ACT Science : How to find research summary in biology

Study concepts, example questions & explanations for ACT Science

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Example Questions

Example Question #237 : Act Science

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 

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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?

Possible Answers:

An incorrect antibiotic will be prescribed for the patient, but it will be effective in helping the patient recover.

The patient's disease will be correctly treated.

It is impossible to predict how this mix-up will affect the patient's treatment.

An incorrect antibiotic will be prescribed for the patient and it will not be effective in helping the patient recover.

Correct answer:

An incorrect antibiotic will be prescribed for the patient and it will not be effective in helping the patient recover.

Explanation:

This question asks us to understand the general principle behind staining and classifying bacteria that is presented in the passage. The initial paragraph tells us that the Gram staining procedure and growth on selective medium is to figure out what type of bacteria is causing the disease. This is important to determine the correct antibiotic treatment, as mentioned by the passage. If a gram positive organism is accidently classified as gram negative, the wrong antibiotic will be given and a patient will not improve.

Example Question #238 : Act Science

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.)

 

Ticks

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

Possible Answers:

Biotic

Arboreal

Abiotic

Terrestrial

Correct answer:

Biotic

Explanation:

The living factors in a species' environment are known as biotic factors. The word "biotic" is derived from the Greek word "bios," which means life. This information is explicitly described in the first paragraph of the passage.

Example Question #239 : Act Science

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.)

 

Ticks

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

Possible Answers:

Population dynamics

Dynamic equilibrium

None of the other answer choices is correct.

Ecology

Correct answer:

Population dynamics

Explanation:

The first paragraph of the passage defines population dynamics as "the intricate relationships and mechanics of a given ecological community."

Example Question #240 : Act Science

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.)

 

Ticks

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

Possible Answers:

The canine parvovirus, which is abiotic because it is nonliving.

Temperature, which is an abiotic factor because it is nonliving.

Temperature, which is a biotic factor because it is living.

The canine parvovirus, which is biotic because it is a living organism.

Correct answer:

The canine parvovirus, which is abiotic because it is nonliving.

Explanation:

The passage stated that the canine parvovirus reduced the wolf population. The choices that stated that temperature was the factor that reduced the population can be ignored. The other two choices identify the parvovirus as the culprit for the reduction in the wolf population. At this point, it is necessary to determine if a virus is living or nonliving. A virus is nonliving because it cannot grow and needs a host cell or DNA donor to reproduce. The ability to reproduce is a requirement of a living organism.

Example Question #241 : Act Science

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.)

 

Ticks

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

Possible Answers:

Predation

Competition

Parasites and disease

All of the choices are density-dependent factors.

Correct answer:

All of the choices are density-dependent factors.

Explanation:

All of the choices are density-dependent factors. Competition, predation, and parasites/disease are all factors that are dependent upon population size and number. Species with fewer numbers compete for limiting resources less, are harder for predators to find, and are not easily killed off by disease/parasites due to limited interaction between population members. These factors can regulate a population when it reaches a certain level and do not greatly implicate small or scattered groups.

Example Question #242 : Act Science

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.)

 

Ticks

Which of the following choices are density-independent factors?

Possible Answers:

All of the choices are density-independent factors.

Seasonal cycles

Natural disasters

Unusual weather

Correct answer:

All of the choices are density-independent factors.

Explanation:

All of the choices are density-independent factors. Unusual weather, natural disasters, and seasonal cycles can affect a population of any size. A winter cold snap can reduce a population of any size. There is no advantage gained by having smaller or greater numbers when a population is affected by a natural disaster. These factors do do not discriminate based on population numbers and can alter groups dramatically, regardless of size.

Example Question #241 : Biology

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.)

 

Ticks

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

Possible Answers:

Rising temperatures induced weight loss and decreased fitness in the moose populations.

Rising temperatures caused both weight loss in moose populations and an increase in tick numbers.

Rising temperatures caused tick populations to grow exponentially.

Rising temperatures did not cause weight loss in the moose population nor did it result in greater tick populations.

Correct answer:

Rising temperatures caused both weight loss in moose populations and an increase in tick numbers.

Explanation:

The passage states the following: "Environmental temperatures rose dramatically in the area. Increased environmental temperatures resulted in reduced fitness and health within the moose populations of the island. Individuals were exposed to rising tick populations that cause blood loss and spread disease. Likewise, increased temperatures induce weight loss in the populations. Moose cannot perspire and must cool themselves by resting in the shade. This detracts from their ability to forage and gain weight and insulation for the colder winter months." This evidence reveals that rising temperatures induced weight loss in moose and increased tick populations. Both had detrimental effects upon the moose population.

Example Question #244 : Act Science

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.)

 

Ticks

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

Possible Answers:

Temperature fluctuations

Predation by wolves

Ticks

All of the choices are abiotic factors that led to the population's decline.

Correct answer:

Temperature fluctuations

Explanation:

According to the second paragraph of the passage, the moose populations were adversely affected by a singular abiotic factor: rising temperatures. The increased temperatures reduced the fitness and survivorship of individuals. Ticks and predation by wolves are biotic factors that led to the moose population's decline.

Example Question #245 : Act Science

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.)

 

Ticks

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

Possible Answers:

Predation by wolves

Ticks

Both ticks and predation by wolves decreased the population's numbers.

Neither ticks nor predation by wolves decreased the population's numbers.

Correct answer:

Both ticks and predation by wolves decreased the population's numbers.

Explanation:

According to the second paragraph of the passage, the moose were weakened by unseasonably hot temperatures, ticks, and increased predation by wolves. Only the ticks and wolf predation are considered to be biotic factors because they are caused by living things within the environment.

Example Question #246 : Act Science

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.)

 

Ticks

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

Possible Answers:

Density-independent factors 

Population distribution

Population ecology

Density-dependent factors

Correct answer:

Density-dependent factors

Explanation:

The passage states that "density-dependent factors such as predation have differing effects on populations based on the number of individuals present." Density-dependent factors depend on the number of individuals present in a population in order to have an impact on population size or population mechanics.

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