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Evolutionary pressure, also termed selective pressure, encompasses any environmental factor that influences an organism's capacity for survival and reproduction.
Answer: True
Explanation: Evolutionary pressure, also known as selective pressure, refers to any factor that influences the reproductive success of individuals within a population. These pressures can either reduce or increase an organism's ability to reproduce, thereby driving the process of natural selection.
In population genetics, the selection coefficient serves as a quantitative measure for the intensity of selection acting upon a specific trait.
Answer: True
Explanation: In population genetics, selective pressure is typically quantified using a measure called the selection coefficient. This coefficient provides a numerical value representing the strength of selection acting on a particular trait or gene.
The concept of selective pressure is exclusively applied within the field of evolutionary biology.
Answer: False
Explanation: While primarily used in evolutionary biology, the concept of selective pressure is also extended to other research areas. It serves as a quantitative description for the changes occurring in various processes studied within these fields.
In biological terminology, 'fitness' refers to an organism's relative reproductive success and its capacity to adapt to its environment.
Answer: True
Explanation: In biology, fitness refers to an organism's expected reproductive success. It is a measure of how well an organism is adapted to its environment and its ability to pass on its genes to the next generation.
The phrase commonly associated with natural selection, emphasizing adaptation and reproductive success, is 'survival of the fittest'.
Answer: True
Explanation: The phrase 'survival of the fittest' is commonly used to describe the mechanism of natural selection, emphasizing that individuals best suited to their environment are most likely to survive and reproduce.
Conserved sequences, whether in DNA or proteins, are those that have remained relatively unchanged across different species or over long evolutionary periods, indicating functional importance.
Answer: True
Explanation: Conserved sequences are similar DNA, RNA, or protein sequences that are found within the genomes of different species or even within the same species. Their similarity suggests they have remained relatively unchanged over evolutionary time due to functional importance.
Adaptation is the process driven by evolutionary pressure, leading to populations better suited to their environment.
Answer: True
Explanation: Evolutionary pressure is the driving force behind adaptation. Environmental factors or challenges (selective pressures) favor individuals with certain traits, leading to the gradual accumulation of those traits in the population over generations, resulting in adaptation.
Genetic drift and selective pressure are identical mechanisms driving evolutionary change.
Answer: False
Explanation: While selective pressure drives evolution by favoring advantageous traits, genetic drift is a random process where allele frequencies change due to chance events, not necessarily due to the trait's benefit or detriment to survival or reproduction. Selective pressure is directional, whereas genetic drift is random.
Mutations are necessary for selective pressure to act upon, as they introduce the required genetic variation.
Answer: True
Explanation: Mutations introduce new genetic variations into a population. Selective pressure then acts upon this variation, favoring mutations that increase an organism's fitness and weeding out those that decrease it, thereby shaping the evolutionary path of the population.
Evolutionary pressure can originate from both natural environmental factors and human activities.
Answer: True
Explanation: Evolutionary pressure can be both natural, arising from environmental factors like climate or predation, and human-induced, resulting from activities such as pollution, habitat modification, hunting, or the introduction of chemicals like antibiotics and pesticides.
Coevolution describes a reciprocal evolutionary process where species exert selective pressures on each other, leading to adaptations in response.
Answer: True
Explanation: Coevolution occurs when two or more species reciprocally influence each other's evolution through selective pressures. For example, the evolutionary arms race between pathogenic bacteria and humans involves coevolutionary pressures, where each exerts selective pressure on the other.
Gene flow introduces genetic variation upon which selective pressure can act, and conversely, selective pressure can influence the rate and extent of gene flow.
Answer: True
Explanation: Gene flow, the movement of genes between populations, can introduce new genetic variations that selective pressure can then act upon. Conversely, strong selective pressure within a population might reduce gene flow if individuals with traits favored by selection are less likely to migrate.
What is the fundamental definition of evolutionary pressure?
Answer: Any factor influencing the reproductive success of individuals in a population.
Explanation: Evolutionary pressure, also known as selective pressure, refers to any factor that influences the reproductive success of individuals within a population. These pressures can either reduce or increase an organism's ability to reproduce, thereby driving the process of natural selection.
How is the strength of selection quantified in population genetics?
Answer: Through a measure called the selection coefficient.
Explanation: In population genetics, selective pressure is typically quantified using a measure called the selection coefficient. This coefficient provides a numerical value representing the strength of selection acting on a particular trait or gene.
What is the biological definition of 'fitness'?
Answer: An organism's expected reproductive success.
Explanation: In biology, fitness refers to an organism's expected reproductive success. It is a measure of how well an organism is adapted to its environment and its ability to pass on its genes to the next generation.
The phrase commonly used to describe natural selection, emphasizing adaptation to the environment, is:
Answer: Survival of the fittest.
Explanation: The phrase 'survival of the fittest' is commonly used to describe the mechanism of natural selection, emphasizing that individuals best suited to their environment are most likely to survive and reproduce.
What is the relationship between evolutionary pressure and adaptation?
Answer: Evolutionary pressure is the driving force behind adaptation.
Explanation: Evolutionary pressure is the driving force behind adaptation. Environmental factors or challenges (selective pressures) favor individuals with certain traits, leading to the gradual accumulation of those traits in the population over generations, resulting in adaptation.
How does genetic drift differ fundamentally from selective pressure?
Answer: Selective pressure favors beneficial traits; genetic drift involves random changes in allele frequencies.
Explanation: While selective pressure drives evolution by favoring advantageous traits, genetic drift is a random process where allele frequencies change due to chance events, not necessarily due to the trait's benefit or detriment to survival or reproduction. Selective pressure is directional, whereas genetic drift is random.
What role do mutations play concerning selective pressure?
Answer: Mutations introduce genetic variation upon which selective pressure acts.
Explanation: Mutations introduce new genetic variations into a population. Selective pressure then acts upon this variation, favoring mutations that increase an organism's fitness and weeding out those that decrease it, thereby shaping the evolutionary path of the population.
Coevolution, in the context of bacteria and humans, is best described as:
Answer: A reciprocal evolutionary process driven by selective pressures between the two.
Explanation: Coevolution occurs when two or more species reciprocally influence each other's evolution through selective pressures. For example, the evolutionary arms race between pathogenic bacteria and humans involves coevolutionary pressures, where each exerts selective pressure on the other.
What is the relationship between gene flow and selective pressure?
Answer: Selective pressure can reduce gene flow by favoring localized adaptations.
Explanation: Gene flow introduces genetic variation upon which selective pressure can act, and conversely, selective pressure can influence the rate and extent of gene flow. Strong selective pressure within a population might reduce gene flow if individuals with traits favored by selection are less likely to migrate.
What is the significance of conserved sequences in biology?
Answer: They suggest sequences that have remained relatively unchanged due to functional importance.
Explanation: Conserved sequences, whether in DNA or proteins, are those that have remained relatively unchanged across different species or over long evolutionary periods, indicating functional importance.
How does gene flow interact with selective pressure?
Answer: Selective pressure can reduce gene flow by favoring localized adaptations.
Explanation: Gene flow introduces genetic variation upon which selective pressure can act, and conversely, selective pressure can influence the rate and extent of gene flow. Strong selective pressure within a population might reduce gene flow if individuals with traits favored by selection are less likely to migrate.
What is the relationship between gene flow and selective pressure?
Answer: Selective pressure can reduce gene flow by favoring localized adaptations.
Explanation: Gene flow introduces genetic variation upon which selective pressure can act, and conversely, selective pressure can influence the rate and extent of gene flow. Strong selective pressure within a population might reduce gene flow if individuals with traits favored by selection are less likely to migrate.
In yeast, subjecting the HIS4 gene to amino acid selective pressure enhances the expression of adjacent genes.
Answer: True
Explanation: When an amino acid bio-synthesizing gene such as HIS4 is subjected to amino acid selective pressure in yeast, it has been observed to enhance the expression of adjacent genes. This phenomenon is attributed to the co-regulation of these genes at the transcriptional level in eukaryotic organisms.
The malaria parasite exerts selective pressure by favoring individuals with genetic traits that increase susceptibility to severe disease.
Answer: False
Explanation: The malaria parasite exerts selective pressure on human populations by causing disease and death. This pressure favors individuals with genetic traits that confer resistance to malaria, such as carrying the sickle cell hemoglobin gene mutation.
The Hb S mutation, causing sickle cell anemia, increases a person's susceptibility to severe malaria.
Answer: False
Explanation: The mutation in the hemoglobin gene that causes sickle cell anemia, known as the Hb S mutation, provides a degree of resistance to malaria. Individuals carrying this mutation are less likely to suffer severe consequences from malaria infection.
Decreases in salinity in the Baltic Sea have been identified as an environmental change that has encouraged the emergence of a new species of brown seaweed, *Fucus radicans*.
Answer: True
Explanation: Decreases in salinity in the Baltic Sea have been identified as an environmental change that has encouraged the emergence of a new species of brown seaweed, *Fucus radicans*.
The malaria parasite exerts selective pressure on human populations by causing disease and death, favoring individuals with genetic resistance.
Answer: True
Explanation: The malaria parasite exerts selective pressure on human populations by causing disease and death. This pressure favors individuals with genetic traits that confer resistance to malaria, such as carrying the sickle cell hemoglobin gene mutation.
The Hb S mutation provides complete immunity to malaria.
Answer: False
Explanation: The mutation in the hemoglobin gene that causes sickle cell anemia, known as the Hb S mutation, provides a degree of resistance to malaria, but not complete immunity. Individuals carrying this mutation are less likely to suffer severe consequences from malaria infection.
Which genetic trait provides humans with a degree of resistance to malaria?
Answer: The sickle cell hemoglobin gene mutation (Hb S).
Explanation: The mutation in the hemoglobin gene that causes sickle cell anemia, known as the Hb S mutation, provides a degree of resistance to malaria. Individuals carrying this mutation are less likely to suffer severe consequences from malaria infection.
What environmental factor change in the Baltic Sea has influenced the emergence of *Fucus radicans*?
Answer: Decreased salinity.
Explanation: Decreases in salinity in the Baltic Sea have been identified as an environmental change that has encouraged the emergence of a new species of brown seaweed, *Fucus radicans*.
What is the significance of the Hb S mutation in relation to malaria?
Answer: It provides a degree of resistance to malaria.
Explanation: The mutation in the hemoglobin gene that causes sickle cell anemia, known as the Hb S mutation, provides a degree of resistance to malaria. Individuals carrying this mutation are less likely to suffer severe consequences from malaria infection.
What factor has led to the emergence of a new seaweed species, *Fucus radicans*, in the Baltic Sea?
Answer: Decreased salinity.
Explanation: Decreases in salinity in the Baltic Sea have been identified as an environmental change that has encouraged the emergence of a new species of brown seaweed, *Fucus radicans*.
The phenomenon of antibiotic resistance in bacteria exemplifies natural selection, wherein bacteria lacking resistance mechanisms perish under antibiotic exposure, while resistant strains survive and propagate.
Answer: True
Explanation: Antibiotic resistance in bacteria exemplifies natural selection because when antibiotics are applied, bacteria that cannot resist the drug die and do not reproduce. Conversely, bacteria that possess resistance genes survive, reproduce, and pass these advantageous traits to subsequent generations, leading to an increase in resistance over time.
Antibiotic resistance genes can be transmitted through both vertical gene transmission (parent to offspring) and horizontal gene transmission (between bacteria).
Answer: True
Explanation: Antibiotic resistance genes can be transmitted through two main pathways: vertical gene transmission, where a resistant bacterium passes the gene to its offspring, and horizontal gene transmission, where one bacterium transfers the resistance gene to another bacterium, even of a different species.
Hospitals can foster antibiotic resistance in pathogens like *C. difficile* by exposing them to antibiotics, thereby favoring resistant strains.
Answer: True
Explanation: Hospitals create environments where pathogens such as *Clostridioides difficile* (*C. difficile*) are exposed to antibiotics, leading to the development of resistance. This selective pressure favors bacteria that can survive antibiotic treatment.
Completing the prescribed course of antibiotics is a practice that worsens antibiotic resistance.
Answer: False
Explanation: Antibiotic resistance is worsened by the misuse of antibiotics, such as not completing the prescribed course of treatment. This practice can allow partially resistant bacteria to survive and multiply.
Antibiotic resistance can emerge in bacteria solely through new, spontaneous mutations.
Answer: False
Explanation: Antibiotic resistance can emerge in a bacterial population either through pre-existing genetic variations within the population or through new mutations that arise spontaneously. Both pathways can lead to the development of resistance.
*Clostridioides difficile* is a significant concern in healthcare settings primarily due to its role as a cause of nosocomial infections, particularly severe gastrointestinal issues.
Answer: True
Explanation: *Clostridioides difficile* is a significant cause of death from nosocomial infections, which are infections acquired during a hospital stay, often leading to severe gastrointestinal issues.
Antibiotic treatment disrupts gut flora, making individuals less susceptible to opportunistic pathogens like *C. difficile*.
Answer: False
Explanation: When the natural balance of symbiotic gut flora is disturbed by antibiotic treatment, an individual becomes more susceptible to opportunistic pathogens like *C. difficile*, as the absence of beneficial bacteria allows *C. difficile* to proliferate.
The Red Queen hypothesis posits that species must continuously adapt and evolve not just to gain reproductive advantage, but also simply to survive while pitted against ever-evolving opposing species.
Answer: True
Explanation: The Red Queen hypothesis, in the context of bacteria and humans, describes an ongoing evolutionary arms race. It suggests that pathogenic bacteria are constantly evolving virulence factors to outcompete human defenses and treatments, while humans (through medicine) evolve countermeasures, creating a continuous cycle of adaptation and counter-adaptation.
Toxin TcdA produced by *C. difficile* contributes to its pathogenicity and resistance.
Answer: True
Explanation: Virulence factors are characteristics that enhance pathogenicity. For *C. difficile*, key virulence factors include toxins like enterotoxin TcdA and cytotoxin TcdB, which contribute to its ability to cause severe intestinal issues and resist antibiotic treatments.
*C. difficile* spores can remain infectious in the environment for up to 5 weeks.
Answer: False
Explanation: *C. difficile* spores can remain viable and infectious in the environment for extended periods, potentially up to 20 weeks. This persistence is particularly problematic in hospitals, where spores can contaminate surfaces and facilitate the spread of infection among patients.
Hand hygiene and glove use are recommended practices to control the spread of *C. difficile*.
Answer: True
Explanation: To control the spread of CDIs, essential sanitation practices in healthcare facilities include diligent glove use, consistent hand hygiene, the use of disposable thermometers, and thorough disinfection of the environment to eliminate *C. difficile* spores.
'Evolutionary rescue' describes a situation where a population fails to adapt and faces extinction.
Answer: False
Explanation: Evolutionary rescue refers to the process by which a population adapts to environmental changes, often rapidly, through natural selection, thereby avoiding extinction. The development of antibiotic resistance in bacteria is cited as a potential example of evolutionary rescue.
Antibiotic resistance genes are transmitted only vertically, from parent bacteria to offspring.
Answer: False
Explanation: Antibiotic resistance genes can be transmitted through both vertical gene transmission (parent to offspring) and horizontal gene transmission (between bacteria), including between different species.
What is the primary danger posed by *Clostridioides difficile* in hospitals?
Answer: It is a major cause of death from nosocomial infections.
Explanation: *Clostridioides difficile* is a significant cause of death from nosocomial infections, which are infections acquired during a hospital stay, often leading to severe gastrointestinal issues.
How does antibiotic use increase susceptibility to *C. difficile*?
Answer: Antibiotics kill beneficial gut bacteria, allowing *C. difficile* to proliferate.
Explanation: When the natural balance of symbiotic gut flora is disturbed by antibiotic treatment, an individual becomes more susceptible to opportunistic pathogens like *C. difficile*, as the absence of beneficial bacteria allows *C. difficile* to proliferate.
What characteristic of *C. difficile* spores makes them a significant challenge in hospital sanitation?
Answer: They can remain viable and infectious in the environment for extended periods (up to 20 weeks).
Explanation: *C. difficile* spores can remain viable and infectious in the environment for extended periods, potentially up to 20 weeks. This persistence is particularly problematic in hospitals, where spores can contaminate surfaces and facilitate the spread of infection among patients.
Which human action is cited as worsening antibiotic resistance?
Answer: Not finishing the prescribed course of antibiotics.
Explanation: Antibiotic resistance is worsened by the misuse of antibiotics, such as not completing the prescribed course of treatment. This practice can allow partially resistant bacteria to survive and multiply.
The Red Queen hypothesis in bacterial evolution suggests:
Answer: Bacteria and humans are engaged in a continuous evolutionary arms race.
Explanation: The Red Queen hypothesis, in the context of bacteria and humans, describes an ongoing evolutionary arms race. It suggests that pathogenic bacteria are constantly evolving virulence factors to outcompete human defenses and treatments, while humans (through medicine) evolve countermeasures, creating a continuous cycle of adaptation and counter-adaptation.
What are virulence factors for *C. difficile*?
Answer: Characteristics that enhance pathogenicity, like toxins TcdA and TcdB.
Explanation: Virulence factors are characteristics that enhance pathogenicity. For *C. difficile*, key virulence factors include toxins like enterotoxin TcdA and cytotoxin TcdB, which contribute to its ability to cause severe intestinal issues and resist antibiotic treatments.
What does 'evolutionary rescue' refer to?
Answer: The process where a population adapts to environmental changes to avoid extinction.
Explanation: Evolutionary rescue refers to the process by which a population adapts to environmental changes, often rapidly, through natural selection, thereby avoiding extinction. The development of antibiotic resistance in bacteria is cited as a potential example of evolutionary rescue.
Which of the following is NOT a way human actions exacerbate antibiotic resistance, according to the source?
Answer: Adhering strictly to prescribed dosages and durations.
Explanation: Antibiotic resistance is worsened by the misuse of antibiotics, such as using them for non-bacterial infections, not completing the prescribed course of treatment, or not adhering to the correct dosage. Adhering strictly to prescribed dosages and durations is a practice that helps combat resistance.
What statement accurately describes the transmission of antibiotic resistance genes?
Answer: Through both vertical transmission (parent to offspring) and horizontal transmission (between bacteria).
Explanation: Antibiotic resistance genes can be transmitted through two main pathways: vertical gene transmission, where a resistant bacterium passes the gene to its offspring, and horizontal gene transmission, where one bacterium transfers the resistance gene to another bacterium, even of a different species.
Emergence of antibiotic resistance through pre-existing genetic variations is mentioned as:
Answer: One way antibiotic resistance can emerge in bacteria.
Explanation: Antibiotic resistance can emerge in a bacterial population either through pre-existing genetic variations within the population or through new mutations that arise spontaneously. Both pathways can lead to the development of resistance.
What is the significance of *C. difficile* spores persisting for up to 20 weeks in hospitals?
Answer: It facilitates the spread of infection among patients via contaminated surfaces.
Explanation: *C. difficile* spores can remain viable and infectious in the environment for extended periods, potentially up to 20 weeks. This persistence is particularly problematic in hospitals, where spores can contaminate surfaces and facilitate the spread of infection among patients.
Resistance to pesticides like malathion has been observed in fruit flies infesting orange groves in the US.
Answer: True
Explanation: Studies in the United States have shown that fruit flies infesting orange groves have developed resistance to malathion, a pesticide commonly used to control them. This resistance allows the flies to survive exposure that would typically be lethal.
The diamondback moth developed resistance to *Bacillus thuringiensis* (Bt) approximately 15 years after its widespread use began.
Answer: False
Explanation: The diamondback moth, found in Hawaii and Japan, developed resistance to *Bacillus thuringiensis* (Bt), a bacterium used as a biological pesticide, approximately three years after the widespread use of Bt began.
Rat populations in England have shown resistance to common rat poisons, requiring higher doses for effectiveness.
Answer: True
Explanation: In certain areas of England, rat populations have developed significant resistance to common rat poisons. These resistant rats can consume up to five times the normal lethal dose of the poison without succumbing, posing a challenge for pest control.
DDT remains highly effective in controlling mosquitoes transmitting malaria in all regions where it was historically used.
Answer: False
Explanation: In some regions, DDT (dichlorodiphenyltrichloroethane), a previously effective insecticide, is no longer effective in controlling mosquitoes that transmit malaria. This loss of efficacy has contributed to a resurgence of the disease in those areas.
The weed *Amaranthus palmeri*, problematic in cotton production, has developed resistance to glyphosate herbicide in the southern US.
Answer: True
Explanation: The weed *Amaranthus palmeri*, which poses a problem for cotton production in the southern United States, has developed widespread resistance to glyphosate, a commonly used herbicide. This resistance makes controlling the weed more difficult.
The emergence of pesticide resistance in pests like the diamondback moth is an example of:
Answer: Natural selection acting on populations exposed to chemicals.
Explanation: Similar to antibiotic resistance in bacteria, resistance to pesticides and herbicides has emerged in populations exposed to these agricultural chemicals. This indicates that these chemicals also exert selective pressure on the organisms they target, leading to natural selection.
Which agricultural pest developed resistance to *Bacillus thuringiensis* (Bt) relatively quickly after its introduction?
Answer: Diamondback moths in Hawaii and Japan.
Explanation: The diamondback moth, found in Hawaii and Japan, developed resistance to *Bacillus thuringiensis* (Bt), a bacterium used as a biological pesticide, approximately three years after the widespread use of Bt began.
The observation that rats in England are resistant to common rat poisons demonstrates:
Answer: Selective pressure from the poison has favored resistant rat populations.
Explanation: In certain areas of England, rat populations have developed significant resistance to common rat poisons. These resistant rats can consume up to five times the normal lethal dose of the poison without succumbing, posing a challenge for pest control, which demonstrates selective pressure.
How has the effectiveness of DDT changed in controlling malaria-transmitting mosquitoes?
Answer: It is no longer effective in some regions due to resistance.
Explanation: In some regions, DDT (dichlorodiphenyltrichloroethane), a previously effective insecticide, is no longer effective in controlling mosquitoes that transmit malaria. This loss of efficacy has contributed to a resurgence of the disease in those areas.
Human activities like building roads do not exert evolutionary pressure because they are not biological factors.
Answer: False
Explanation: Human activity can alter environments, creating new pressures that affect populations. Individuals within a population that are better adapted to these human-induced changes are more likely to survive and reproduce, passing on their advantageous traits over generations.
Rattlesnakes inhabiting areas with significant human activity have been observed to exhibit reduced rattling behavior.
Answer: True
Explanation: Rattlesnakes in more heavily populated and trafficked areas are increasingly reported to not rattle. This phenomenon is commonly attributed to selective pressure from humans, who may kill snakes when they are discovered. Non-rattling snakes are less likely to be detected and thus have a higher chance of surviving and reproducing.
Cliff swallow populations situated near roadways in Nebraska have exhibited a decrease in their average wingspan.
Answer: True
Explanation: Cliff swallow populations in Nebraska have shown morphological changes in their wings, specifically a decline in average wingspan, after living near roads for many years. Researchers suspect this is due to selective pressure, as cliff swallows with larger wingspans were more likely to be killed by passing cars.
Human hunting pressure on elk populations tends to favor individuals exhibiting more cautious behavior and reduced activity levels, thereby increasing their chances of evading detection.
Answer: True
Explanation: Human hunting exerts evolutionary pressure on elk by targeting faster and more mobile male elk. This predation pressure favors less active or more cautious individuals, leading to behavioral changes in the elk population over time as survival is linked to avoiding detection by hunters.
Female elk that survive past two years tend to decrease their activity levels each year, increasing their likelihood of survival by reducing their chances of encountering hunters.
Answer: True
Explanation: Studies suggest that female elk who survive past two years tend to decrease their activity levels each year. This behavioral shift towards more timid actions increases their likelihood of survival by reducing their chances of encountering hunters.
The domestication of dogs involved extensive selective breeding by humans, focusing not only on functional traits but also on aesthetic characteristics such as coat color and size.
Answer: True
Explanation: Dog domestication has led to significant evolutionary changes in dogs, driven by selective pressures from humans and the environment. Humans have selectively bred dogs for various traits that suited their needs, resulting in the diverse breeds seen today. Humans have also selected for aesthetic traits, such as specific sizes and coat colors, even when these traits do not offer a clear survival or functional advantage.
An unintended consequence of intensive selective breeding in domesticated dogs is an increased prevalence of heritable diseases within specific breeds.
Answer: True
Explanation: An unintended consequence of selective breeding in domesticated dogs is the increased prevalence of heritable diseases within specific breeds. The intense focus on certain traits can inadvertently concentrate genes associated with various health conditions.
The selective pressure from human hunting on elk primarily favors elk that are more cautious and less active.
Answer: True
Explanation: Human hunting pressure on elk populations tends to favor individuals exhibiting more cautious behavior and reduced activity levels, thereby increasing their chances of evading detection. Female elk who survive past two years tend to decrease their activity levels each year.
Why have rattlesnakes in areas with high human activity been observed to rattle less often?
Answer: Non-rattling snakes are less likely to be detected and killed by humans.
Explanation: Rattlesnakes in more heavily populated and trafficked areas are increasingly reported to not rattle. This phenomenon is commonly attributed to selective pressure from humans, who may kill snakes when they are discovered. Non-rattling snakes are less likely to be detected and thus have a higher chance of surviving and reproducing.
What morphological change has occurred in cliff swallow populations near roads?
Answer: A decrease in average wingspan.
Explanation: Cliff swallow populations in Nebraska have shown morphological changes in their wings, specifically a decline in average wingspan, after living near roads for many years. Researchers suspect this is due to selective pressure, as cliff swallows with larger wingspans were more likely to be killed by passing cars.
How does human hunting exert evolutionary pressure on elk?
Answer: By targeting faster, more mobile male elk, favoring less conspicuous individuals.
Explanation: Human hunting exerts evolutionary pressure on elk by targeting faster and more mobile male elk. This predation pressure favors less active or more cautious individuals, leading to behavioral changes in the elk population over time as survival is linked to avoiding detection by hunters.
Which of the following is an example of human-induced evolutionary pressure mentioned in the source?
Answer: The selective breeding of dogs for specific traits.
Explanation: Examples of human activities that exert evolutionary pressure include building roads, hunting, and the intentional selective breeding of animals like dogs. These actions create environments or select for specific traits that influence the evolutionary trajectory of populations.
The evolution of non-rattling behavior in rattlesnakes near human areas is likely driven by:
Answer: Selection against snakes that alert humans to their presence.
Explanation: Rattlesnakes in more heavily populated and trafficked areas are increasingly reported to not rattle. This phenomenon is commonly attributed to selective pressure from humans, who may kill snakes when they are discovered. Non-rattling snakes are less likely to be detected and thus have a higher chance of surviving and reproducing.
What does the source suggest about older female elk's behavior in relation to hunters?
Answer: They decrease their activity levels to increase survival chances.
Explanation: Studies suggest that female elk who survive past two years tend to decrease their activity levels each year. This behavioral shift towards more timid actions increases their likelihood of survival by reducing their chances of encountering hunters.
What is the primary mechanism driving the diversity of dog breeds?
Answer: Selective breeding by humans for various functional and aesthetic traits.
Explanation: Dog domestication has led to significant evolutionary changes in dogs, driven by selective pressures from humans and the environment. Humans have selectively bred dogs for various traits that suited their needs, resulting in the diverse breeds seen today. Initially, humans selectively bred dogs for practical purposes such as protecting livestock and assisting in hunting.