Unit 4 Test Flashcards
(33 cards)
What are some ways urbanization has changed the environment?
Urbanization has led to the destruction of natural habitats, contributing to biodiversity loss and altering ecosystems. It also increases pollution, such as air, water, and noise, and strains natural resources like water and energy.
How do hawksbeard, juncos, and rats differ in urban vs. non-urban areas?
In urban areas, hawksbeard plants may thrive in disturbed environments like roadsides, while juncos adapt by feeding on human-provided food sources and nesting in buildings. Rats, being opportunistic, are more abundant in cities due to the availability of food and shelter, whereas in non-urban areas, these species may be less reliant on human activity and occupy more natural habitats.
What is natural selection, and how does it play a role in these changes?
Natural selection is the process by which organisms with traits better suited to their environment have a higher chance of survival and reproduction. In urban vs. non-urban areas, species like hawksbeard, juncos, and rats undergo natural selection, where individuals with traits that help them adapt to human-altered environments (such as tolerance to pollution or reliance on human food sources) are more likely to thrive and pass those traits to future generations.
How does habitat fragmentation affect seed dispersal in hawksbeard?
Habitat fragmentation can limit seed dispersal in hawksbeard by isolating populations and reducing the availability of suitable areas for seeds to travel and germinate. With fewer pathways for dispersal, seeds may not reach new areas with the right conditions for growth, leading to a decline in genetic diversity and population size.
Why do hawksbeard plants produce more non-feathery seeds in cities?
Hawksbeard plants produce more non-feathery seeds in cities because these seeds are less reliant on wind for dispersal, making them better suited for the more fragmented, disturbed urban environments. Non-feathery seeds are more likely to drop near the parent plant, which can be advantageous in areas where wind dispersal is less effective due to buildings and limited open spaces.
What role do heritable traits play in adaptation?
Heritable traits play a crucial role in adaptation by allowing beneficial characteristics to be passed down to future generations. These traits increase an organism’s chances of surviving and reproducing in its environment, and over time, populations with these traits become better suited to their surroundings through the process of natural selection.
How did poison act as a selection pressure for rats?
Poison acted as a selection pressure for rats by killing those individuals unable to survive exposure to it, while rats with genetic mutations that offered resistance to the poison survived and reproduced. Over time, these resistant traits became more common in the rat population, leading to a higher proportion of rats that can tolerate poison, making them better adapted to environments where poisoning is used as a control method.
Why did some rats survive while others died?
Some rats survived while others died because of genetic variations that provided resistance to the poison. Rats with mutations that made them less sensitive to the poison or allowed them to metabolize it more effectively were able to survive and reproduce, passing these resistant traits to their offspring. Meanwhile, rats without these protective traits were more likely to die from the poison.
How does sexual reproduction contribute to the spread of resistance?
Sexual reproduction contributes to the spread of resistance by mixing genetic material from two parents, which increases genetic diversity in offspring. This diversity can result in the combination of beneficial resistance traits from both parents, allowing resistant individuals to be more numerous and spread resistance through the population over generations.
Why are city juncos bolder than mountain juncos?
City juncos are bolder than mountain juncos because they are exposed to more human activity and have adapted to living in environments with frequent disturbances. Over time, city juncos may have developed behaviors that allow them to thrive in urban areas, such as being less fearful of humans and more willing to forage in close proximity to them, while mountain juncos, living in more natural settings, retain more cautious behaviors suited to avoiding predators.
What evidence shows that boldness is inherited?
Evidence that boldness is inherited comes from studies showing that offspring of bold individuals tend to exhibit similar bold behaviors. Additionally, when bold and shy individuals are bred, their offspring often display a mix of these traits, indicating that boldness is influenced by genetic factors passed down through generations.
How does stress affect behavior in juncos?
Stress affects behavior in juncos by increasing their levels of anxiety and altering their typical behaviors, such as foraging and mating. In response to stress, juncos may become more cautious or aggressive, and prolonged stress can lead to reduced reproductive success, altered social dynamics, and changes in their overall health and survival.
What are the key ideas of Darwin’s theory of evolution?
Variation: Individuals within a species show variation in traits, such as size, color, or behavior.
Inheritance: Traits are passed down from parents to offspring through genetic inheritance.
Survival of the Fittest: In a given environment, individuals with advantageous traits are more likely to survive and reproduce.
Natural Selection: Over time, these advantageous traits become more common in the population, leading to adaptation to the environment.
Descent with Modification: Species change over time, and new species can arise from common ancestors, showing gradual changes through generations.
How does natural selection explain the changes in hawksbeard, juncos, and rats?
Natural selection explains the changes in hawksbeard, juncos, and rats by highlighting how traits that improve survival and reproduction become more common in a population over time. For hawksbeard, plants with non-feathery seeds are favored in urban environments where wind dispersal is limited. In juncos, bolder individuals that can tolerate human presence are more likely to survive and reproduce in cities, leading to increased boldness in urban populations. For rats, those with genetic resistance to poison survive and reproduce, passing on the resistant traits to future generations, making the population more tolerant of poison over time.
Why is Lamarck’s theory incorrect?
Lamarck’s theory is incorrect because it suggested that organisms can pass on traits acquired during their lifetime to their offspring, such as a giraffe stretching its neck and then having offspring with longer necks. Modern genetics shows that only genetic mutations, not acquired traits, can be passed down to the next generation, meaning changes in an individual’s lifetime do not directly influence the genetic makeup of their descendants.
How does antibiotic resistance in bacteria relate to rat poison resistance?
Antibiotic resistance in bacteria and rat poison resistance are similar because both result from natural selection acting on genetic variations within populations. In both cases, some individuals have genetic mutations that make them resistant to the antibiotic or poison. These individuals survive exposure, reproduce, and pass on the resistance trait to their offspring, increasing the frequency of resistance in the population over time. Just like how rats with poison resistance thrive in environments where poison is used, bacteria with antibiotic resistance become more common in areas where antibiotics are heavily used.
Why does reducing antibiotic use slow resistance?
Reducing antibiotic use slows resistance because it decreases the selective pressure on bacteria to evolve resistance. When antibiotics are overused, bacteria with resistance genes are more likely to survive and reproduce, spreading resistance. By using antibiotics only when necessary, the number of resistant bacteria is reduced, allowing non-resistant strains to survive and preventing the rapid spread of resistance.
What happens to bacterial populations when antibiotics are used frequently?
When antibiotics are used frequently, bacterial populations are exposed to selective pressure, where bacteria with genetic mutations that provide resistance to the antibiotic are more likely to survive and reproduce. As a result, the resistant bacteria become more prevalent in the population, leading to the spread of antibiotic resistance. This makes inf
How does urbanization harm Florida panthers?
Urbanization harms Florida panthers by fragmenting their natural habitat, reducing the amount of land available for hunting, breeding, and migration. As human development encroaches on their territory, panthers face increased risks from vehicle collisions, habitat destruction, and reduced genetic diversity due to isolated populations, further threatening their survival.
Why do some nonhuman populations lose genetic diversity?
Some nonhuman populations lose genetic diversity due to factors like habitat fragmentation, overhunting, or environmental changes that isolate populations. When populations become small or isolated, there is less gene flow between groups, leading to inbreeding and a reduction in genetic variation, which can decrease the population’s ability to adapt to changing environments or resist diseases
What are some ways cities can grow while protecting wildlife?
Cities can grow while protecting wildlife by incorporating green spaces, such as parks and wildlife corridors, that allow animals to move safely through urban areas. Additionally, sustainable building practices, such as using eco-friendly materials and creating green roofs, can help minimize habitat destruction. Planning urban development with consideration for wildlife migration routes and preserving natural habitats can also reduce the negative impacts of urbanization on local ecosystems.
How does fragmentation lead to lower genetic diversity?
Fragmentation leads to lower genetic diversity by isolating populations into smaller, separate groups, reducing the exchange of genetic material between them. With limited movement between fragmented populations, inbreeding becomes more likely, which can increase the frequency of harmful genetic traits and decrease the overall genetic variation, making the population more vulnerable to diseases, environmental changes, and other threats.
Why is genetic diversity important for survival?
Genetic diversity is important for survival because it enhances a population’s ability to adapt to changing environments, resist diseases, and cope with other challenges. Greater genetic variation increases the likelihood that some individuals within a population have traits that allow them to survive in new or shifting conditions, helping the species to persist over time.
How does genetic drift affect small populations?
Genetic drift affects small populations by causing random changes in gene frequencies, which can lead to the loss of genetic variation over time. In small populations, chance events (like the death of individuals or changes in reproductive success) have a greater impact, potentially eliminating rare alleles and reducing genetic diversity, making the population more vulnerable to inbreeding and less adaptable to environmental changes.
