Question 1

In computing an individual's ecological footprint,which of the following would NOT be included?

Accepted Answer

Education level is not directly related to an individual's ecological footprint. The ecological footprint is calculated based on the consumption of resources such as energy, food, goods, and services.

Question 2

Bald eagle populations reached such low numbers in the 1960s that some biologists predicted their extinction in the continental United States; what action appears to have been most significant in reversing their decline?

Accepted Answer

The use of DDT was found to cause thinning of eagle eggshells, leading to fewer young hatching successfully. This was a significant factor contributing to the decline of bald eagles in the United States. In 1972, DDT was banned in the US, leading to a significant recovery of eagle populations.

Question 3

For most populations,irregular fluctuations in size or density

Accepted Answer

Irregular fluctuations in size or density commonly occur before populations reach their carrying capacity. These fluctuations can be caused by factors such as changes in environmental conditions, predation, or disease. The J-shaped growth curve represents exponential growth without any limiting factors, which is less common in natural populations. Density-independent factors can also contribute to irregular fluctuations, but they are not the only cause.

Question 4

Factors such as the age of reproductive maturity,maximum litter size,and the gestation period combine to produce an upper limit for the growth rate of any population; under what circumstances is that rate most likely to be seen?

Accepted Answer

When there are very few individuals in the population, there is less competition for resources, and the population can grow rapidly. As the population grows, however, competition increases, resources become scarce, and the growth rate slows down. Therefore, the growth rate is highest when there are very few individuals in the population, such as the initial colonists in a new habitat or the first few individuals of an introduced species.

Question 5

Which of the following statements about carrying capacity is true?

Accepted Answer

The answer of Which of the following statements about carrying...

Question 6

When an isolated population reaches its carrying capacity

Accepted Answer

The answer of When an isolated population reaches its carrying...

Question 7

Which of the following situations illustrates a link between the effects of density-dependent and density-independent factors?

Accepted Answer

In this scenario, the drought acts as a density-independent factor affecting all deer in the area. However, the survival of the small herd indicates that this population may have been less affected by the density-dependent factors such as competition for food and territory due to its smaller size. Thus, there is a link between the effects of the density-independent factor (drought) and the density-dependent factors (competition and limited resources) in determining the survival of the deer population.

Question 8

Biologists estimate that the human population on Easter Island declined by 90 percent during the 200-year period between AD 1400 and 1600; what accounts for the crash of this population?

Accepted Answer

Deforestation, soil erosion, and resource depletion likely caused the crash of the Easter Island population. The islanders cleared the forests to make farmland and move the moai statues, but this also caused soil erosion and resource depletion. As a result, they could no longer grow enough food to sustain the population, leading to famine, social unrest, and population decline.

Question 9

In 1978,a drought on the Galápagos Islands caused a reduction in the production of seeds that one of the finches,a type of bird,fed upon.This resulted in a decrease from 1,400 to 200 birds.Drought,in this specific situation,

Accepted Answer

Drought is a density-independent factor, meaning that it affects the entire population regardless of its size. In this case, the reduction in seeds affected the survival of the birds and resulted in a decrease in population density from 1,400 to 200 birds. However, it cannot be considered a factor of the carrying capacity, as it is not a limiting resource that would determine the maximum population size that can be sustained.

Question 10

The carrying capacity of owls in an Alaskan forest is 8 per square kilometer.What will happen if 12 owls are confined to a 1-square-kilometer area?

Accepted Answer

The carrying capacity of the Alaskan forest is 8 owls per square kilometer. If 12 owls are confined to a 1-square-kilometer area, the population density will exceed the carrying capacity, resulting in limited resources for the owls. As a result, the owls may survive as malnourished adults, but the next generation will likely have no more than eight individuals. Option A is unlikely as the limited resources may lead to competition and aggression among the owls, rather than sharing resources. Option C is not a direct consequence of the increased owl population, and option D assumes a growth rate that is not feasible in this scenario.

Question 11

The amount of productive land and water that individuals or populations require to provide their required resources and dispose of its wastes is called the

Accepted Answer

The term that best describes the amount of productive land and water required by individuals or populations is the ecological footprint. This term refers to the impact of human activities on the environment as measured by the amount of land needed to support those activities and absorb the waste they generate. The ecological footprint includes the resources consumed to produce food, energy, and other goods, as well as the land and water needed to sequester carbon dioxide emissions and absorb other pollutants.

Question 12

Is it reasonable to expect that all habitats suitable for a given organism will have the same carrying capacity for that organism?

Accepted Answer

The carrying capacity of a habitat is not solely determined by the type of organism, but also by the availability of resources. While essential resources may occur in all suitable habitats, their amounts may vary depending on factors such as climate, topography, and human impact. Therefore, it is not reasonable to expect that all habitats suitable for a given organism will have the same carrying capacity.

Question 13

The Rapanui people initiated the environmental disasters on Easter Island by first

Accepted Answer

The Rapanui people initiated the environmental disasters on Easter Island by removing protective vegetation and exposing the soil to increased erosion. This led to decreased soil fertility, which made it harder to grow crops and sustain their civilization.

Question 14

Examine the following graph,which shows the relationship between planting density and seeds produced per individual plant for Plantago major,also known as plantain weed.  What statement best describes the relationship?

Accepted Answer

As planting density increases, there is a decrease in seed production per plant but total seeds produced remain relatively constant. This can be seen in the plateau of the graph at higher planting densities. At lower planting densities, both seed production per plant and total seeds produced increase. Therefore, option B is the correct statement.

Question 15

Density-dependent factors are more likely to limit population growth when

Accepted Answer

Density-dependent factors, such as competition for resources and diseases, become more significant when there are many individuals living in a limited amount of space. Therefore, A is the best choice. B, C, and D are not likely to have a significant impact on density-dependent factors limiting population growth.

Question 16

The effects of pollution are generally considered to be density independent because

Accepted Answer

Pollution affects organisms at the individual level, regardless of population density. The level of contamination an organism experiences is not impacted by the density of the population around it.

Question 17

The top of the "S" in an S-shaped curve indicates that the population

Accepted Answer

The answer of The top of the "S" in an...

Question 18

The following graph shows the growth of a Paramecium population.  The greatest amount of daily growth occurred when the population was at approximately ________ percent of its carrying capacity.

Accepted Answer

The greatest amount of daily growth occurred when the population was nearing its carrying capacity, which is represented by the flattening out of the curve on the graph. This occurs at around 50 percent of the carrying capacity, where the growth rate is highest before leveling off. Therefore, choice C is the best answer.

Question 19

As a component of its solution for overpopulation,China has imposed a policy that legally limits families to one child; China's government is attempting to manipulate which population factor?

Accepted Answer

The population factor being manipulated by the one-child policy is r, the reproductive rate. By limiting families to only having one child, the government is reducing the number of offspring per couple and therefore reducing the reproductive rate of the population.

Question 20

The following figure shows that the human population was small and relatively stable for nearly 12,000 years but has increased dramatically in the past 200 years.  How might this increase in population growth be explained?

Accepted Answer

The answer of The following figure shows that the human...

Quiz 21: Growth of Populations