientists can take the bacteria cultured on the plate and further analyze their enzymes. Three enzymes—urease, catalase, and beta-lactamase—are important for bacterial survival against the human immune system. Urease is responsible for producing urea, a basic molecule that can counteract the bactericidal (bacteria-killing) activity of stomach acid. Catalase, on the other hand, helps bacteria neutralize toxic substances released from human immune cells, allowing them to survive oxidative stress in high-oxygen areas. Finally, beta-lactamase allows Gram Positive bacteria to break down antibiotics called penicillins. While this ability to break down penicillin and its related antibiotic ampicillin was not initially present, bacteria, especially E. coli, have adapted by developing the new enzyme beta-lactamase that opens the ring responsible for penicillin’s bactericidal activity, rending the antibiotic ineffective. This and other examples of antibiotic resistance are becoming more common and are making treatment of serious human diseases very challenging.

A novice technician reverses the two materials needed to complete a Gram stain. Which of the following effects will this likely have on a patient’s treatment?

Population dynamics can be described as the intricate relationships and mechanics of a given ecological community. Ecology attempts to study the interactions between organisms and between organisms and their environments. Populations of organisms may be impacted by abiotic (nonliving) and biotic (living) factors within their environment. These factors may or may not depend on population densities. Density-independent factors such as weather patterns can affect a population of any size. Conversely, density-dependent factors such as predation have differing effects on populations based on the number of individuals present.

Utilizing this information, consider the following scenario.

An island contains several wolf and moose populations. Ecologists studied these populations through several generations and made observations on each population's size and relative fitness. In the initial years of the investigation, wolf populations declined due to a disease known as canine parvovirus. Due to decreased predatory pressures, the moose population rose to higher numbers than seen in previous years. Several years later, environmental temperatures rose dramatically in the area. Increased environmental temperatures resulted in reduced fitness and health within the island's moose population. Individuals were exposed to rising tick populations that caused blood loss and spread disease. Likewise, increased temperatures induced weight loss in the moose population; moose cannot perspire and must cool themselves by resting in the shade, and this detracts from their ability to forage and gain weight and insulation for the colder winter months. The weakened moose population became susceptible to increased predation by wolves, which resulted in an increase in the wolf population. (See Figures 1, 2, and 3.)

Which of the following choices describe the living factors present in a species' environment?

Population dynamics can be described as the intricate relationships and mechanics of a given ecological community. Ecology attempts to study the interactions between organisms and between organisms and their environments. Populations of organisms may be impacted by abiotic (nonliving) and biotic (living) factors within their environment. These factors may or may not depend on population densities. Density-independent factors such as weather patterns can affect a population of any size. Conversely, density-dependent factors such as predation have differing effects on populations based on the number of individuals present.

Utilizing this information, consider the following scenario.

An island contains several wolf and moose populations. Ecologists studied these populations through several generations and made observations on each population's size and relative fitness. In the initial years of the investigation, wolf populations declined due to a disease known as canine parvovirus. Due to decreased predatory pressures, the moose population rose to higher numbers than seen in previous years. Several years later, environmental temperatures rose dramatically in the area. Increased environmental temperatures resulted in reduced fitness and health within the island's moose population. Individuals were exposed to rising tick populations that caused blood loss and spread disease. Likewise, increased temperatures induced weight loss in the moose population; moose cannot perspire and must cool themselves by resting in the shade, and this detracts from their ability to forage and gain weight and insulation for the colder winter months. The weakened moose population became susceptible to increased predation by wolves, which resulted in an increase in the wolf population. (See Figures 1, 2, and 3.)

Which of the following choices can be defined as the complex inner workings of a given ecological community?

Population dynamics can be described as the intricate relationships and mechanics of a given ecological community. Ecology attempts to study the interactions between organisms and between organisms and their environments. Populations of organisms may be impacted by abiotic (nonliving) and biotic (living) factors within their environment. These factors may or may not depend on population densities. Density-independent factors such as weather patterns can affect a population of any size. Conversely, density-dependent factors such as predation have differing effects on populations based on the number of individuals present.

Utilizing this information, consider the following scenario.

An island contains several wolf and moose populations. Ecologists studied these populations through several generations and made observations on each population's size and relative fitness. In the initial years of the investigation, wolf populations declined due to a disease known as canine parvovirus. Due to decreased predatory pressures, the moose population rose to higher numbers than seen in previous years. Several years later, environmental temperatures rose dramatically in the area. Increased environmental temperatures resulted in reduced fitness and health within the island's moose population. Individuals were exposed to rising tick populations that caused blood loss and spread disease. Likewise, increased temperatures induced weight loss in the moose population; moose cannot perspire and must cool themselves by resting in the shade, and this detracts from their ability to forage and gain weight and insulation for the colder winter months. The weakened moose population became susceptible to increased predation by wolves, which resulted in an increase in the wolf population. (See Figures 1, 2, and 3.)

Was the factor that reduced the wolf population caused by a biotic or abiotic component of the environment?

Population dynamics can be described as the intricate relationships and mechanics of a given ecological community. Ecology attempts to study the interactions between organisms and between organisms and their environments. Populations of organisms may be impacted by abiotic (nonliving) and biotic (living) factors within their environment. These factors may or may not depend on population densities. Density-independent factors such as weather patterns can affect a population of any size. Conversely, density-dependent factors such as predation have differing effects on populations based on the number of individuals present.

Utilizing this information, consider the following scenario.

An island contains several wolf and moose populations. Ecologists studied these populations through several generations and made observations on each population's size and relative fitness. In the initial years of the investigation, wolf populations declined due to a disease known as canine parvovirus. Due to decreased predatory pressures, the moose population rose to higher numbers than seen in previous years. Several years later, environmental temperatures rose dramatically in the area. Increased environmental temperatures resulted in reduced fitness and health within the island's moose population. Individuals were exposed to rising tick populations that caused blood loss and spread disease. Likewise, increased temperatures induced weight loss in the moose population; moose cannot perspire and must cool themselves by resting in the shade, and this detracts from their ability to forage and gain weight and insulation for the colder winter months. The weakened moose population became susceptible to increased predation by wolves, which resulted in an increase in the wolf population. (See Figures 1, 2, and 3.)

Which of the following choices can be considered density-dependent factors?

Population dynamics can be described as the intricate relationships and mechanics of a given ecological community. Ecology attempts to study the interactions between organisms and between organisms and their environments. Populations of organisms may be impacted by abiotic (nonliving) and biotic (living) factors within their environment. These factors may or may not depend on population densities. Density-independent factors such as weather patterns can affect a population of any size. Conversely, density-dependent factors such as predation have differing effects on populations based on the number of individuals present.

Utilizing this information, consider the following scenario.

An island contains several wolf and moose populations. Ecologists studied these populations through several generations and made observations on each population's size and relative fitness. In the initial years of the investigation, wolf populations declined due to a disease known as canine parvovirus. Due to decreased predatory pressures, the moose population rose to higher numbers than seen in previous years. Several years later, environmental temperatures rose dramatically in the area. Increased environmental temperatures resulted in reduced fitness and health within the island's moose population. Individuals were exposed to rising tick populations that caused blood loss and spread disease. Likewise, increased temperatures induced weight loss in the moose population; moose cannot perspire and must cool themselves by resting in the shade, and this detracts from their ability to forage and gain weight and insulation for the colder winter months. The weakened moose population became susceptible to increased predation by wolves, which resulted in an increase in the wolf population. (See Figures 1, 2, and 3.)

Which of the following choices are density-independent factors?

Population dynamics can be described as the intricate relationships and mechanics of a given ecological community. Ecology attempts to study the interactions between organisms and between organisms and their environments. Populations of organisms may be impacted by abiotic (nonliving) and biotic (living) factors within their environment. These factors may or may not depend on population densities. Density-independent factors such as weather patterns can affect a population of any size. Conversely, density-dependent factors such as predation have differing effects on populations based on the number of individuals present.

Utilizing this information, consider the following scenario.

An island contains several wolf and moose populations. Ecologists studied these populations through several generations and made observations on each population's size and relative fitness. In the initial years of the investigation, wolf populations declined due to a disease known as canine parvovirus. Due to decreased predatory pressures, the moose population rose to higher numbers than seen in previous years. Several years later, environmental temperatures rose dramatically in the area. Increased environmental temperatures resulted in reduced fitness and health within the island's moose population. Individuals were exposed to rising tick populations that caused blood loss and spread disease. Likewise, increased temperatures induced weight loss in the moose population; moose cannot perspire and must cool themselves by resting in the shade, and this detracts from their ability to forage and gain weight and insulation for the colder winter months. The weakened moose population became susceptible to increased predation by wolves, which resulted in an increase in the wolf population. (See Figures 1, 2, and 3.)

How did rising temperatures impact the populations on the hypothetical island under study?

Population dynamics can be described as the intricate relationships and mechanics of a given ecological community. Ecology attempts to study the interactions between organisms and between organisms and their environments. Populations of organisms may be impacted by abiotic (nonliving) and biotic (living) factors within their environment. These factors may or may not depend on population densities. Density-independent factors such as weather patterns can affect a population of any size. Conversely, density-dependent factors such as predation have differing effects on populations based on the number of individuals present.

Utilizing this information, consider the following scenario.

An island contains several wolf and moose populations. Ecologists studied these populations through several generations and made observations on each population's size and relative fitness. In the initial years of the investigation, wolf populations declined due to a disease known as canine parvovirus. Due to decreased predatory pressures, the moose population rose to higher numbers than seen in previous years. Several years later, environmental temperatures rose dramatically in the area. Increased environmental temperatures resulted in reduced fitness and health within the island's moose population. Individuals were exposed to rising tick populations that caused blood loss and spread disease. Likewise, increased temperatures induced weight loss in the moose population; moose cannot perspire and must cool themselves by resting in the shade, and this detracts from their ability to forage and gain weight and insulation for the colder winter months. The weakened moose population became susceptible to increased predation by wolves, which resulted in an increase in the wolf population. (See Figures 1, 2, and 3.)

According to the passage, which abiotic factors led to the moose population's decline?

Population dynamics can be described as the intricate relationships and mechanics of a given ecological community. Ecology attempts to study the interactions between organisms and between organisms and their environments. Populations of organisms may be impacted by abiotic (nonliving) and biotic (living) factors within their environment. These factors may or may not depend on population densities. Density-independent factors such as weather patterns can affect a population of any size. Conversely, density-dependent factors such as predation have differing effects on populations based on the number of individuals present.

Utilizing this information, consider the following scenario.

An island contains several wolf and moose populations. Ecologists studied these populations through several generations and made observations on each population's size and relative fitness. In the initial years of the investigation, wolf populations declined due to a disease known as canine parvovirus. Due to decreased predatory pressures, the moose population rose to higher numbers than seen in previous years. Several years later, environmental temperatures rose dramatically in the area. Increased environmental temperatures resulted in reduced fitness and health within the island's moose population. Individuals were exposed to rising tick populations that caused blood loss and spread disease. Likewise, increased temperatures induced weight loss in the moose population; moose cannot perspire and must cool themselves by resting in the shade, and this detracts from their ability to forage and gain weight and insulation for the colder winter months. The weakened moose population became susceptible to increased predation by wolves, which resulted in an increase in the wolf population. (See Figures 1, 2, and 3.)

According to the passage, which of the following biotic factors caused the moose population to decline?

Population dynamics can be described as the intricate relationships and mechanics of a given ecological community. Ecology attempts to study the interactions between organisms and between organisms and their environments. Populations of organisms may be impacted by abiotic (nonliving) and biotic (living) factors within their environment. These factors may or may not depend on population densities. Density-independent factors such as weather patterns can affect a population of any size. Conversely, density-dependent factors such as predation have differing effects on populations based on the number of individuals present.

Utilizing this information, consider the following scenario.

An island contains several wolf and moose populations. Ecologists studied these populations through several generations and made observations on each population's size and relative fitness. In the initial years of the investigation, wolf populations declined due to a disease known as canine parvovirus. Due to decreased predatory pressures, the moose population rose to higher numbers than seen in previous years. Several years later, environmental temperatures rose dramatically in the area. Increased environmental temperatures resulted in reduced fitness and health within the island's moose population. Individuals were exposed to rising tick populations that caused blood loss and spread disease. Likewise, increased temperatures induced weight loss in the moose population; moose cannot perspire and must cool themselves by resting in the shade, and this detracts from their ability to forage and gain weight and insulation for the colder winter months. The weakened moose population became susceptible to increased predation by wolves, which resulted in an increase in the wolf population. (See Figures 1, 2, and 3.)

Which of the following choices can be defined as factors that alter a population based upon size and numbers of individuals present?